Science.gov

Sample records for co2 emission reduction

  1. Reduction of CO2 Emissions Due to Wind Energy - Methods and Issues in Estimating Operational Emission Reductions

    SciTech Connect

    Holttinen, Hannele; Kiviluoma, Juha; McCann, John; Clancy, Matthew; Millgan, Michael; Pineda, Ivan; Eriksen, Peter Borre; Orths, Antje; Wolfgang, Ove

    2015-10-05

    This paper presents ways of estimating CO2 reductions of wind power using different methodologies. Estimates based on historical data have more pitfalls in methodology than estimates based on dispatch simulations. Taking into account exchange of electricity with neighboring regions is challenging for all methods. Results for CO2 emission reductions are shown from several countries. Wind power will reduce emissions for about 0.3-0.4 MtCO2/MWh when replacing mainly gas and up to 0.7 MtCO2/MWh when replacing mainly coal powered generation. The paper focuses on CO2 emissions from power system operation phase, but long term impacts are shortly discussed.

  2. Adaptive Engine Technologies for Aviation CO2 Emissions Reduction

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Haller, William J.; Tong, Michael T.

    2006-01-01

    Adaptive turbine engine technologies are assessed for their potential to reduce carbon dioxide emissions from commercial air transports.Technologies including inlet, fan, and compressor flow control, compressor stall control, blade clearance control, combustion control, active bearings and enabling technologies such as active materials and wireless sensors are discussed. The method of systems assessment is described, including strengths and weaknesses of the approach. Performance benefit estimates are presented for each technology, with a summary of potential emissions reduction possible from the development of new, adaptively controlled engine components.

  3. Estimating the Reduction of Generating System CO2 Emissions Resulting from Significant Wind Energy Penetration

    SciTech Connect

    Holttinen, Hannele; Kiviluoma, Juha; Pineda, Ivan; McCann, John; Clancy, Matthew; Milligan, Michael

    2014-11-13

    This paper presents ways of estimating CO2 reductions of wind power using different methodologies. The paper discusses pitfalls in methodology and proposes appropriate methods to perform the calculations. Results for CO2 emission reductions are shown from several countries. This paper is an international collaboration of IEA Wind Task 25 on wind integration.

  4. Potential CO2 emission reduction by development of non-grain-based bioethanol in China.

    PubMed

    Li, Hongqiang; Wang, Limao; Shen, Lei

    2010-10-01

    Assessment of the potential CO(2) emission reduction by development of non-grain-based ethanol in China is valuable for both setting up countermeasures against climate change and formulating bioethanol policies. Based on the land occupation property, feedstock classification and selection are conducted, identifying sweet sorghum, cassava, and sweet potato as plantation feedstocks cultivated from low-quality arable marginal land resources and molasses and agricultural straws as nonplantation feedstocks derived from agricultural by-products. The feedstock utilization degree, CO(2) reduction coefficient of bioethanol, and assessment model of CO(2) emission reduction potential of bioethanol are proposed and established to assess the potential CO(2) emission reduction by development of non-grain-based bioethanol. The results show that China can obtain emission reduction potentials of 10.947 and 49.027 Mt CO(2) with non-grain-based bioethanol in 2015 and 2030, which are much higher than the present capacity, calculated as 1.95 Mt. It is found that nonplantation feedstock can produce more bioethanol so as to obtain a higher potential than plantation feedstock in both 2015 and 2030. Another finding is that developing non-grain-based bioethanol can make only a limited contribution to China's greenhouse gas emission reduction. Moreover, this study reveals that the regions with low and very low potentials for emission reduction will dominate the spatial distribution in 2015, and regions with high and very high potentials will be the majority in 2030.

  5. Potential CO2 Emission Reduction by Development of Non-Grain-Based Bioethanol in China

    NASA Astrophysics Data System (ADS)

    Li, Hongqiang; Wang, Limao; Shen, Lei

    2010-10-01

    Assessment of the potential CO2 emission reduction by development of non-grain-based ethanol in China is valuable for both setting up countermeasures against climate change and formulating bioethanol policies. Based on the land occupation property, feedstock classification and selection are conducted, identifying sweet sorghum, cassava, and sweet potato as plantation feedstocks cultivated from low-quality arable marginal land resources and molasses and agricultural straws as nonplantation feedstocks derived from agricultural by-products. The feedstock utilization degree, CO2 reduction coefficient of bioethanol, and assessment model of CO2 emission reduction potential of bioethanol are proposed and established to assess the potential CO2 emission reduction by development of non-grain-based bioethanol. The results show that China can obtain emission reduction potentials of 10.947 and 49.027 Mt CO2 with non-grain-based bioethanol in 2015 and 2030, which are much higher than the present capacity, calculated as 1.95 Mt. It is found that nonplantation feedstock can produce more bioethanol so as to obtain a higher potential than plantation feedstock in both 2015 and 2030. Another finding is that developing non-grain-based bioethanol can make only a limited contribution to China’s greenhouse gas emission reduction. Moreover, this study reveals that the regions with low and very low potentials for emission reduction will dominate the spatial distribution in 2015, and regions with high and very high potentials will be the majority in 2030.

  6. Investigation of CO2 emission reduction strategy from in-use gasoline vehicle

    NASA Astrophysics Data System (ADS)

    Choudhary, Arti; Gokhale, Sharad

    2016-04-01

    On road transport emissions is kicking off in Indian cities due to high levels of urbanization and economic growth during the last decade in Indian subcontinent. In 1951, about 17% of India's population were living in urban areas that increased to 32% in 2011. Currently, India is fourth largest Green House Gas (GHG) emitter in the world, with its transport sector being the second largest contributor of CO2 emissions. For achieving prospective carbon reduction targets, substantial opportunity among in-use vehicle is necessary to quantify. Since, urban traffic flow and operating condition has significant impact on exhaust emission (Choudhary and Gokhale, 2016). This study examined the influence of vehicular operating kinetics on CO2 emission from predominant private transportation vehicles of Indian metropolitan city, Guwahati. On-board instantaneous data were used to quantify the impact of CO2 emission on different mileage passenger cars and auto-rickshaws at different times of the day. Further study investigates CO2 emission reduction strategies by using International Vehicle Emission (IVE) model to improve co-benefit in private transportation by integrated effort such as gradual phase-out of inefficient vehicle and low carbon fuel. The analysis suggests that fuel type, vehicles maintenance and traffic flow management have potential for reduction of urban sector GHG emissions. Keywords: private transportation, CO2, instantaneous emission, IVE model Reference Choudhary, A., Gokhale, S. (2016). Urban real-world driving traffic emissions during interruption and congestion. Transportation Research Part D: Transport and Environment 43: 59-70.

  7. Sharing global CO2 emission reductions among one billion high emitters.

    PubMed

    Chakravarty, Shoibal; Chikkatur, Ananth; de Coninck, Heleen; Pacala, Stephen; Socolow, Robert; Tavoni, Massimo

    2009-07-21

    We present a framework for allocating a global carbon reduction target among nations, in which the concept of "common but differentiated responsibilities" refers to the emissions of individuals instead of nations. We use the income distribution of a country to estimate how its fossil fuel CO(2) emissions are distributed among its citizens, from which we build up a global CO(2) distribution. We then propose a simple rule to derive a universal cap on global individual emissions and find corresponding limits on national aggregate emissions from this cap. All of the world's high CO(2)-emitting individuals are treated the same, regardless of where they live. Any future global emission goal (target and time frame) can be converted into national reduction targets, which are determined by "Business as Usual" projections of national carbon emissions and in-country income distributions. For example, reducing projected global emissions in 2030 by 13 GtCO(2) would require the engagement of 1.13 billion high emitters, roughly equally distributed in 4 regions: the U.S., the OECD minus the U.S., China, and the non-OECD minus China. We also modify our methodology to place a floor on emissions of the world's lowest CO(2) emitters and demonstrate that climate mitigation and alleviation of extreme poverty are largely decoupled.

  8. Analyzing and forecasting CO2 emission reduction in China's steel industry

    NASA Astrophysics Data System (ADS)

    Gao, Chengkang; Wang, Dan; Zhao, Baohua; Chen, Shan; Qin, Wei

    2015-03-01

    Recent measures of carbon dioxide emissions from the steel industry of China have indicated a high rate of total CO2 emissions from the industry, even compared to the rest of the world. So, CO2 emission reduction in China's steel industry was analyzed, coupling the whole process and scenarios analysis. First, assuming that all available advanced technologies are almost adopted, this study puts forward some key potential-sectors and explores an optimal technical route for reducing CO2 emissions from the Chinese steel industry based on whole process analysis. The results show that in the stages of coking, sintering, and iron making, greater potential for reducing emissions would be fulfilled by taking some technological measures. If only would above well-developed technologies be fulfill, the CO2 emissions from 5 industry production stages would be reduced substantially, and CO2 emissions per ton of steel could be decreased to 1.24 (ton/ton-steel) by 2020. At the same time, the scenarios analysis indicates that if mature carbon-reducing technologies are adopted, and if the difference between steel output growth rate and the GDP growth rate could be controlled below 3%, CO2 emissions from China's steel industry would approach the goal of reducing CO2 emissions per GDP unit by 40%-45% of the 2005 level by 2020. This indicates that the focus of carbon dioxide emissions reduction in China lies in policy adjustments in order to enhance technological application, and lies in reasonably controlling the pace of growth of GDP and steel output.

  9. Reduction of CO2 and orbital debris: can CO2 emission trading principles be applied to debris reduction?

    NASA Astrophysics Data System (ADS)

    Orlando, Giovanni; Kinnersley, Mark; Starke, Juergen; Hugel, Sebastian; Hartner, Gloria; Singh, Sanjay; Loubiere, Vincent; Staebler, Dominik-Markus; O'Brien-Organ, Christopher; Schwindt, Stefan; Serreau, Francois; Sharma, Mohit

    In the past years global pollution and the specific situation of global warming changes have been strongly influencing public opinion and thus obliged politicians to initiate/ negotiate in-ternational agreements to control, avoid or at least reduce the impact of CO2 emissions e.g. The Kyoto Protocol (1997) and the International Copenhagen conference on Climate Change (2009). In the orbital debris area the collision between the Iridium33 and Cosmos 2251 satel-lites in 2009 has again pushed to the forefront the discussion of the space pollution by space debris and the increasing risk of critical and catastrophic events during the nominal life time of space objects. It is shown by simulations that for Low Earth Orbits the critical debris situation is already achieved and the existing space objects will probably produce sufficient space debris elements -big enough -to support the cascade effect (Kessler Syndrome). In anal-ogy with CO2 emissions, potential recommendations / regulations to reduce the production of Space Debris or its permanence in orbit, are likely to open new markets involving Miti-gation and Removal of Space Debris. The principle approach for the CO2 emission trading model will be investigated and the applicability for the global space debris handling will be analysed. The major differences of the two markets will be derived and the consequences in-dicated. Potential alternative solutions will be proposed and discussed. For the example of the CO2 emission trading principles within EU and worldwide legal conditions for space debris (national / international laws and recommendations) will be considered as well as the commer-cial approach from the controlled situation of dedicated orders to a free / competitive market in steps. It is of interest to consider forms of potential industrial organisations and interna-tional co-operations to react on a similar architecture for the debris removal trading including incentives and penalties for the different

  10. Energetic valorization of wood waste: estimation of the reduction in CO2 emissions.

    PubMed

    Vanneste, J; Van Gerven, T; Vander Putten, E; Van der Bruggen, B; Helsen, L

    2011-09-01

    This paper investigates the potential CO(2) emission reductions related to a partial switch from fossil fuel-based heat and electricity generation to renewable wood waste-based systems in Flanders. The results show that valorization in large-scale CHP (combined heat and power) systems and co-firing in coal plants have the largest CO(2) reduction per TJ wood waste. However, at current co-firing rates of 10%, the CO(2) reduction per GWh of electricity that can be achieved by co-firing in coal plants is five times lower than the CO(2) reduction per GWh of large-scale CHP. Moreover, analysis of the effect of government support for co-firing of wood waste in coal-fired power plants on the marginal costs of electricity generation plants reveals that the effect of the European Emission Trading Scheme (EU ETS) is effectively counterbalanced. This is due to the fact that biomass integrated gasification combined cycles (BIGCC) are not yet commercially available. An increase of the fraction of coal-based electricity in the total electricity generation from 8 to 10% at the expense of the fraction of gas-based electricity due to the government support for co-firing wood waste, would compensate entirely for the CO(2) reduction by substitution of coal by wood waste. This clearly illustrates the possibility of a 'rebound' effect on the CO(2) reduction due to government support for co-combustion of wood waste in an electricity generation system with large installed capacity of coal- and gas-based power plants, such as the Belgian one.

  11. Cement replacement by sugar cane bagasse ash: CO2 emissions reduction and potential for carbon credits.

    PubMed

    Fairbairn, Eduardo M R; Americano, Branca B; Cordeiro, Guilherme C; Paula, Thiago P; Toledo Filho, Romildo D; Silvoso, Marcos M

    2010-09-01

    This paper presents a study of cement replacement by sugar cane bagasse ash (SCBA) in industrial scale aiming to reduce the CO(2) emissions into the atmosphere. SCBA is a by-product of the sugar/ethanol agro-industry abundantly available in some regions of the world and has cementitious properties indicating that it can be used together with cement. Recent comprehensive research developed at the Federal University of Rio de Janeiro/Brazil has demonstrated that SCBA maintains, or even improves, the mechanical and durability properties of cement-based materials such as mortars and concretes. Brazil is the world's largest sugar cane producer and being a developing country can claim carbon credits. A simulation was carried out to estimate the potential of CO(2) emission reductions and the viability to issue certified emission reduction (CER) credits. The simulation was developed within the framework of the methodology established by the United Nations Framework Convention on Climate Change (UNFCCC) for the Clean Development Mechanism (CDM). The State of São Paulo (Brazil) was chosen for this case study because it concentrates about 60% of the national sugar cane and ash production together with an important concentration of cement factories. Since one of the key variables to estimate the CO(2) emissions is the average distance between sugar cane/ethanol factories and the cement plants, a genetic algorithm was developed to solve this optimization problem. The results indicated that SCBA blended cement reduces CO(2) emissions, which qualifies this product for CDM projects. PMID:20493626

  12. Energy conservation and CO2 emission reductions due to recycling in Brazil.

    PubMed

    Pimenteira, C A P; Pereira, A S; Oliveira, L B; Rosa, L P; Reis, M M; Henriques, R M

    2004-01-01

    The present paper aims to make the energy saving potential provided by waste recycling in Brazil evident by pointing out more specifically the benefits regarding climate change mitigation. In this case, based on the energy saved due to the recycling process of an exogenous amount of waste, we have built two scenarios in order to show the potential for indirectly avoiding CO2 emissions in the country as a result of the recycling process. According to the scenario, 1 Mt and 3.5 Mt of CO2, respectively, would be avoided per year due to solid waste recycling. The international context for greenhouse gas emissions reduction, such as the United Nations Framework Convention on Climate Change and its Kyoto Protocol has been taken into account.

  13. Outsourcing CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  14. Willingness to engage in energy conservation and CO2 emissions reduction: An empirical investigation

    NASA Astrophysics Data System (ADS)

    Eluwa, S. E.; Siong, H. C.

    2014-02-01

    Africa's response to climate change has largely been focused on adaptation rather than mitigation. The reason for this is based on the fact that the continent contributes very little to global CO2 emission. Again, mitigation policies like carbon tax as being practised in developed countries may be costly and difficult to implement in a continent where most economies are fragile. Using behavioural change as an adaptation approach, we examined the opinion of Ibadan city residents towards energy conservation and CO2 emissions reduction. A total of 822 respondents were sampled across the three residential neighbourhoods of the city. Results from the study showed that female and male respondents differed in their opinion towards energy conservation. However, the female respondents tended to record higher mean scores on majority of the items used to capture energy conservation behaviour than their male counterparts. Also, those with higher level of education seemed to be more conscious of the environmental consequences arising from energy use at home than those with lower educational background. However, very slight variations were recorded in the mean value score across the different age groups, those respondents above 50 years scored a bit higher than other age groups.

  15. Can the envisaged reductions of fossil fuel CO2 emissions be detected by atmospheric observations?

    PubMed

    Levin, Ingeborg; Rödenbeck, Christian

    2008-03-01

    The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO(2)), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO(2) component (FFCO(2)) by high-precision radiocarbon ((14)C) analyses because FFCO(2) is free of radiocarbon. Long-term observations of (14)CO(2) conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO(2) component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO(2). In this paper, we show that, depending on the remoteness of the site, changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric (14)CO(2) measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO(2) emissions changes in the framework of the Kyoto protocol and successive climate initiatives.

  16. U.S. onroad transportation CO2 emissions analysis comparing highly resolved CO2 emissions and a national average approach : mitigation options and uncertainty reductions

    NASA Astrophysics Data System (ADS)

    Mendoza, D. L.; Gurney, K. R.

    2011-12-01

    The transportation sector is the second largest CO2 emitting economic sector in the United States, accounting for 32.3% of the total U.S. emissions in 2002. Within the transportation sector, the largest component (80%) is made up of onroad emissions. In order to accurately quantify future emissions and evaluate emissions regulation strategies, analysis must account for spatially-explicit fleet distribution, driving patterns, and mitigation strategies. Studies to date, however, have either focused on one of these three components, have been only completed at the national scale, or have not explicitly represented CO2 emissions instead relying on the use of vehicle miles traveled (VMT) as an emissions proxy. We compare a high resolution onroad emissions data product (Vulcan) to a national averaging of the Vulcan result. This comparison is performed in four groupings: light duty (LD) and heavy duty (HD) vehicle classes, and rural and urban road classes. Two different bias metrics are studied: 1) the state-specific, group-specific bias and 2) the same bias when weighted by the state share of the national group-specific emissions. In the first metric, we find a spread of positive and negative biases for the LD and HD vehicle groupings and these biases are driven by states having a greater/lesser proportion of LD/HD vehicles within their total state fleet than found from a national average. The standard deviation of these biases is 2.01% and 0.75% for the LD and HD groupings, respectively. These biases correlate with the road type present in a state, so that biases found in the urban and LD groups are both positive or both negative, with a similar relationship found between biases of the rural and HD groups. Additionally, the road group bias is driven by the distribution of VMT on individual road classes within the road groupings. When normalized by national totals, the state-level group-specific biases reflect states with large amounts of onroad travel that deviate

  17. Reduction of CO2 diffuse emissions from the traditional ceramic industry by the addition of Si-Al raw material.

    PubMed

    González, I; Barba-Brioso, C; Campos, P; Romero, A; Galán, E

    2016-09-15

    The fabrication of ceramics can produce the emission of several gases, denominated exhaust gases, and also vapours resulting from firing processes, which usually contain metals and toxic substances affecting the environment and the health of workers. Especially harmful are the diffuse emissions of CO2, fluorine, chlorine and sulphur from the ceramics industry, which, in highly industrialized areas, can suppose an important emission focus of dangerous effects. Concerning CO2, factories that use carbonate-rich raw materials (>30% carbonates) can emit high concentrations of CO2 to the atmosphere. Thus, carbonate reduction or substitution with other raw materials would reduce the emissions. In this contribution, we propose the addition of Al-shales to the carbonated ceramic materials (marls) for CO2 emission reduction, also improving the quality of the products. The employed shales are inexpensive materials of large reserves in SW-Spain. The ceramic bodies prepared with the addition of selected Al-shale to marls in variable proportions resulted in a 40%-65% CO2 emission reduction. In addition, this research underlines at the same time that the use of a low-price raw material can also contribute to obtaining products with higher added value.

  18. India Co2 Emissions

    NASA Astrophysics Data System (ADS)

    Sharan, S.; Diffenbaugh, N. S.

    2010-12-01

    created a balance in between the “developed” and developing countries. If India was producing the same amounts of emissions per capita as the it would have a total of 20 billion metric tons of CO2 emissions annually.

  19. Reduction of CO(2)-emissions by using biomass in combustion and digestion plants.

    PubMed

    Hoffmann, Gaston; Schingnitz, Daniel; Schnapke, Antje; Bilitewski, Bernd

    2010-05-01

    Climate protection is one of the main aims of environmental policy. One way to advance and push the progress is to reduce the use of fossil fuels for energy production through an increasing production of renewable and CO(2)-neutral energy for example through application of biomass. This paper sets the focus on biomass streams that can be used both thermal and biological for energy production like grass or energy crops. To calculate the potentials of decrease of CO(2)-emissions for treatment of biomass in either combustion or digestion plants some scenarios were set up with different assumptions regarding degree of efficiency of treatment plants which depends on size of plants and the treatment process itself. The energetic utilisation of the considered biomass streams is divided in different utilisation scenarios: combined heat and power generation (CHP) and heat generation or power generation only. Additionally four groups of plant sizes referring to electrical power (from 0.1 up to 10.0MW) were taken into consideration. The calculations of potential savings of CO(2)-emission in both types of treatment scenarios lead to the result that in comparison to biological technologies thermal processes show a much higher utilisation of the energy content in biomass.

  20. Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction

    NASA Astrophysics Data System (ADS)

    Cai, Yongyang; Lenton, Timothy M.; Lontzek, Thomas S.

    2016-05-01

    Evidence suggests that several elements of the climate system could be tipped into a different state by global warming, causing irreversible economic damages. To address their policy implications, we incorporated five interacting climate tipping points into a stochastic-dynamic integrated assessment model, calibrating their likelihoods and interactions on results from an existing expert elicitation. Here we show that combining realistic assumptions about policymakers’ preferences under uncertainty, with the prospect of multiple future interacting climate tipping points, increases the present social cost of carbon in the model nearly eightfold from US$15 per tCO2 to US$116 per tCO2. Furthermore, passing some tipping points increases the likelihood of other tipping points occurring to such an extent that it abruptly increases the social cost of carbon. The corresponding optimal policy involves an immediate, massive effort to control CO2 emissions, which are stopped by mid-century, leading to climate stabilization at <1.5 °C above pre-industrial levels.

  1. EAF Gas Waste Heat Utilization and Discussion of the Energy Conservation and CO2 Emissions Reduction

    NASA Astrophysics Data System (ADS)

    Yang, Ling-zhi; Zhu, Rong; Ma, Guo-hong

    2016-02-01

    As a large number of energy was taken away by the high temperature furnace gas during the EAF smelting process, a huge economic and environmental benefits would obtained to recycle and utilize. In this paper, the energy of the EAF was analyzed theoretically with the hot metal ratio of 50%. Combined with the utilization of the gas waste heat during the scrap preheating, electricity generation, production of steam and production of coal gas processes, the effect of the energy saving and emission was calculated with comprehensive utilization of the high temperature furnace gas. An optimal scheme for utilization of the waste heat was proposed based on the calculation. The results show that the best way for energy saving and carbon reduction is the production of coal gas, while the optimal scheme for waste heat utilization is combined the production of coal gas with the scrap preheating, which will save 170 kWh/t of energy and decrease 57.88 kg/t of carbon emission. As hot metal ratio in EAF steelmaking is often more than 50%, which will produce more EAF gas waste heat, optimizing EAF gas waste heat utilization will have more obvious effect on energy saving and emission reduction.

  2. Implications of the recent reductions in natural gas prices for emissions of CO2 from the US power sector.

    PubMed

    Lu, Xi; Salovaara, Jackson; McElroy, Michael B

    2012-03-01

    CO(2) emissions from the US power sector decreased by 8.76% in 2009 relative to 2008 contributing to a decrease over this period of 6.59% in overall US emissions of greenhouse gases. An econometric model, tuned to data reported for regional generation of US electricity, is used to diagnose factors responsible for the 2009 decrease. More than half of the reduction is attributed to a shift from generation of power using coal to gas driven by a recent decrease in gas prices in response to the increase in production from shale. An important result of the model is that, when the cost differential for generation using gas rather than coal falls below 2-3 cents/kWh, less efficient coal fired plants are displaced by more efficient natural gas combined cycle (NGCC) generation alternatives. Costs for generation using NGCC decreased by close to 4 cents/kWh in 2009 relative to 2008 ensuring that generation of electricity using gas was competitive with coal in 2009 in contrast to the situation in 2008 when gas prices were much higher. A modest price on carbon could contribute to additional switching from coal to gas with further savings in CO(2) emissions.

  3. Implications of the recent reductions in natural gas prices for emissions of CO2 from the US power sector.

    PubMed

    Lu, Xi; Salovaara, Jackson; McElroy, Michael B

    2012-03-01

    CO(2) emissions from the US power sector decreased by 8.76% in 2009 relative to 2008 contributing to a decrease over this period of 6.59% in overall US emissions of greenhouse gases. An econometric model, tuned to data reported for regional generation of US electricity, is used to diagnose factors responsible for the 2009 decrease. More than half of the reduction is attributed to a shift from generation of power using coal to gas driven by a recent decrease in gas prices in response to the increase in production from shale. An important result of the model is that, when the cost differential for generation using gas rather than coal falls below 2-3 cents/kWh, less efficient coal fired plants are displaced by more efficient natural gas combined cycle (NGCC) generation alternatives. Costs for generation using NGCC decreased by close to 4 cents/kWh in 2009 relative to 2008 ensuring that generation of electricity using gas was competitive with coal in 2009 in contrast to the situation in 2008 when gas prices were much higher. A modest price on carbon could contribute to additional switching from coal to gas with further savings in CO(2) emissions. PMID:22321206

  4. Update on CO2 emissions

    SciTech Connect

    Friedingstein, P.; Houghton, R.A.; Marland, Gregg; Hackler, J.; Boden, Thomas A; Conway, T.J.; Canadell, J.G.; Raupach, Mike; Ciais, Philippe; Le Quere, Corrine

    2010-12-01

    Emissions of CO2 are the main contributor to anthropogenic climate change. Here we present updated information on their present and near-future estimates. We calculate that global CO2 emissions from fossil fuel burning decreased by 1.3% in 2009 owing to the global financial and economic crisis that started in 2008; this is half the decrease anticipated a year ago1. If economic growth proceeds as expected2, emissions are projected to increase by more than 3% in 2010, approaching the high emissions growth rates that were observed from 2000 to 20081, 3, 4. We estimate that recent CO2 emissions from deforestation and other land-use changes (LUCs) have declined compared with the 1990s, primarily because of reduced rates of deforestation in the tropics5 and a smaller contribution owing to forest regrowth elsewhere.

  5. Brazilian Energy Policies Side-effects on CO2 Emissions Reduction

    SciTech Connect

    Szklo, Alexandre S.; Schaeffer, Roberto; Schuller, Marcio E.; Chandler, William U.

    2005-02-01

    Uses linear programming techniques and "backcasting" modelling methods to estimate the greenhouse gas emissions mitigation that has resulted in Brazil from policies intended not to address climate change but economic development, energy security, and local environmental protection.

  6. Reduction of Non-CO2 Gas Emissions Through The In Situ Bioconversion of Methane

    SciTech Connect

    Scott, A R; Mukhopadhyay, B; Balin, D F

    2012-09-06

    The primary objectives of this research were to seek previously unidentified anaerobic methanotrophs and other microorganisms to be collected from methane seeps associated with coal outcrops. Subsurface application of these microbes into anaerobic environments has the potential to reduce methane seepage along coal outcrop belts and in coal mines, thereby preventing hazardous explosions. Depending upon the types and characteristics of the methanotrophs identified, it may be possible to apply the microbes to other sources of methane emissions, which include landfills, rice cultivation, and industrial sources where methane can accumulate under buildings. Finally, the microbes collected and identified during this research also had the potential for useful applications in the chemical industry, as well as in a variety of microbial processes. Sample collection focused on the South Fork of Texas Creek located approximately 15 miles east of Durango, Colorado. The creek is located near the subsurface contact between the coal-bearing Fruitland Formation and the underlying Pictured Cliffs Sandstone. The methane seeps occur within the creek and in areas adjacent to the creek where faulting may allow fluids and gases to migrate to the surface. These seeps appear to have been there prior to coalbed methane development as extensive microbial soils have developed. Our investigations screened more than 500 enrichments but were unable to convince us that anaerobic methane oxidation (AMO) was occurring and that anaerobic methanotrophs may not have been present in the samples collected. In all cases, visual and microscopic observations noted that the early stage enrichments contained viable microbial cells. However, as the levels of the readily substrates that were present in the environmental samples were progressively lowered through serial transfers, the numbers of cells in the enrichments sharply dropped and were eliminated. While the results were disappointing we acknowledge that

  7. Increased Use of Natural Gas for Power Generation in the U.S. and the Resulting Reductions in Emissions of CO2, NOx and SO2

    NASA Astrophysics Data System (ADS)

    De Gouw, J. A.; Parrish, D. D.; Trainer, M.

    2013-12-01

    Over the past decades, natural gas has increasingly replaced coal as a fuel for electrical power generation in the U.S. As a result, there have been significant reductions in the emissions of carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur dioxide (SO2). Power plant emissions are continuously measured at the stack using continuous emissions monitoring systems (CEMS) required by the EPA. Previous studies using airborne measurements have shown these CEMS measurements to be accurate. Here, we use annual emissions since 1995 from all point sources included in the CEMS database to quantify the changes in CO2, NOx and SO2 emissions that have resulted from the changing use of fuels and technologies for power generation. In 1997, 83% of electrical power in the CEMS database was generated from coal-fired power plants. In 2012, the contribution from coal had decreased to 59%, and natural gas contributed 34% of the electrical power. Natural gas-fired power plants, in particular those equipped with combined cycle technology, emit less than 50% of CO2 per kWh produced compared to coal-fired plants. As a result of the increased use of natural gas, total CO2 emissions from U.S. power plants have decreased since 2008. In addition, natural gas-fired power plants emit less NOx and far less SO2 per kWh produced than coal-fired power plants. The increased use of natural gas has therefore led to significant emissions reductions of NOx and SO2 in addition to those obtained from the implementation of emissions control systems on coal-fired power plants. The increased use of natural gas for power generation has led to significant reductions in CO2 emissions as well as improvements in U.S. air quality. We will illustrate these points with examples from airborne measurements made using the NOAA WP-3D aircraft in the Southeastern U.S. in 2013 as part of the NOAA Southeast Nexus (SENEX) study. The emissions reductions from U.S. power plants due to the increased use of natural gas will

  8. Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1000 Megawatts (MW) of New Wind Power in Ohio (Fact Sheet)

    SciTech Connect

    Not Available

    2008-06-01

    The U.S. Department of Energy's Wind Powering America Program is committed to educating state-level policy makers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Ohio. We forecast the cumulative economic benefits from 1000 MW of development in Ohio to be $1.3 billion, annual CO2 reductions are estimated at 2.5 million tons, and annual water savings are 1,343 million gallons.

  9. Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1000 Megawatts (MW) of New Wind Power in Nebraska (Fact Sheet)

    SciTech Connect

    Not Available

    2008-06-01

    The U.S. Department of Energy's Wind Powering America Program is committed to educating state-level policy makers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Nebraska. We forecast the cumulative economic benefits from 1000 MW of development in Nebraska to be $1.1 billion, annual CO2 reductions are estimated at 4.1 million tons, and annual water savings are 1,840 million gallons.

  10. Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Nevada (Fact Sheet)

    SciTech Connect

    Not Available

    2008-10-01

    The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Nevada. Although construction and operation of 1000 MW of wind power is a significant effort, six states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in Nevada to be $1.1 billion, annual CO2 reductions are estimated at 2.3 million tons, and annual water savings are 944 million gallons.

  11. Economic Benefits, Carbon Dioxide (CO2) Emissions Reduction, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Georgia (Fact Sheet)

    SciTech Connect

    Not Available

    2008-06-01

    The U.S. Department of Energy's Wind Powering America Program is committed to educating state-level policy makers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Georgia. We forecast the cumulative economic benefits from 1000 MW of development in Georgia to be $2.1 billion, annual CO2 reductions are estimated at 3.0 million tons, and annual water savings are 1,628 million gallons.

  12. Developments in greenhouse gas emissions and net energy use in Danish agriculture - how to achieve substantial CO(2) reductions?

    PubMed

    Dalgaard, T; Olesen, J E; Petersen, S O; Petersen, B M; Jørgensen, U; Kristensen, T; Hutchings, N J; Gyldenkærne, S; Hermansen, J E

    2011-11-01

    Greenhouse gas (GHG) emissions from agriculture are a significant contributor to total Danish emissions. Consequently, much effort is currently given to the exploration of potential strategies to reduce agricultural emissions. This paper presents results from a study estimating agricultural GHG emissions in the form of methane, nitrous oxide and carbon dioxide (including carbon sources and sinks, and the impact of energy consumption/bioenergy production) from Danish agriculture in the years 1990-2010. An analysis of possible measures to reduce the GHG emissions indicated that a 50-70% reduction of agricultural emissions by 2050 relative to 1990 is achievable, including mitigation measures in relation to the handling of manure and fertilisers, optimization of animal feeding, cropping practices, and land use changes with more organic farming, afforestation and energy crops. In addition, the bioenergy production may be increased significantly without reducing the food production, whereby Danish agriculture could achieve a positive energy balance.

  13. PLAINS CO2 REDUCTION PARTNERSHIP

    SciTech Connect

    Edward N. Steadman

    2004-07-01

    The Plains Co{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) activities have focused on developing information on deployment issues to support Task 5 activities by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) activities have focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) has included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 (Modeling and Phase II Action Plans) activities have focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  14. PLAINS CO2 REDUCTION PARTNERSHIP

    SciTech Connect

    Edward N. Steadman; John A. Harju; Erin M. O'Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-01-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  15. PLAINS CO2 REDUCTION PARTNERSHIP

    SciTech Connect

    Edward N. Steadman; John A. Harju; Erin M. O'Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2004-10-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  16. PLAINS CO2 REDUCTION PARTNERSHIP

    SciTech Connect

    Edward N. Steadman; John A. Harju; Erin M. O'Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-04-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) and provided information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 2 efforts also included preparation of a draft topical report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region'', which is nearing completion. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. The video will be completed and aired on Prairie Public Television in the next quarter. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. The addition of the Canadian province of Alberta to the PCOR Partnership region expanded the decision support system (DSS) geographic information system database. Task 5 screened and qualitatively assessed sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  17. PLAINS CO2 REDUCTION PARTNERSHIP

    SciTech Connect

    Edward N. Steadman; John A. Harju; Erin M. O'Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Lisa S. Botnen

    2005-07-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership characterization work is nearing completion, and most remaining efforts are related to finalizing work products. Task 2 (Technology Deployment) has developed a Topical Report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region''. Task 3 (Public Outreach) has developed an informational Public Television program entitled ''Nature in the Balance'', about CO{sub 2} sequestration. The program was completed and aired on Prairie Public Television in this quarter. Task 4 (Sources, Sinks, and Infrastructure) efforts are nearing completion, and data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation are being incorporated into a series of topical reports. The expansion of the Decision Support System Geographic Information System database has continued with the development of a ''save bookmark'' feature that allows users to save a map from the system easily. A feature that allows users to develop a report that summarizes CO{sub 2} sequestration parameters was also developed. Task 5 (Modeling and Phase II Action Plans) focused on screening and qualitatively assessing sequestration options and developing economic estimates for important regional CO{sub 2} sequestration strategies.

  18. CO2 reduction using adsorption followed by nonthermal plasma treatment

    NASA Astrophysics Data System (ADS)

    Nakajima, Kenji; Takahashi, Kazuya; Tanaka, Masanari; Kuroki, Tomoyuki; Okubo, Masaaki

    2015-10-01

    Carbon dioxide (CO2) is one of the main substances linked to global warming, and its emission should be reduced. In this study, a CO2 reduction treatment using an adsorbent and a nonthermal plasma flow is investigated. This treatment comprises a physical adsorption process and nitrogen (N2) plasma reduction process. In the physical adsorption process, CO2 is adsorbed by the adsorbent. In the N2 plasma reduction process, the adsorbed CO2 is reduced to CO by a nonthermal plasma flow that is generated by a plasma reactor with a circulating N2 plasma flow. The generated CO can be reused as a fuel. We estimate this experimental results by calculating conversion efficiency of CO2 to CO. In the N2 plasma reduction process, the CO concentration reaches approximately 1%, regardless of the number of experiments, and conversion efficiency reaches at most 5.3%.

  19. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    SciTech Connect

    Zhou, Nan; Fridley, David; McNeil, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing

    2011-04-01

    China has implemented a series of minimum energy performance standards (MEPS) for over 30 appliances, voluntary energy efficiency label for 40 products and a mandatory energy information label that covers 19 products to date. However, the impact of these programs and their savings potential has not been evaluated on a consistent basis. This paper uses modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, under development or those proposed for development in 2010 under three scenarios that differ in the pace and stringency of MEPS development. In addition to a baseline 'Frozen Efficiency' scenario at 2009 MEPS level, the 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice efficiency in broad commercial use today in 2014. This paper concludes that under 'CIS', cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions of energy used for all 37 products would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction of energy used for 11 appliances would be 35% lower.

  20. Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Massachusetts (Fact Sheet)

    SciTech Connect

    Lantz, E.; Tegen, S.

    2009-03-01

    The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Massachusetts. Although construction and operation of 1000 MW of wind power is a significant effort, seven states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in Massachusetts to be $1.4 billion, annual CO2 reductions are estimated at 2.6 million tons, and annual water savings are 1,293 million gallons.

  1. Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Tennessee (Fact Sheet)

    SciTech Connect

    Lantz, E.; Tegen, S.

    2009-03-01

    The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Tennessee. Although construction and operation of 1000 MW of wind power is a significant effort, seven states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in Tennessee to be $1.2 billion, annual CO2 reductions are estimated at 2.4 million tons, and annual water savings are 1,321 million gallons.

  2. Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in North Carolina (Fact Sheet)

    SciTech Connect

    Not Available

    2009-03-01

    The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in North Carolina. Although construction and operation of 1000 MW of wind power is a significant effort, seven states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in North Carolina to be $1.1 billion, annual CO2 reductions are estimated at 2.9 million tons, and annual water savings are 1,558 million gallons.

  3. Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

    SciTech Connect

    Zhou, Nan; Fridley, David; McNeill, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing; Saheb, Yamina

    2010-06-07

    China is now the world's largest producer and consumer of household appliances and commercial equipment. To address the growth of electricity use of the appliances, China has implemented a series of minimum energy performance standards (MEPS) for 30 appliances, and voluntary energy efficiency label for 40 products. Further, in 2005, China started a mandatory energy information label that covers 19 products to date. However, the impact of these standard and labeling programs and their savings potential has not been evaluated on a consistent basis. This research involved modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, or under development and those proposed for development in 2010. Two scenarios that have been developed differ primarily in the pace and stringency of MEPS development. The 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step considering the technical limitation of the technology. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice MEPS in 2014. This paper concludes that under the 'CIS' of regularly scheduled MEPS revisions to 2030, cumulative electricity consumption could be reduced by 9503 TWh, and annual CO{sub 2} emissions would be 16% lower than in the frozen efficiency scenario. Under a 'BPS' scenario for a subset of products, cumulative electricity savings would be 5450 TWh and annual CO{sub 2} emissions reduction would be 35% lower than in the frozen scenario.

  4. Advanced CO2 Removal and Reduction System

    NASA Technical Reports Server (NTRS)

    Alptekin, Gokhan; Dubovik, Margarita; Copeland, Robert J.

    2011-01-01

    An advanced system for removing CO2 and H2O from cabin air, reducing the CO2, and returning the resulting O2 to the air is less massive than is a prior system that includes two assemblies . one for removal and one for reduction. Also, in this system, unlike in the prior system, there is no need to compress and temporarily store CO2. In this present system, removal and reduction take place within a single assembly, wherein removal is effected by use of an alkali sorbent and reduction is effected using a supply of H2 and Ru catalyst, by means of the Sabatier reaction, which is CO2 + 4H2 CH4 + O2. The assembly contains two fixed-bed reactors operating in alternation: At first, air is blown through the first bed, which absorbs CO2 and H2O. Once the first bed is saturated with CO2 and H2O, the flow of air is diverted through the second bed and the first bed is regenerated by supplying it with H2 for the Sabatier reaction. Initially, the H2 is heated to provide heat for the regeneration reaction, which is endothermic. In the later stages of regeneration, the Sabatier reaction, which is exothermic, supplies the heat for regeneration.

  5. A human development framework for CO2 reductions.

    PubMed

    Costa, Luís; Rybski, Diego; Kropp, Jürgen P

    2011-01-01

    Although developing countries are called to participate in CO(2) emission reduction efforts to avoid dangerous climate change, the implications of proposed reduction schemes in human development standards of developing countries remain a matter of debate. We show the existence of a positive and time-dependent correlation between the Human Development Index (HDI) and per capita CO(2) emissions from fossil fuel combustion. Employing this empirical relation, extrapolating the HDI, and using three population scenarios, the cumulative CO(2) emissions necessary for developing countries to achieve particular HDI thresholds are assessed following a Development As Usual approach (DAU). If current demographic and development trends are maintained, we estimate that by 2050 around 85% of the world's population will live in countries with high HDI (above 0.8). In particular, 300 Gt of cumulative CO(2) emissions between 2000 and 2050 are estimated to be necessary for the development of 104 developing countries in the year 2000. This value represents between 20 % to 30 % of previously calculated CO(2) budgets limiting global warming to 2 °C. These constraints and results are incorporated into a CO(2) reduction framework involving four domains of climate action for individual countries. The framework reserves a fair emission path for developing countries to proceed with their development by indexing country-dependent reduction rates proportional to the HDI in order to preserve the 2 °C target after a particular development threshold is reached. For example, in each time step of five years, countries with an HDI of 0.85 would need to reduce their per capita emissions by approx. 17% and countries with an HDI of 0.9 by 33 %. Under this approach, global cumulative emissions by 2050 are estimated to range from 850 up to 1100 Gt of CO(2). These values are within the uncertainty range of emissions to limit global temperatures to 2 °C. PMID:22216227

  6. Commitment accounting for CO2 emissions

    NASA Astrophysics Data System (ADS)

    Davis, S. J.; Socolow, R. H.

    2013-12-01

    Long-lived energy infrastructure that burns fossil fuels represents a multi-decade 'commitment' to emit CO2. Today's global power sector, alone, represents hundreds of billions of tons of still unrealized 'committed emissions' of CO2. And every year, substantial new commitments to future emissions are made, as new power plants are built. The socioeconomic inertia of these commitments is a major barrier to climate change mitigation. Here, we quantify these annual commitments by a bottom-up analysis of all power plants commissioned between 1950 and 2011; assigning emission commitments to the year when each generator came on line. We find, assuming 40-year commitments, that the global commitment to future emissions from the world's generators in 2011 (the most recent year in our analysis) was 318 Gt CO2, of which 216 Gt CO2 were commitments from the world's coal-fired generators and 134 Gt CO2 were commitments from China's generators. Annual new global commitments exceeded 15 Gt CO2 per year in every year since 2000. Moreover, between 2005-2010 (the latest year of available emissions data), new global commitments were more than twice as large as actual emissions from all power plants. Country-specific ratios of new committed emissions to actual emissions, averaged over 1990-2010 were 4.1 for China, 2.6 for India, 0.9 for the EU, and 0.6 for the US. We urge that the reporting of annual CO2 emissions, already widely institutionalized, be augmented by 'commitment accounting' which makes these future emissions salient. Annual committed emissions and annual emissions of primary power infrastructure. New committed emissions (light green) have grown from approximately 4 Gt CO2 per year in 1960 to roughly 10 Gt CO2 per year between 1970-1995, and then to more than 15 Gt CO2 per year since 2000. Throughout this period, new committed emissions have exceeded annual emissions (blue curve, source: IEA). Although the commitments made 30-40 years ago have largely been realized (dark

  7. Strategic responses to CO2 emission reduction targets drive shift in U.S. electric sector water use

    EPA Science Inventory

    The reliance of the U.S. electric sector on water makes this sector vulnerable to climate change and variability. We use the EPAUS9r MARKAL model to investigate changes in U.S. electric sector water withdrawal and consumption through 2055 under alternative energy system-wide CO2...

  8. Bosch CO2 Reduction System Development

    NASA Technical Reports Server (NTRS)

    Holmes, R. F.; King, C. D.; Keller, E. E.

    1976-01-01

    Development of a Bosch process CO2 reduction unit was continued, and, by means of hardware modifications, the performance was substantially improved. Benefits of the hardware upgrading were demonstrated by extensive unit operation and data acquisition in the laboratory. This work was accomplished on a cold seal configuration of the Bosch unit.

  9. Interactions between reducing CO2 emissions, CO2 removal and solar radiation management.

    PubMed

    Vaughan, Naomi E; Lenton, Timothy M

    2012-09-13

    We use a simple carbon cycle-climate model to investigate the interactions between a selection of idealized scenarios of mitigated carbon dioxide emissions, carbon dioxide removal (CDR) and solar radiation management (SRM). Two CO(2) emissions trajectories differ by a 15-year delay in the start of mitigation activity. SRM is modelled as a reduction in incoming solar radiation that fully compensates the radiative forcing due to changes in atmospheric CO(2) concentration. Two CDR scenarios remove 300 PgC by afforestation (added to vegetation and soil) or 1000 PgC by bioenergy with carbon capture and storage (removed from system). Our results show that delaying the start of mitigation activity could be very costly in terms of the CDR activity needed later to limit atmospheric CO(2) concentration (and corresponding global warming) to a given level. Avoiding a 15-year delay in the start of mitigation activity is more effective at reducing atmospheric CO(2) concentrations than all but the maximum type of CDR interventions. The effects of applying SRM and CDR together are additive, and this shows most clearly for atmospheric CO(2) concentration. SRM causes a significant reduction in atmospheric CO(2) concentration due to increased carbon storage by the terrestrial biosphere, especially soils. However, SRM has to be maintained for many centuries to avoid rapid increases in temperature and corresponding increases in atmospheric CO(2) concentration due to loss of carbon from the land.

  10. The supply chain of CO2 emissions

    PubMed Central

    Davis, Steven J.; Peters, Glen P.; Caldeira, Ken

    2011-01-01

    CO2 emissions from the burning of fossil fuels are conventionally attributed to the country where the emissions are produced (i.e., where the fuels are burned). However, these production-based accounts represent a single point in the value chain of fossil fuels, which may have been extracted elsewhere and may be used to provide goods or services to consumers elsewhere. We present a consistent set of carbon inventories that spans the full supply chain of global CO2 emissions, finding that 10.2 billion tons CO2 or 37% of global emissions are from fossil fuels traded internationally and an additional 6.4 billion tons CO2 or 23% of global emissions are embodied in traded goods. Our results reveal vulnerabilities and benefits related to current patterns of energy use that are relevant to climate and energy policy. In particular, if a consistent and unavoidable price were imposed on CO2 emissions somewhere along the supply chain, then all of the parties along the supply chain would seek to impose that price to generate revenue from taxes collected or permits sold. The geographical concentration of carbon-based fuels and relatively small number of parties involved in extracting and refining those fuels suggest that regulation at the wellhead, mine mouth, or refinery might minimize transaction costs as well as opportunities for leakage. PMID:22006314

  11. An Evaluation Study of the Reduction Effects of the CO2 Emission Quantity and the Primary Energy in the Residential PEFC Co-generation System

    NASA Astrophysics Data System (ADS)

    Maeda, Kazushige; Yonemori, Hideto; Yasaka, Yasuyoshi

    This paper deals with the introduction effects on the basis of the comparative study of residential PEFC (polymer electrolyte fuel cell) co-generation systems and conventional systems that consist of a conventional gas boiler or a condensing gas boiler or a CO2 heat pump and the thermal power plant, by using the computer simulation. The target systems for estimation conform to real systems in the market and the energy demand data acquired from the past field tests was applied. As a result, it becomes clear that the residential PEFC co-generation systems have high performance in the energy saving and the CO2 reduction, from a comparison study with conventional systems and CO2 heat pump system. Concretely to say, the average energy saving rate that the residential PEFC co-generation system provides is 13.9% and the average CO2 reduction rate is 16.5% using quantity of reduction of CO2 as estimate function. Otherwise, the average energy saving rate that the CO2 heat pump system provides is 13.7% and the average CO2 reduction rate is 10.0%. Furthermore, we have proved the effectiveness a radiator in the residential PEFC co-generation system.

  12. Costs of mitigating CO2 emissions from passenger aircraft

    NASA Astrophysics Data System (ADS)

    Schäfer, Andreas W.; Evans, Antony D.; Reynolds, Tom G.; Dray, Lynnette

    2016-04-01

    In response to strong growth in air transportation CO2 emissions, governments and industry began to explore and implement mitigation measures and targets in the early 2000s. However, in the absence of rigorous analyses assessing the costs for mitigating CO2 emissions, these policies could be economically wasteful. Here we identify the cost-effectiveness of CO2 emission reductions from narrow-body aircraft, the workhorse of passenger air transportation. We find that in the US, a combination of fuel burn reduction strategies could reduce the 2012 level of life cycle CO2 emissions per passenger kilometre by around 2% per year to mid-century. These intensity reductions would occur at zero marginal costs for oil prices between US$50-100 per barrel. Even larger reductions are possible, but could impose extra costs and require the adoption of biomass-based synthetic fuels. The extent to which these intensity reductions will translate into absolute emissions reductions will depend on fleet growth.

  13. Uncertainty in gridded CO2 emissions estimates

    NASA Astrophysics Data System (ADS)

    Hogue, Susannah; Marland, Eric; Andres, Robert J.; Marland, Gregg; Woodard, Dawn

    2016-05-01

    We are interested in the spatial distribution of fossil-fuel-related emissions of CO2 for both geochemical and geopolitical reasons, but it is important to understand the uncertainty that exists in spatially explicit emissions estimates. Working from one of the widely used gridded data sets of CO2 emissions, we examine the elements of uncertainty, focusing on gridded data for the United States at the scale of 1° latitude by 1° longitude. Uncertainty is introduced in the magnitude of total United States emissions, the magnitude and location of large point sources, the magnitude and distribution of non-point sources, and from the use of proxy data to characterize emissions. For the United States, we develop estimates of the contribution of each component of uncertainty. At 1° resolution, in most grid cells, the largest contribution to uncertainty comes from how well the distribution of the proxy (in this case population density) represents the distribution of emissions. In other grid cells, the magnitude and location of large point sources make the major contribution to uncertainty. Uncertainty in population density can be important where a large gradient in population density occurs near a grid cell boundary. Uncertainty is strongly scale-dependent with uncertainty increasing as grid size decreases. Uncertainty for our data set with 1° grid cells for the United States is typically on the order of ±150%, but this is perhaps not excessive in a data set where emissions per grid cell vary over 8 orders of magnitude.

  14. PLAINS CO2 REDUCTION (PCOR) PARTNERSHIP

    SciTech Connect

    Edward N. Steadman; Daniel J. Daly; Lynette L. de Silva; John A. Harju; Melanie D. Jensen; Erin M. O'Leary; Wesley D. Peck; Steven A. Smith; James A. Sorensen

    2006-01-01

    During the period of October 1, 2003, through September 30, 2005, the Plains CO2 Reduction (PCOR) Partnership, identified geologic and terrestrial candidates for near-term practical and environmentally sound carbon dioxide (CO2) sequestration demonstrations in the heartland of North America. The PCOR Partnership region covered nine states and three Canadian provinces. The validation test candidates were further vetted to ensure that they represented projects with (1) commercial potential and (2) a mix that would support future projects both dependent and independent of CO2 monetization. This report uses the findings contained in the PCOR Partnership's two dozen topical reports and half-dozen fact sheets as well as the capabilities of its geographic information system-based Decision Support System to provide a concise picture of the sequestration potential for both terrestrial and geologic sequestration in the PCOR Partnership region based on assessments of sources, sinks, regulations, deployment issues, transportation, and capture and separation. The report also includes concise action plans for deployment and public education and outreach as well as a brief overview of the structure, development, and capabilities of the PCOR Partnership. The PCOR Partnership is one of seven regional partnerships under Phase I of the U.S. Department of Energy National Energy Technology Laboratory's Regional Carbon Sequestration Partnership program. The PCOR Partnership, comprising 49 public and private sector members, is led by the Energy & Environmental Research Center at the University of North Dakota. The international PCOR Partnership region includes the Canadian provinces of Alberta, Saskatchewan, and Manitoba and the states of Montana (part), Wyoming (part), North Dakota, South Dakota, Nebraska, Missouri, Iowa, Minnesota, and Wisconsin.

  15. Bosch CO2 Reduction System Development

    NASA Technical Reports Server (NTRS)

    Holmes, R. F.; King, C. D.; Keller, E. E.

    1975-01-01

    Refinements in the design of a Bosch CO2 reduction unit for spacecraft O2 production are described. Sealing of the vacuum insulation jacket was simplified so that high vacuum and high insulation performance are easily maintained. The device includes a relatively simple concentric shell recuperative heat exchanger which operates at approximately 95% temperature effectiveness and helps lower power consumption. The influence of reactor temperature, pressure, and recycle gas composition on power consumption was investigated. In general, precise control is not required since power consumption is not very sensitive to moderate variations of these parameters near their optimum values. There are two process rate control modes which match flow rate to process demand. Catalyst conditioning, support, and packing pattern developments assure consistent starts, reduced energy consumption, and extended cartridge life. Operation levels for four or five men were maintained with overall power input values of 50 to 60 watts per man.

  16. Uncertainty in gridded CO2 emissions estimates

    DOE PAGES

    Hogue, Susannah; Marland, Eric; Andres, Robert J.; Marland, Gregg; Woodard, Dawn

    2016-05-19

    We are interested in the spatial distribution of fossil-fuel-related emissions of CO2 for both geochemical and geopolitical reasons, but it is important to understand the uncertainty that exists in spatially explicit emissions estimates. Working from one of the widely used gridded data sets of CO2 emissions, we examine the elements of uncertainty, focusing on gridded data for the United States at the scale of 1° latitude by 1° longitude. Uncertainty is introduced in the magnitude of total United States emissions, the magnitude and location of large point sources, the magnitude and distribution of non-point sources, and from the use ofmore » proxy data to characterize emissions. For the United States, we develop estimates of the contribution of each component of uncertainty. At 1° resolution, in most grid cells, the largest contribution to uncertainty comes from how well the distribution of the proxy (in this case population density) represents the distribution of emissions. In other grid cells, the magnitude and location of large point sources make the major contribution to uncertainty. Uncertainty in population density can be important where a large gradient in population density occurs near a grid cell boundary. Uncertainty is strongly scale-dependent with uncertainty increasing as grid size decreases. In conclusion, uncertainty for our data set with 1° grid cells for the United States is typically on the order of ±150%, but this is perhaps not excessive in a data set where emissions per grid cell vary over 8 orders of magnitude.« less

  17. Projecting Human Development and CO2 emissions employing correlations

    NASA Astrophysics Data System (ADS)

    Rybski, D.; Costa, L.; Kropp, J. P.

    2012-04-01

    We find positive and time dependent correlation between the Human Development Index (HDI) and per capita CO2 emissions from fossil fuel combustion. Based on this empirical relation, extrapolated HDI, and three population scenarios extracted from the Millennium Ecosystem Assessment report, we estimate future cumulative CO2 emissions. If current demographic and development trends are maintained, we estimate that by 2050 around 85% of the world's population will live in countries with high HDI (above 0.8) as defined in the United Nations Human Development Report 2009. In particular, we estimate that at least 300Gt of cumulative CO2 emissions between 2000 and 2050 are necessary for the development of developing countries in the year 2000. This value represents 30% of a previously calculated CO2 budget yielding a 75% probability of limiting global warming to 2°C. Since human development has been proved to be time and country dependent, we plead for future climate negotiations to consider a differentiated CO2 emissions reduction scheme for developing countries based on the achievement of concrete development goals.

  18. Framework for Assessing Biogenic CO2 Emissions from Stationary Sources

    EPA Science Inventory

    This revision of the 2011 report, Accounting Framework for Biogenic CO2 Emissions from Stationary Sources, evaluates biogenic CO2 emissions from stationary sources, including a detailed study of the scientific and technical issues associated with assessing biogenic carbon dioxide...

  19. Will atmospheric CO2 concentration continue to increase if anthropogenic CO2 emissions cease?

    NASA Astrophysics Data System (ADS)

    MacDougall, A. H.; Eby, M.; Weaver, A. J.

    2013-12-01

    If anthropogenic CO2 emissions were to suddenly cease, the evolution of the atmospheric CO2 concentration would depend on the magnitude and sign of natural carbon sources and sinks. Experiments using Earth system models indicate that overall carbon sinks would dominate. However, these models have typically neglected the permafrost carbon pool, which has the potential to introduce an additional terrestrial source of carbon to the atmosphere. Here we use the University of Victoria Earth System Climate Model, which has recently been expanded to include permafrost carbon stocks and exchanges with the atmosphere. In a scenario of zeroed CO2 and sulphate aerosol emissions, we assess whether the warming induced by specified constant concentrations of non-CO2 greenhouse gases could slow the CO2 decline following zero emissions, or even reverse this trend and cause CO2 to increase over time. We find that a radiative forcing from non-CO2 gases of approximately 0.6 W m-2 results in a near balance of CO2 emissions from the terrestrial biosphere and uptake of CO2 by the oceans, resulting in near-constant atmospheric CO2 concentrations for at least a century after emissions are eliminated. At higher values of non-CO2 radiative forcing, CO2 concentrations increase over time, regardless of when emissions cease during the 21st century. Given that the present-day radiative forcing from non-CO2 greenhouse gases is about 0.95 W m-2, our results suggest that if we were to eliminate all CO2 and aerosols emissions without also decreasing non-CO2 greenhouse gas emissions, CO2 levels would increase over time, resulting in a small increase in climate warming. The sudden and total cessation of anthropogenic CO2 emissions is an unlikely future scenario. However, such cessation experiments provide a useful method for evaluating the relative strength of the terrestrial and oceanic carbon cycle feedbacks in the presence of forcing from non-CO2 greenhouse gasses.

  20. On the proportionality between global temperature change and cumulative CO2 emissions during periods of net negative CO2 emissions

    NASA Astrophysics Data System (ADS)

    Zickfeld, Kirsten; MacDougall, Andrew H.; Damon Matthews, H.

    2016-05-01

    Recent research has demonstrated that global mean surface air warming is approximately proportional to cumulative CO2 emissions. This proportional relationship has received considerable attention, as it allows one to calculate the cumulative CO2 emissions (‘carbon budget’) compatible with temperature targets and is a useful measure for model inter-comparison. Here we use an Earth system model to explore whether this relationship persists during periods of net negative CO2 emissions. Negative CO2 emissions are required in the majority of emissions scenarios limiting global warming to 2 °C above pre-industrial, with emissions becoming net negative in the second half of this century in several scenarios. We find that for model simulations with a symmetric 1% per year increase and decrease in atmospheric CO2, the temperature change (ΔT) versus cumulative CO2 emissions (CE) relationship is nonlinear during periods of net negative emissions, owing to the lagged response of the deep ocean to previously increasing atmospheric CO2. When corrected for this lagged response, or if the CO2 decline is applied after the system has equilibrated with the previous CO2 increase, the ΔT versus CE relationship is close to linear during periods of net negative CO2 emissions. A proportionality constant—the transient climate response to cumulative carbon emissions (TCRE)- can therefore be calculated for both positive and net negative CO2 emission periods. We find that in simulations with a symmetric 1% per year increase and decrease in atmospheric CO2 the TCRE is larger on the upward than on the downward CO2 trajectory, suggesting that positive CO2 emissions are more effective at warming than negative emissions are at subsequently cooling. We also find that the cooling effectiveness of negative CO2 emissions decreases if applied at higher atmospheric CO2 concentrations.

  1. Drivers of the US CO2 emissions 1997–2013

    PubMed Central

    Feng, Kuishuang; Davis, Steven J.; Sun, Laixiang; Hubacek, Klaus

    2015-01-01

    Fossil fuel CO2 emissions in the United States decreased by ∼11% between 2007 and 2013, from 6,023 to 5,377 Mt. This decline has been widely attributed to a shift from the use of coal to natural gas in US electricity production. However, the factors driving the decline have not been quantitatively evaluated; the role of natural gas in the decline therefore remains speculative. Here we analyse the factors affecting US emissions from 1997 to 2013. Before 2007, rising emissions were primarily driven by economic growth. After 2007, decreasing emissions were largely a result of economic recession with changes in fuel mix (for example, substitution of natural gas for coal) playing a comparatively minor role. Energy–climate policies may, therefore, be necessary to lock-in the recent emissions reductions and drive further decarbonization of the energy system as the US economy recovers and grows. PMID:26197104

  2. Drivers of the US CO2 emissions 1997-2013.

    PubMed

    Feng, Kuishuang; Davis, Steven J; Sun, Laixiang; Hubacek, Klaus

    2015-07-21

    Fossil fuel CO2 emissions in the United States decreased by ∼11% between 2007 and 2013, from 6,023 to 5,377 Mt. This decline has been widely attributed to a shift from the use of coal to natural gas in US electricity production. However, the factors driving the decline have not been quantitatively evaluated; the role of natural gas in the decline therefore remains speculative. Here we analyse the factors affecting US emissions from 1997 to 2013. Before 2007, rising emissions were primarily driven by economic growth. After 2007, decreasing emissions were largely a result of economic recession with changes in fuel mix (for example, substitution of natural gas for coal) playing a comparatively minor role. Energy-climate policies may, therefore, be necessary to lock-in the recent emissions reductions and drive further decarbonization of the energy system as the US economy recovers and grows.

  3. Reducing CO2 Emissions through Lightweight Design and Manufacturing

    NASA Astrophysics Data System (ADS)

    Carruth, Mark A.; Allwood, Julian M.; Milford, Rachel L.

    2011-05-01

    To meet targeted 50% reductions in industrial CO2 emissions by 2050, demand for steel and aluminium must be cut. Many steel and aluminium products include redundant material, and the manufacturing routes to produce them use more material than is necessary. Lightweight design and optimized manufacturing processes offer a means of demand reduction, whilst creating products to perform the same service as existing ones. This paper examines two strategies for demand reduction: lightweight product design; and minimizing yield losses through the product supply chain. Possible mass savings are estimated for specific case-studies on metal-intensive products, such as I-beams and food cans. These estimates are then extrapolated to other sectors to produce a global estimate for possible demand reductions. Results show that lightweight product design may offer potential mass savings of up to 30% for some products, whilst yield in the production of others could be improved by over 20%. If these two strategies could be combined for all products, global demand for steel and aluminium would be reduced by nearly 50%. The impact of demand reduction on CO2 emissions is presented, and barriers to the adoption of new, lightweight technologies are discussed.

  4. Continued global warming after CO2 emissions stoppage

    NASA Astrophysics Data System (ADS)

    Froelicher, T. L.; Winton, M.; Sarmiento, J. L.

    2014-12-01

    Recent studies have suggested that global mean surface temperature would remain approximately constant on multi-century timescales after CO2 emissions are stopped. These studies suggest that the cooling effect of reduction in radiative forcing due to the decrease in atmospheric CO2 is roughly balanced by the warming effect of reduction in ocean heat uptake. Here we use Earth system model simulations of such a stoppage to demonstrate that in some models, surface temperature may actually increase on multi-century timescales after an initial century-long decrease. For example, global mean surface temperature may increase by 0.6°C after carbon emissions are stopped at 2°C above preindustrial. Surprisingly, the temperature increase occurs in spite of a decline in radiative forcing that exceeds the decline in ocean heat uptake—a circumstance that would otherwise be expected to lead to a decline in global temperature. The reason is that the warming effect of decreasing ocean heat uptake together with feedback effects arising in response to the geographic structure of ocean heat uptake overcompensates the cooling effect of decreasing atmospheric CO2 on multi-century timescales in these models. We show that ocean heat uptake, which occurs preferentially at subpolar latitudes, has a larger temperature impact per watt per square meter than the CO2 radiative forcing. In other words, the cooling effect of a high-latitude heat sink is larger than that of an equivalent tropical heat sink. The implications of our results for estimates of allowable carbon emissions required to remain below a specific global warming target will be discussed.

  5. Global spatially explicit CO2 emission metrics for forest bioenergy

    NASA Astrophysics Data System (ADS)

    Cherubini, Francesco; Huijbregts, Mark; Kindermann, Georg; van Zelm, Rosalie; van der Velde, Marijn; Stadler, Konstantin; Strømman, Anders Hammer

    2016-02-01

    Emission metrics aggregate climate impacts of greenhouse gases to common units such as CO2-equivalents (CO2-eq.). Examples include the global warming potential (GWP), the global temperature change potential (GTP) and the absolute sustained emission temperature (aSET). Despite the importance of biomass as a primary energy supplier in existing and future scenarios, emission metrics for CO2 from forest bioenergy are only available on a case-specific basis. Here, we produce global spatially explicit emission metrics for CO2 emissions from forest bioenergy and illustrate their applications to global emissions in 2015 and until 2100 under the RCP8.5 scenario. We obtain global average values of 0.49 ± 0.03 kgCO2-eq. kgCO2-1 (mean ± standard deviation) for GWP, 0.05 ± 0.05 kgCO2-eq. kgCO2-1 for GTP, and 2.14·10-14 ± 0.11·10-14 °C (kg yr-1)-1 for aSET. We explore metric dependencies on temperature, precipitation, biomass turnover times and extraction rates of forest residues. We find relatively high emission metrics with low precipitation, long rotation times and low residue extraction rates. Our results provide a basis for assessing CO2 emissions from forest bioenergy under different indicators and across various spatial and temporal scales.

  6. Global spatially explicit CO2 emission metrics for forest bioenergy.

    PubMed

    Cherubini, Francesco; Huijbregts, Mark; Kindermann, Georg; Van Zelm, Rosalie; Van Der Velde, Marijn; Stadler, Konstantin; Strømman, Anders Hammer

    2016-02-02

    Emission metrics aggregate climate impacts of greenhouse gases to common units such as CO2-equivalents (CO2-eq.). Examples include the global warming potential (GWP), the global temperature change potential (GTP) and the absolute sustained emission temperature (aSET). Despite the importance of biomass as a primary energy supplier in existing and future scenarios, emission metrics for CO2 from forest bioenergy are only available on a case-specific basis. Here, we produce global spatially explicit emission metrics for CO2 emissions from forest bioenergy and illustrate their applications to global emissions in 2015 and until 2100 under the RCP8.5 scenario. We obtain global average values of 0.49 ± 0.03 kgCO2-eq. kgCO2(-1) (mean ± standard deviation) for GWP, 0.05 ± 0.05 kgCO2-eq. kgCO2(-1) for GTP, and 2.14·10(-14) ± 0.11·10(-14) °C (kg yr(-1))(-1) for aSET. We explore metric dependencies on temperature, precipitation, biomass turnover times and extraction rates of forest residues. We find relatively high emission metrics with low precipitation, long rotation times and low residue extraction rates. Our results provide a basis for assessing CO2 emissions from forest bioenergy under different indicators and across various spatial and temporal scales.

  7. Atmospheric measurement of point source fossil CO2 emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Baisden, T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2014-05-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m above ground level. We also determined the surface CO2ff content averaged over several weeks from the 14C content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~ one week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14C sampling strategies.

  8. Integration of the electrochemical depolorized CO2 concentrator with the Bosch CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Wynveen, R. A.; Hallick, T. M.

    1976-01-01

    Regenerative processes for the revitalization of spacecraft atmospheres require an Oxygen Reclamation System (ORS) for the collection of carbon dioxide and water vapor and the recovery of oxygen from these metabolic products. Three life support subsystems uniquely qualified to form such an ORS are an Electrochemical CO2 Depolarized Concentrator (EDC), a CO2 Reduction Subsystem (BRS) and a Water Electrolysis Subsystem (WES). A program to develop and test the interface hardware and control concepts necessary for integrated operation of a four man capacity EDC with a four man capacity BRS was successfully completed. The control concept implemented proved successful in operating the EDC with the BRS for both constant CO2 loading as well as variable CO2 loading, based on a repetitive mission profile of the Space Station Prototype (SSP).

  9. CO2 Emissions Measurements at Kilauea Volcano, Hawaii USA

    NASA Astrophysics Data System (ADS)

    Sutton, A. J.; Elias, T.

    2012-12-01

    The importance of volcanic CO2 release in Hawaii has been recognized for at least 100 years. The early gas collections of Jaggar, Shepherd, and Day showed that CO2 was the second most prevalent gas, next to water, in Kilauea's eruptive emissions. As one of Earth's few long-lived, effusive eruptions that have been closely monitored, Kilauea's measured CO2 emissions have served as a global benchmark. At Kilauea in the mid-1980's, conventional airborne, in-plume profiling measurements of CO2 underestimated emissions, due to plume geometry. Remotely-Piloted Aircraft (RPA) and vehicle-based measurements made a decade later showed that at Kilauea, CO2 concentrations were highest near ground level. Methods for quantifying emission rates of CO2 have since been improved via vehicle-based measurements of the ground-hugging plume. Gerlach and others, 2002, used the integrated CO2/SO2 molecular ratio and SO2 emission rate to derive the CO2 emission rate. Their results established a long-term characteristic CO2 emission rate for the summit of Kilauea of 8,500 t/d. This rate was based on several nearly equal measurements spanning a 4 year period, along with an independently reported, steady magma supply rate. Gerlach and others (1998) estimated a contemporaneous east rift CO2 emission rate of 300 t/d. From 2004 to mid-2007, summit CO2 emissions from Kilauea increased twofold on average, and then declined as a surge in magma supply eventually resulted in the forceful opening of a new vent within Halema`uma`u crater at Kilauea's summit in 2008. The elevated summit activity has provided opportunities to test other methods for measuring CO2 abundance in Kilauea's poorly mixed summit plume. Closed space continuous CO2 concentration monitoring within a subsurface vault, recorded transient (minutes-to-days) ambient fluctuations of thousands of parts per million, atop an overall slowly-varying (weeks to months) increase that led up to the 2008 summit eruption. Fumarole gas molecular CO2

  10. Atmospheric Verification of Point Source Fossil Fuel CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Norris, M. W.; Wiltshire, R.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.

    2015-12-01

    Large point sources (electricity generation and large-scale industry) make up roughly one third of all fossil fuel CO2 (CO2ff) emissions. Currently, these emissions are determined from self-reported inventory data, and sometimes from smokestack emissions monitoring, and the uncertainty in emissions from individual power plants is about 20%. We examine the utility of atmospheric 14C measurements combined with atmospheric transport modelling as a tool for independently quantifying point source CO2ff emissions, to both improve the accuracy of the reported emissions and for verification as we move towards a regulatory environment. We use the Kapuni Gas Treatment Facility as a test case. It is located in rural New Zealand with no other significant fossil fuel CO2 sources nearby, and emits CO2ff at ~0.1 Tg carbon per year. We use several different sampling methods to determine the 14C and hence the CO2ff content downwind of the emission source: grab flask samples of whole air; absorption of CO2 into sodium hydroxide integrated over many hours; and plant material which faithfully records the 14C content of assimilated CO2. We use a plume dispersion model to compare the reported emissions with our observed CO2ff mole fractions. We show that the short-term variability in plume dispersion makes it difficult to interpret the grab flask sample results, whereas the variability is averaged out in the integrated samples and we obtain excellent agreement between the reported and observed emissions, indicating that the 14C method can reliably be used to evaluated point source emissions.

  11. Eruptive and diffuse emissions of CO2 from Mount Etna

    NASA Astrophysics Data System (ADS)

    Allard, P.; Carbonnelle, J.; Dajlevic, D.; Le Bronec, J.; Morel, P.

    1991-05-01

    Data collected from 1975 to 1987 are used here to estimate CO2 emissions from the summit craters and upper flanks of Mount Etna. It is found that the average output of CO2 from summit crater degassing is 13 + or - 3 Tg/yr, an order of magnitude higher than the annular CO2 output from Kilauea and representative arc volanoes. Diffuse emissions of CO2 from the upper flanks of Etna are magma-derived and are of a similar magnitude to those emitted from the crater plume. This observation verifies the idea that extensive diffuse release of magmatic CO2 may occur in volcanically active regions. Such degassing may be of use in monitoring volcanic activity, could provide a means for radiocarbon dating of eruptions, and may be a mechanism by which CO2 is injected into crater lakes.

  12. Climate-dependent CO2 emissions from lakes

    NASA Astrophysics Data System (ADS)

    Kosten, Sarian; Roland, FáBio; da Motta Marques, David M. L.; van Nes, Egbert H.; Mazzeo, NéStor; Sternberg, Leonel Da S. L.; Scheffer, Marten; Cole, Jon J.

    2010-06-01

    Inland waters, just as the world's oceans, play an important role in the global carbon cycle. While lakes and reservoirs typically emit CO2, they also bury carbon in their sediment. The net CO2 emission is largely the result of the decomposition or preservation of terrestrially supplied carbon. What regulates the balance between CO2 emission and carbon burial is not known, but climate change and temperature have been hypothesized to influence both processes. We analyzed patterns in carbon dioxide partial pressure (pCO2) in 83 shallow lakes over a large climatic gradient in South America and found a strong, positive correlation with temperature. The higher pCO2 in warmer lakes may be caused by a higher, temperature-dependent mineralization of organic carbon. This pattern suggests that cool lakes may start to emit more CO2 when they warm up because of climate change.

  13. Cost of lower NO x emissions: Increased CO 2 emissions from heavy-duty diesel engines

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Mohan; Carder, Daniel K.; Thompson, Gregory; Gautam, Mridul

    This paper highlights the effect of emissions regulations on in-use emissions from heavy-duty vehicles powered by different model year engines. More importantly, fuel economy data for pre- and post-consent decree engines are compared. The objective of this study was to determine the changes in brake-specific emissions of NO x as a result of emission regulations, and to highlight the effect these have had on brake-specific CO 2 emission; hence, fuel consumption. For this study, in-use, on-road emission measurements were collected. Test vehicles were instrumented with a portable on-board tailpipe emissions measurement system, WVU's Mobile Emissions Measurement System, and were tested on specific routes, which included a mix of highway and city driving patterns, in order to collect engine operating conditions, vehicle speed, and in-use emission rates of CO 2 and NO x. Comparison of on-road in-use emissions data suggests NO x reductions as high as 80% and 45% compared to the US Federal Test Procedure and Not-to-Exceed standards for model year 1995-2002. However, the results indicate that the fuel consumption; hence, CO 2 emissions increased by approximately 10% over the same period, when the engines were operating in the Not-to-Exceed region.

  14. Homogeneous reduction of CO2 by photogenerated pyridinyl radicals.

    PubMed

    Riboni, Francesca; Selli, Elena; Hoffmann, M R; Colussi, A J

    2015-05-14

    We report that 1-hydropyridinyl radicals (1-PyH(•)) photogenerated in solution react with dissolved CO2 en route to its 2e(-) reduction into carboxylic acids. The 254 nm excitation of pyridine (Py) in deaerated 2-PrOH/H2O mixtures saturated with 1 atm of CO2 yields a suite of products, among which we identified Na(HCOO)2(-) (m/z(-) = 113), C5H6NCOO(-) (m/z(-) = 124), and C5H10O2NCOO(-) (m/z(-) = 160) species by electrospray ionization mass spectrometry. These products demonstrably contain carboxylate functionalities that split CO2 neutrals via collisionally induced dissociation. We infer that 1-PyH(•) [from (1) (3)Py* + 2-PrOH → 1-PyH(•) + (•)PrOH] adds to CO2, in competition with radical-radical reactions, leading to intermediates that are in turn reduced by (•)PrOH into the observed species. The formation of carboxylates in this system, which is shown to require CO2, Py, 2-PrOH, and actinic radiation, amounts to the homogeneous 2e(-) reduction of CO2 by 2-PrOH initiated by Py*. We evaluate a rate constant (2) k2(1-PyH(•) + CO2 → (•)Py-1-COOH) ≈ O (10) M(-1) s(-1) and an activation energy E2 ≥ 9 kcal mol(-1) that are compatible with thermochemical estimates for this reaction.

  15. Catalytic Reduction of CO2 by Renewable Organohydrides.

    PubMed

    Lim, Chern-Hooi; Holder, Aaron M; Hynes, James T; Musgrave, Charles B

    2015-12-17

    Dihydropyridines are renewable organohydride reducing agents for the catalytic reduction of CO2 to MeOH. Here we discuss various aspects of this important reduction. A centerpiece, which illustrates various general principles, is our theoretical catalytic mechanism for CO2 reduction by successive hydride transfers (HTs) and proton transfers (PTs) from the dihydropyridine PyH2 obtained by 1H(+)/1e(-)/1H(+)/1e(-) reductions of pyridine. The Py/PyH2 redox couple is analogous to NADP(+)/NADPH in that both are driven to effect HTs by rearomatization. High-energy radical intermediates and their associated high barriers/overpotentials are avoided because HT involves a 2e(-) reduction. A HT-PT sequence dictates that the reduced intermediates be protonated prior to further reduction for ultimate MeOH formation; these protonations are aided by biased cathodes that significantly lower the local pH. In contrast, cathodes that efficiently reduce H(+) such as Pt and Pd produce H2 and create a high interfacial pH, both obstructing dihydropyridine production and formate protonation and thus ultimately CO2 reduction by HTPTs. The role of water molecule proton relays is discussed. Finally, we suggest future CO2 reduction strategies by organic (photo)catalysts. PMID:26722706

  16. Global spatially explicit CO2 emission metrics for forest bioenergy

    PubMed Central

    Cherubini, Francesco; Huijbregts, Mark; Kindermann, Georg; Van Zelm, Rosalie; Van Der Velde, Marijn; Stadler, Konstantin; Strømman, Anders Hammer

    2016-01-01

    Emission metrics aggregate climate impacts of greenhouse gases to common units such as CO2-equivalents (CO2-eq.). Examples include the global warming potential (GWP), the global temperature change potential (GTP) and the absolute sustained emission temperature (aSET). Despite the importance of biomass as a primary energy supplier in existing and future scenarios, emission metrics for CO2 from forest bioenergy are only available on a case-specific basis. Here, we produce global spatially explicit emission metrics for CO2 emissions from forest bioenergy and illustrate their applications to global emissions in 2015 and until 2100 under the RCP8.5 scenario. We obtain global average values of 0.49 ± 0.03 kgCO2-eq. kgCO2−1 (mean ± standard deviation) for GWP, 0.05 ± 0.05 kgCO2-eq. kgCO2−1 for GTP, and 2.14·10−14 ± 0.11·10−14 °C (kg yr−1)−1 for aSET. We explore metric dependencies on temperature, precipitation, biomass turnover times and extraction rates of forest residues. We find relatively high emission metrics with low precipitation, long rotation times and low residue extraction rates. Our results provide a basis for assessing CO2 emissions from forest bioenergy under different indicators and across various spatial and temporal scales. PMID:26830755

  17. Global spatially explicit CO2 emission metrics for forest bioenergy.

    PubMed

    Cherubini, Francesco; Huijbregts, Mark; Kindermann, Georg; Van Zelm, Rosalie; Van Der Velde, Marijn; Stadler, Konstantin; Strømman, Anders Hammer

    2016-01-01

    Emission metrics aggregate climate impacts of greenhouse gases to common units such as CO2-equivalents (CO2-eq.). Examples include the global warming potential (GWP), the global temperature change potential (GTP) and the absolute sustained emission temperature (aSET). Despite the importance of biomass as a primary energy supplier in existing and future scenarios, emission metrics for CO2 from forest bioenergy are only available on a case-specific basis. Here, we produce global spatially explicit emission metrics for CO2 emissions from forest bioenergy and illustrate their applications to global emissions in 2015 and until 2100 under the RCP8.5 scenario. We obtain global average values of 0.49 ± 0.03 kgCO2-eq. kgCO2(-1) (mean ± standard deviation) for GWP, 0.05 ± 0.05 kgCO2-eq. kgCO2(-1) for GTP, and 2.14·10(-14) ± 0.11·10(-14) °C (kg yr(-1))(-1) for aSET. We explore metric dependencies on temperature, precipitation, biomass turnover times and extraction rates of forest residues. We find relatively high emission metrics with low precipitation, long rotation times and low residue extraction rates. Our results provide a basis for assessing CO2 emissions from forest bioenergy under different indicators and across various spatial and temporal scales. PMID:26830755

  18. Analysis of energy-related CO2 emissions and driving factors in five major energy consumption sectors in China.

    PubMed

    Cui, Erqian; Ren, Lijun; Sun, Haoyu

    2016-10-01

    Continual growth of energy-related CO2 emissions in China has received great attention, both domestically and internationally. In this paper, we evaluated the CO2 emissions in five major energy consumption sectors which were evaluated from 1991 to 2012. In order to analyze the driving factors of CO2 emission change in different sectors, the Kaya identity was extended by adding several variables based on specific industrial characteristics and a decomposition analysis model was established according to the LMDI method. The results demonstrated that economic factor was the leading force explaining emission increase in each sector while energy intensity and sector contribution were major contributors to emission mitigation. Meanwhile, CO2 emission intensity had no significant influence on CO2 emission in the short term, and energy consumption structure had a small but growing negative impact on the increase of CO2 emissions. In addition, the future CO2 emissions of industry from 2013 to 2020 under three scenarios were estimated, and the reduction potential of CO2 emissions in industry are 335 Mt in 2020 under lower-emission scenario while the CO2 emission difference between higher-emission scenario and lower-emission scenario is nearly 725 Mt. This paper can offer complementary perspectives on determinants of energy-related CO2 emission change in different sectors and help to formulate mitigation strategies for CO2 emissions.

  19. Analysis of energy-related CO2 emissions and driving factors in five major energy consumption sectors in China.

    PubMed

    Cui, Erqian; Ren, Lijun; Sun, Haoyu

    2016-10-01

    Continual growth of energy-related CO2 emissions in China has received great attention, both domestically and internationally. In this paper, we evaluated the CO2 emissions in five major energy consumption sectors which were evaluated from 1991 to 2012. In order to analyze the driving factors of CO2 emission change in different sectors, the Kaya identity was extended by adding several variables based on specific industrial characteristics and a decomposition analysis model was established according to the LMDI method. The results demonstrated that economic factor was the leading force explaining emission increase in each sector while energy intensity and sector contribution were major contributors to emission mitigation. Meanwhile, CO2 emission intensity had no significant influence on CO2 emission in the short term, and energy consumption structure had a small but growing negative impact on the increase of CO2 emissions. In addition, the future CO2 emissions of industry from 2013 to 2020 under three scenarios were estimated, and the reduction potential of CO2 emissions in industry are 335 Mt in 2020 under lower-emission scenario while the CO2 emission difference between higher-emission scenario and lower-emission scenario is nearly 725 Mt. This paper can offer complementary perspectives on determinants of energy-related CO2 emission change in different sectors and help to formulate mitigation strategies for CO2 emissions. PMID:27397029

  20. Reducing CO2-Emission by using Eco-Cements

    NASA Astrophysics Data System (ADS)

    Voit, K.; Bergmeister, K.; Janotka, I.

    2012-04-01

    CO2 concentration in the air is rising constantly. Globally, cement companies are emitting nearly two billion tonnes/year of CO2 (or around 6 to 7 % of the planet's total CO2 emissions) by producing portland cement clinker. At this pace, by 2025 the cement industry will be emitting CO2 at a rate of 3.5 billion tones/year causing enormous environmental damage (Shi et al., 2011; Janotka et al., 2012). At the dawn of the industrial revolution in the mid-eighteenth century the concentration of CO2 was at a level of ca. 280 ppm. 200 years later at the time of World War II the CO2 level had risen to 310 ppm what results in a rate of increase of 0,15 ppm per year for that period (Shi et al., 2011). In November 2011 the CO2 concentration reached a value of 391 ppm (NOAA Earth System Research Laboratory, 2011), a rise of ca. 81 ppm in 66 years and an increased rate of around 1,2 ppm/year respectively. In the same period cement production in tons of cement has multiplied by a factor of ca. 62 (Kelly & Oss, US Geological Survey, 2010). Thus new CO2-saving eco-cement types are gaining in importance. In these cement types the energy-consuming portland cement clinker is partially replaced by latent hydraulic additives such as blast furnace slag, fly ash or zeolite. These hydraulic additives do not need to be fired in the rotary furnace. They ony need to be pulverized to the required grain size and added to the ground portland cement clinker. Hence energy is saved by skipping the engery-consuming firing process, in addition there is no CO2-degassing as there is in the case of lime burning. Therefore a research project between Austria and Slovakia, funded by the EU (Project ENVIZEO), was initiated in 2010. The main goal of this project is to develop new CEM V eco-types of cements and certificate them for common usage. CEM V is a portland clinker saving cement kind that allows the reduction of clinker to a proportion of 40-64% for CEM V/A and 20-39% for CEM V/B respectively by the

  1. Fleet-wide Emissions from Mobile CO2 Measurements

    NASA Astrophysics Data System (ADS)

    Maness, H.; Thurlow, M. E.; Mcdonald, B. C.; Fung, I. Y.; Harley, R.

    2014-12-01

    In response to regional and municipal policies, transportation agencies are increasingly integrating greenhouse gas considerations into decision making. At the local level, fuel-based methods suffer leakage, mandating a bottom-up approach based on emissions models driven by local activity data. However, high spatial and temporal resolution traffic datasets are in general scarce and subject to error. Emissions models too are based on limited data and often require inputs that are not directly measured. Here, we show that routine, on-road CO2 surface measurements can be used to improve uncertainties on both of these fronts. Using forty hours of surface concentration data collected on CA Highway 24 together with a simple atmospheric dispersion model, we simultaneously derive traffic density as a function of vehicle speed, composite vehicle parameters needed to map vehicle operation to fuel consumption, and baseline meteorological parameters such as wind speed and mixing height. We compare our results directly with traffic loop detector measurements made by California's Performance Measurement System (PeMS), with emissions predictions from EPA's MOtor Vehicle Emission Simulator (MOVES), and with weather station data included in NOAA's Meteorological Assimilation Data Ingest System (MADIS). Using both top-down and bottom-up techniques, we measure the immediate rush-hour emissions reduction associated with congestion alleviation following the opening of the Caldecott Tunnel fourth bore. We use this example to argue that routine and distributed on-road measurements of this kind could serve as a much needed policy tool for testing the impact of traffic-related emissions reduction strategies.

  2. Energy Recovery from End-of-Life Tyres: Untapped Possibility to Reduce CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Dzene, Ilze; Rochas, Claudio; Blumberga, Dagnija; Rosa, Marika; Erdmanis, Andris

    2010-01-01

    In this paper the possibility to reduce CO2 emissions by energy recovery from waste tyres is discussed. The objective of the study is to analyze the end-of-life tyre market in Latvia, to assess the amount of used tyres available and to calculate the potential reduction of CO2 emissions by energy recovery from tyres in mineral products industry. Calculation results show that an improved collection and combustion of end-of-life tyres in the cement industry can save up to 17% of the present CO2 emissions in the mineral products industry.

  3. Independent evaluation of point source fossil fuel CO2 emissions to better than 10.

    PubMed

    Turnbull, Jocelyn Christine; Keller, Elizabeth D; Norris, Margaret W; Wiltshire, Rachael M

    2016-09-13

    Independent estimates of fossil fuel CO2 (CO2ff) emissions are key to ensuring that emission reductions and regulations are effective and provide needed transparency and trust. Point source emissions are a key target because a small number of power plants represent a large portion of total global emissions. Currently, emission rates are known only from self-reported data. Atmospheric observations have the potential to meet the need for independent evaluation, but useful results from this method have been elusive, due to challenges in distinguishing CO2ff emissions from the large and varying CO2 background and in relating atmospheric observations to emission flux rates with high accuracy. Here we use time-integrated observations of the radiocarbon content of CO2 ((14)CO2) to quantify the recently added CO2ff mole fraction at surface sites surrounding a point source. We demonstrate that both fast-growing plant material (grass) and CO2 collected by absorption into sodium hydroxide solution provide excellent time-integrated records of atmospheric (14)CO2 These time-integrated samples allow us to evaluate emissions over a period of days to weeks with only a modest number of measurements. Applying the same time integration in an atmospheric transport model eliminates the need to resolve highly variable short-term turbulence. Together these techniques allow us to independently evaluate point source CO2ff emission rates from atmospheric observations with uncertainties of better than 10%. This uncertainty represents an improvement by a factor of 2 over current bottom-up inventory estimates and previous atmospheric observation estimates and allows reliable independent evaluation of emissions. PMID:27573818

  4. Throwing new light on the reduction of CO2.

    PubMed

    Ozin, Geoffrey A

    2015-03-18

    While the chemical energy in fossil fuels has enabled the rapid rise of modern civilization, their utilization and accompanying anthropogenic CO2 emissions is occurring at a rate that is outpacing nature's carbon cycle. Its effect is now considered to be irreversible and this could lead to the demise of human society. This is a complex issue without a single solution, yet from the burgeoning global research activity and development in the field of CO2 capture and utilization, there is light at the end of the tunnel. In this article a couple of recent advances are illuminated. Attention is focused on the discovery of gas-phase, light-assisted heterogeneous catalytic materials and processes for CO2 photoreduction that operate at sufficiently high rates and conversion efficiencies, and under mild conditions, to open a new pathway for an energy transition from today's "fossil fuel economy" to a new and sustainable "CO2 economy". Whichever of the competing CO2 capture and utilization approaches proves to be the best way forward for the development of a future CO2-based solar fuels economy, hopefully this can occur in a period short enough to circumvent the predicted adverse consequences of greenhouse gas climate change.

  5. Biofuels from crop residue can reduce soil carbon and increase CO2 emissions

    NASA Astrophysics Data System (ADS)

    Liska, Adam J.; Yang, Haishun; Milner, Maribeth; Goddard, Steve; Blanco-Canqui, Humberto; Pelton, Matthew P.; Fang, Xiao X.; Zhu, Haitao; Suyker, Andrew E.

    2014-05-01

    Removal of corn residue for biofuels can decrease soil organic carbon (SOC; refs , ) and increase CO2 emissions because residue C in biofuels is oxidized to CO2 at a faster rate than when added to soil. Net CO2 emissions from residue removal are not adequately characterized in biofuel life cycle assessment (LCA; refs , , ). Here we used a model to estimate CO2 emissions from corn residue removal across the US Corn Belt at 580 million geospatial cells. To test the SOC model, we compared estimated daily CO2 emissions from corn residue and soil with CO2 emissions measured using eddy covariance, with 12% average error over nine years. The model estimated residue removal of 6 Mg per ha-1 yr-1 over five to ten years could decrease regional net SOC by an average of 0.47-0.66 Mg C ha-1 yr-1. These emissions add an average of 50-70 g CO2 per megajoule of biofuel (range 30-90) and are insensitive to the fraction of residue removed. Unless lost C is replaced, life cycle emissions will probably exceed the US legislative mandate of 60% reduction in greenhouse gas (GHG) emissions compared with gasoline.

  6. Systematic Risk Reduction: Chances and Risks of Geological Storage of CO2

    NASA Astrophysics Data System (ADS)

    Schilling, F. R.; Wuerdemann, H.

    2010-12-01

    A profound risk assessment should be the basis of any underground activity such as the geological storage of CO2. The risks and benefits should be weighted, whereas the risks need to be systematically reduced. Even after some decades of geological storage of CO2 (as part of a carbon capture and storage CCS), only a few projects are based on an independent risk assessment. In some cases, a risk assessment was performed after the start of storage operation. Chances: - Are there alternatives to CCS with lower risk? - Is a significant CO2 reduction possible without CCS? - If we accept that CO2 emissions are responsible for climate change having a severe economical impact, we need to substantially reduce CO2 emissions. As long as economic growth is directly related to CO2 emissions, we need to decouple the two. - CCS is one of the few options - may be a necessity, if the energy market is not only dependent on demand. Risks: Beside the risk not to develop and implement CCS, the following risks need to be addressed, ideally in a multi independent risk assessment. - Personal Interests - Acceptance - Political interests - Company interests - HSE (Health Safety Environment) - Risk for Climate and ETS - Operational Risks If a multi independent risk assessment is performed and the risks are addressed in a proper way, a significant and systematic risk reduction can be achieved. Some examples will be given, based on real case studies, such as CO2SINK at Ketzin.

  7. Dynamic of diffuse CO2 emission from Decepcion volcano, Antartica

    NASA Astrophysics Data System (ADS)

    Nolasco, D.; Padron, E.; Hernandez Perez, P. A.; Christian, F.; Kusakabe, M.; Wakita, H.

    2010-12-01

    Deception Island is a volcanic island located at the South Shetland Island off the Antartic Peninsula. It constitutes a back-arc stratovolcano with a basal diameter of ~ 30 Km, the volcano rises ~ 1400 m from the seafloor to the maximum height, Mt. Pond of 540 m above sea level and over half the island is covered by glaciers. This island has a horse-shoe shape with a large flooded caldera with a diameter of about 6x10 km and a maximum depth of 190 m. This caldera is open to the sea through a narrow channel of 500 m at Neptunes Bellows. Deception Island shows the most recent active volcanism, evidence of several eruptions since the late 18th century, and well-known eruptions in 1967, 1969 and 1970 caused serious damage to local scientific stations. The aim of this study is to estimate the CO2 emissions from the Deception volcano bay. In-situ measurements of CO2 efflux from the surface environment of Deception Bay were performed by means of a portable Non Dispersive Infrared spectrophotometer (NDIR) model LICOR Li800, following the accumulation chamber method coupled with a floating device. A total of 244 CO2 efflux measurements were performed in Deception bay in November and December, 2009. CO2 efflux values ranged from non-detectable up to 119,9 g m-2 d-1. To quantify the total CO2 emission from Deception Bay, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (~4 g m-2 d-1), while peak levels (>20 g m-2 d-1) were mainly identified inside the Fumarole Bay, Telefon Bay and Pendulum Cove areas. The total CO2 emission from Deception Bay was estimated about 191 ± 9 t/d To study the temporal evolution of the CO2 efflux values at Fumarole bay, a two month time series of CO2 diffuse emission values was recorded by an automatic geochemical station, which was installed on December 8, 2009, which measured also soil temperature and humidity and meteorological parameters. CO2 values

  8. Global CO2 Emission from Subaerial Volcanism: an additional insight

    NASA Astrophysics Data System (ADS)

    Perez, N.; Hernandez Perez, P. A.; Padron, E.; Melian Rodriguez, G.; Nolasco, D.; Padilla, G.; Barrancos, J.; Rodriguez, F.; Dionis, S.; Hernandez, I.; Calvo, D.; Peraza, M.

    2012-12-01

    During the last two decades, scientists have paid attention to CO2 volcanic emission and its contribution to the global C budget. Excluding MORBs as a net source of CO2 to the atmosphere, the global CO2 discharge from subaerial volcanism has been estimated about ~ 300 Mt yr-1 and this rate accounts for both visible (plume & fumaroles) and non-visible (diffuse) volcanic gas emanations (Mörner & Etíope, 2002). However, CO2 emissions from volcanic lakes had not been considered to estimate the global CO2 discharge from subaerial volcanoes. A recent study by Pérez et al., 2011, has reported that global CO2 emission from volcanic lakes accounts for about 117 ± 19 Mt yr-1, being 94 ± 17 Mt yr-1 as deep-seated CO2. In order to improve the information on the global diffuse CO2 emission estimated by Mörner & Etíope (2002), about 50 Mt yr-1, an extensive research on diffuse CO2 emissions from subaerial volcanoes worldwide has been performed after evaluating the results of 287 diffuse CO2 emission surveys from 83 volcanic systems situated at 24 different countries and volcanic regions. The estimated diffuse CO2 emission at each survey has been normalized by the study area. Statistical-graphical analysis of the data showed three overlapping geochemical populations. The background mean is 2.8 t km-2 d-1 and represents 28.4 % of the total data. Peak population showed a mean of 969.5 t km-2 d-1 and represented 38.0 % of the data, and an intermediate group showed a mean of 72.4 t km-2 d-1 and represents 33.6 % of the data. Taking into account (i) the geometric mean of the normalized CO2 emission rates for each population, (ii) the average of the study area for each population, (iii) the fraction (%) of the three overlapping geochemical populations, and (iv) the number of active subaerial volcanoes in the world (~ 1400); the global diffuse CO2 emission from subaerial volcanism has been estimated about ~ 827 Mt yr-1 of which 437 Mt yr-1 could be reported as deep-seated CO2

  9. Reduction of CO2 to C1 products and fuel

    USGS Publications Warehouse

    Mill, T.; Ross, D.

    2002-01-01

    Photochemical semiconductor processes readily reduced CO2 to a broad range of C1 products. However the intrinsic and solar efficiencies for the processes were low. Improved quantum efficiencies could be realized utilizing quantum-sized particles, but at the expense of using less of the visible solar spectrum. Conversely, semiconductors with small bandgaps used more of the visible solar spectrum at the expense of quantum efficiency. Thermal reduction of CO2 with Fe(II) was thermodynamically favored for forming many kinds of organic compounds and occurred readily with olivine and other Fe(II) minerals above 200??C to form higher alkanes and alkenes. No added hydrogen was required.

  10. Correlations between Human Development and CO2 emissions: projections and implications

    NASA Astrophysics Data System (ADS)

    Rybski, D.; Costa, L.; Kropp, J.

    2011-12-01

    Although developing countries are called to participate on the efforts of reducing CO2 emissions in order to avoid dangerous climate change, the implications of CO2 reduction targets in human development standards of developing countries remain a matter of debate. We find positive and time dependent correlation between the Human Development Index (HDI) and per capita CO2 emissions from fossil fuel combustion. Based on this empirical relation, extrapolated HDI, and three population scenarios extracted from the Millennium Ecosystem Assessment report, we estimate future cumulative CO2 emissions. If current demographic and development trends are maintained, we estimate that by 2050 around 85% of the world's population will live in countries with high HDI (above 0.8) as defined in the United Nations Human Development Report 2009. In particular, we estimate that at least 300Gt of cumulative CO2 emissions between 2000 and 2050 are necessary for the development of developing countries in the year 2000. This value represents 30% of a previously calculated CO2 budget yielding a 75% probability of limiting global warming to 2°C. Since human development has been proved to be time and country dependent, we plead for future climate negotiations to consider a differentiated CO2 emissions reduction scheme for developing countries based on the achievement of concrete development goals.

  11. Emission scenario of non-CO2 gases from energy activities and other sources in China.

    PubMed

    Jiang, Kejun; Hu, Xiulian

    2005-12-01

    This paper gives a quantitative analysis on the non-CO2 emissions related to energy demand, energy activities and land use change of six scenarios with different development pattern in 2030 and 2050 based on IPAC emission model. The various mitigation technologies and policies are assessed to understand the corresponding non-CO2 emission reduction effect. The research shows that the future non-CO2 emissions of China will grow along with increasing energy demand, in which thermal power and transportation will be the major emission and mitigation sectors. During the cause of future social and economic development, the control and mitigation of non-CO2 emissions is a problem as challenging and pressing as that of CO2 emissions. This study indicates that the energy efficiency improvement, renewable energy, advanced nuclear power generation, fuel cell, coal-fired combined cycle, clean coal and motor vehicle emission control technologies will contribute to non-CO2 emissions control and mitigation. PMID:16512217

  12. Emission scenario of non-CO2 gases from energy activities and other sources in China.

    PubMed

    Jiang, Kejun; Hu, Xiulian

    2005-09-01

    This paper gives a quantitative analysis on the non-CO(2) emissions related to energy demand, energy activities and land use change of six scenarios with different development pattern in 2030 and 2050 based on IPAC emission model. The various mitigation technologies and policies are assessed to understand the corresponding non-CO(2) emission reduction effect. The research shows that the future non-CO(2) emissions of China will grow along with increasing energy demand, in which thermal power and transportation will be the major emission and mitigation sectors. During the cause of future social and economic development, the control and mitigation of non-CO(2) emissions is a problem as challenging and pressing as that of CO(2) emissions. This study indicates that the energy efficiency improvement, renewable energy, advanced nuclear power generation, fuel cell, coal-fired combined cycle, clean coal and motor vehicle emission control technologies will contribute to non-CO(2) emissions control and mitigation. PMID:20549450

  13. Emission scenario of non-CO2 gases from energy activities and other sources in China.

    PubMed

    Jiang, Kejun; Hu, Xiulian

    2005-09-01

    This paper gives a quantitative analysis on the non-CO(2) emissions related to energy demand, energy activities and land use change of six scenarios with different development pattern in 2030 and 2050 based on IPAC emission model. The various mitigation technologies and policies are assessed to understand the corresponding non-CO(2) emission reduction effect. The research shows that the future non-CO(2) emissions of China will grow along with increasing energy demand, in which thermal power and transportation will be the major emission and mitigation sectors. During the cause of future social and economic development, the control and mitigation of non-CO(2) emissions is a problem as challenging and pressing as that of CO(2) emissions. This study indicates that the energy efficiency improvement, renewable energy, advanced nuclear power generation, fuel cell, coal-fired combined cycle, clean coal and motor vehicle emission control technologies will contribute to non-CO(2) emissions control and mitigation.

  14. Emission scenario of non-CO2 gases from energy activities and other sources in China.

    PubMed

    Jiang, Kejun; Hu, Xiulian

    2005-12-01

    This paper gives a quantitative analysis on the non-CO2 emissions related to energy demand, energy activities and land use change of six scenarios with different development pattern in 2030 and 2050 based on IPAC emission model. The various mitigation technologies and policies are assessed to understand the corresponding non-CO2 emission reduction effect. The research shows that the future non-CO2 emissions of China will grow along with increasing energy demand, in which thermal power and transportation will be the major emission and mitigation sectors. During the cause of future social and economic development, the control and mitigation of non-CO2 emissions is a problem as challenging and pressing as that of CO2 emissions. This study indicates that the energy efficiency improvement, renewable energy, advanced nuclear power generation, fuel cell, coal-fired combined cycle, clean coal and motor vehicle emission control technologies will contribute to non-CO2 emissions control and mitigation.

  15. Development of an advanced Sabatier CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Cusick, R. J.

    1981-01-01

    A preprototype Sabatier CO2 reduction subsystem was successfully designed, fabricated and tested. The lightweight, quick starting (less than 5 minutes) reactor utlizes a highly active and physically durable methanation catalyst composed of ruthenium on alumina. The use of this improved catalyst permits a simple, passively controlled reactor design with an average lean component H2/CO2 conversion efficiency of over 99% over a range of H2/CO2 molar ratios of 1.8 to 5 while operating with process flows equivalent to a crew size of up to five persons. The subsystem requires no heater operation after start-up even during simulated 55 minute lightside/39 minute darkside orbital operation.

  16. Development of a preprototype sabatier CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Birbara, P.

    1980-01-01

    A preoprototype Sabatier CO2 Reduction Subsystem was successfully designed, fabricated and tested. The lightweight, quick starting reactor utilizes a highly active and physically durable methanation catalyst composed of ruthenium on alumina. The use of this improved catalyst permits a single straight through plug flow design with an average lean component H2/CO2 conversion efficiency of over 99% over a range of H2/CO2 molar ratios of 1.8 to 5 while operating with flows equivalent to a crew size of one person steadystate to 3 persons cyclical (equivalent to 5 persons steady state). The reactor requires no heater operation after start-up even during simulated 55 minute lightside/39 minute darkside orbital operation over the above range of molar ratios and crew loadings. The subsystem's operation and performance is controlled by a microprocessor and displayed on a nineteen inch multi-colored cathode ray tube.

  17. Methane and CO2 emissions from China's hydroelectric reservoirs: a new quantitative synthesis.

    PubMed

    Li, Siyue; Zhang, Quanfa; Bush, Richard T; Sullivan, Leigh A

    2015-04-01

    Controversy surrounds the green credentials of hydroelectricity because of the potentially large emission of greenhouse gases (GHG) from associated reservoirs. However, limited and patchy data particularly for China is constraining the current global assessment of GHG releases from hydroelectric reservoirs. This study provides the first evaluation of the CO2 and CH4 emissions from China's hydroelectric reservoirs by considering the reservoir water surface and drawdown areas, and downstream sources (including spillways and turbines, as well as river downstream). The total emission of 29.6 Tg CO2/year and 0.47 Tg CH4/year from hydroelectric reservoirs in China, expressed as CO2 equivalents (eq), corresponds to 45.6 Tg CO2eq/year, which is 2-fold higher than the current GHG emission (ca. 23 Tg CO2eq/year) from global temperate hydropower reservoirs. China's average emission of 70 g CO2eq/kWh from hydropower amounts to 7% of the emissions from coal-fired plant alternatives. China's hydroelectric reservoirs thus currently mitigate GHG emission when compared to the main alternative source of electricity with potentially far great reductions in GHG emissions and benefits possible through relatively minor changes to reservoir management and design. On average, the sum of drawdown and downstream emission including river reaches below dams and turbines, which is overlooked by most studies, represents the equivalent of 42% of the CO2 and 92% of CH4 that emit from hydroelectric reservoirs in China. Main drivers on GHG emission rates are summarized and highlight that water depth and stratification control CH4 flux, and CO2 flux shows significant negative relationships with pH, DO, and Chl-a. Based on our finding, a substantial revision of the global carbon emissions from hydroelectric reservoirs is warranted.

  18. Methane and CO2 emissions from China's hydroelectric reservoirs: a new quantitative synthesis.

    PubMed

    Li, Siyue; Zhang, Quanfa; Bush, Richard T; Sullivan, Leigh A

    2015-04-01

    Controversy surrounds the green credentials of hydroelectricity because of the potentially large emission of greenhouse gases (GHG) from associated reservoirs. However, limited and patchy data particularly for China is constraining the current global assessment of GHG releases from hydroelectric reservoirs. This study provides the first evaluation of the CO2 and CH4 emissions from China's hydroelectric reservoirs by considering the reservoir water surface and drawdown areas, and downstream sources (including spillways and turbines, as well as river downstream). The total emission of 29.6 Tg CO2/year and 0.47 Tg CH4/year from hydroelectric reservoirs in China, expressed as CO2 equivalents (eq), corresponds to 45.6 Tg CO2eq/year, which is 2-fold higher than the current GHG emission (ca. 23 Tg CO2eq/year) from global temperate hydropower reservoirs. China's average emission of 70 g CO2eq/kWh from hydropower amounts to 7% of the emissions from coal-fired plant alternatives. China's hydroelectric reservoirs thus currently mitigate GHG emission when compared to the main alternative source of electricity with potentially far great reductions in GHG emissions and benefits possible through relatively minor changes to reservoir management and design. On average, the sum of drawdown and downstream emission including river reaches below dams and turbines, which is overlooked by most studies, represents the equivalent of 42% of the CO2 and 92% of CH4 that emit from hydroelectric reservoirs in China. Main drivers on GHG emission rates are summarized and highlight that water depth and stratification control CH4 flux, and CO2 flux shows significant negative relationships with pH, DO, and Chl-a. Based on our finding, a substantial revision of the global carbon emissions from hydroelectric reservoirs is warranted. PMID:25618308

  19. Partitioning of Urban CO2ff Emissions By Source Sector: Results from the Influx Project

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Karion, A.; Sweeney, C.; Newberger, T.; Lehman, S.; Davis, K. J.; Lauvaux, T.; Miles, N. L.; Richardson, S.; Shepson, P. B.; Cambaliza, M. O. L.; Gurney, K. R.; Patarasuk, R.; Whetstone, J. R.

    2014-12-01

    Urban areas contribute ~75% of fossil fuel CO2 (CO2ff) emissions, and city governments are often leading the way in emission reduction efforts. As emissions are regulated and assigned a price, there is an increasing need to independently evaluate the reported bottom-up emissions and to attribute them to specific source sectors (e.g. electricity production, industry, vehicles). We demonstrate how multispecies atmospheric observations can be used to achieve this. The Indianapolis Flux Experiment (INFLUX) aims to develop and evaluate methods for detection and attribution of urban GHG fluxes. The INFLUX observation network includes twelve towers measuring in situ CO2 and CO and flask measurements of another 50 species. 14CO2 measurements have shown that in winter, the total CO2 enhancement over Indianapolis approximates the CO2ff added. This somewhat surprising result allows us to use the wintertime in situ total CO2 and CO measurements to determine the observed CO:CO2ff ratio (RCO) at high resolution. First, we demonstrate that the USEPA CO inventory for Indianapolis overestimates CO emissions by a factor of about 2.5. Then we use the Hestia bottom-up CO2ff data product and revised characteristic RCO values for each CO2ff source sector to predict the diurnal cycle in RCO for Indianapolis. The tower observations and bottom-up RCO estimates are consistent during the daytime, but the observed RCO is significantly higher than the bottom-up estimate during the night. We show how the bottom-up and top-down methods can be used together to determine the cause of this discrepancy and improve CO2ff estimates from both methods.

  20. Devising an integrated methodology for analyzing energy use and CO2 emissions from Taiwan's petrochemical industries.

    PubMed

    Lee, C F; Lin, S J; Lewis, C

    2001-12-01

    Input-output modeling and multiplier analysis are used to assess Taiwan's five petrochemical industries, based upon their economic contribution and potential impacts on energy consumption and CO2 emission. In addition, a consolidated index system was developed for evaluating energy and economic efficiencies as well as targets for CO2 reduction. Results indicate that petrochemical materials (PM) make a major contribution to economic development, with lesser contributions from plastic materials (PL) and artificial fibres (AF). PM has the highest energy multiplier while PL has the largest induced potential for energy consumption. Plastic and rubber products (PP, RP) are relatively insignificant energy consumers. AF has the highest CO2 multiplier, and its induced potential for CO2 emission is the most significant. The consolidated index shows that the upstream petrochemical industries perform rather poorly in an integrated view of economic, energy, and CO2 emission, and should be seen as the primary targets for CO2 reduction. Investment of the petrochemical industries in Taiwan should be adjusted to improve energy efficiency, economic bases, and lower CO2 emissions.

  1. Atmospheric verification of anthropogenic CO2 emission trends

    NASA Astrophysics Data System (ADS)

    Francey, Roger J.; Trudinger, Cathy M.; van der Schoot, Marcel; Law, Rachel M.; Krummel, Paul B.; Langenfelds, Ray L.; Paul Steele, L.; Allison, Colin E.; Stavert, Ann R.; Andres, Robert J.; Rödenbeck, Christian

    2013-05-01

    International efforts to limit global warming and ocean acidification aim to slow the growth of atmospheric CO2, guided primarily by national and industry estimates of production and consumption of fossil fuels. Atmospheric verification of emissions is vital but present global inversion methods are inadequate for this purpose. We demonstrate a clear response in atmospheric CO2 coinciding with a sharp 2010 increase in Asian emissions but show persisting slowing mean CO2 growth from 2002/03. Growth and inter-hemispheric concentration difference during the onset and recovery of the Global Financial Crisis support a previous speculation that the reported 2000-2008 emissions surge is an artefact, most simply explained by a cumulative underestimation (~ 9PgC) of 1994-2007 emissions; in this case, post-2000 emissions would track mid-range of Intergovernmental Panel on Climate Change emission scenarios. An alternative explanation requires changes in the northern terrestrial land sink that offset anthropogenic emission changes. We suggest atmospheric methods to help resolve this ambiguity.

  2. Evaluation of CO2 Emissions from End-use Heat and Power Supplying Systems

    NASA Astrophysics Data System (ADS)

    Kiho, Mariko; Endo, Yasuyuki; Ito, Akito

    It is required for the energy systems to satisfy simultaneous solutions to the problems, such as cost reduction, global warming, assurance of energy security, and resource conservation. To evaluate optimal end-use energy systems from the stand point of CO2 emissions, we apply a comprehensive approach based on the life cycle assessment. Several combinations of electricity and heat supplying systems are compared. They include the electricity driven heat pump, gas engine co-generation, absorption refrigeration and so on. Calculations represent total CO2 emission by energy consumption of several operation patterns, based on the actual data of energy demand, CO2 intensity of the grid electricity and the equipment specifications. The results indicate that CO2 emissions can be minimized by maximum utilization of electricity from the grid.

  3. Development of a stable MnCo2O4 cocatalyst for photocatalytic CO2 reduction with visible light.

    PubMed

    Wang, Sibo; Hou, Yidong; Wang, Xinchen

    2015-02-25

    The synthesis of uniform MnCo2O4 microspheres and their cooperation with a visible light harvester to achieve efficient photocatalytic CO2 reduction under ambient conditions are reported here. The MnCo2O4 materials were prepared by a facile two-step solvothermal-calcination method and were characterized by XRD, SEM, TEM, EDX, XPS, elemental mapping, and N2 adsorption measurements. By using the MnCo2O4 microspheres as a heterogeneous cocatalyst, the photocatalytic performance of the CO2-to-CO conversion catalysis was remarkably enhanced, and no decrease in the promotional effect of the cocatalyst was observed after repeatedly operating the reaction for six cycles. (13)CO2 isotope tracer experiments verified that the CO product originated from the CO2 reactant. The effect of synthetic conditions and various reaction parameters on the photocatalytic activity of the system were investigated and optimized. The stability of the MnCo2O4 cocatalyst in the CO2 reduction system was confirmed by several techniques. Moreover, a possible mechanism for MnCo2O4-cocatalyzed CO2 photoreduction catalysis is proposed. PMID:25646682

  4. Development of a stable MnCo2O4 cocatalyst for photocatalytic CO2 reduction with visible light.

    PubMed

    Wang, Sibo; Hou, Yidong; Wang, Xinchen

    2015-02-25

    The synthesis of uniform MnCo2O4 microspheres and their cooperation with a visible light harvester to achieve efficient photocatalytic CO2 reduction under ambient conditions are reported here. The MnCo2O4 materials were prepared by a facile two-step solvothermal-calcination method and were characterized by XRD, SEM, TEM, EDX, XPS, elemental mapping, and N2 adsorption measurements. By using the MnCo2O4 microspheres as a heterogeneous cocatalyst, the photocatalytic performance of the CO2-to-CO conversion catalysis was remarkably enhanced, and no decrease in the promotional effect of the cocatalyst was observed after repeatedly operating the reaction for six cycles. (13)CO2 isotope tracer experiments verified that the CO product originated from the CO2 reactant. The effect of synthetic conditions and various reaction parameters on the photocatalytic activity of the system were investigated and optimized. The stability of the MnCo2O4 cocatalyst in the CO2 reduction system was confirmed by several techniques. Moreover, a possible mechanism for MnCo2O4-cocatalyzed CO2 photoreduction catalysis is proposed.

  5. Estimates of CO2 traffic emissions from mobile concentration measurements

    NASA Astrophysics Data System (ADS)

    Maness, H. L.; Thurlow, M. E.; McDonald, B. C.; Harley, R. A.

    2015-03-01

    We present data from a new mobile system intended to aid in the design of upcoming urban CO2-monitoring networks. Our collected data include GPS probe data, video-derived traffic density, and accurate CO2 concentration measurements. The method described here is economical, scalable, and self-contained, allowing for potential future deployment in locations without existing traffic infrastructure or vehicle fleet information. Using a test data set collected on California Highway 24 over a 2 week period, we observe that on-road CO2 concentrations are elevated by a factor of 2 in congestion compared to free-flow conditions. This result is found to be consistent with a model including vehicle-induced turbulence and standard engine physics. In contrast to surface concentrations, surface emissions are found to be relatively insensitive to congestion. We next use our model for CO2 concentration together with our data to independently derive vehicle emission rate parameters. Parameters scaling the leading four emission rate terms are found to be within 25% of those expected for a typical passenger car fleet, enabling us to derive instantaneous emission rates directly from our data that compare generally favorably to predictive models presented in the literature. The present results highlight the importance of high spatial and temporal resolution traffic data for interpreting on- and near-road concentration measurements. Future work will focus on transport and the integration of mobile platforms into existing stationary network designs.

  6. Kinetics of CO2 Reduction over Nonstoichiometric Ceria

    PubMed Central

    2015-01-01

    The kinetics of CO2 reduction over nonstoichimetric ceria, CeO2−δ, a material of high potential for thermochemical conversion of sunlight to fuel, has been investigated for a wide range of nonstoichiometries (0.02 ≤ δ ≤ 0.25), temperatures (693 ≤ T ≤ 1273 K), and CO2 concentrations (0.005 ≤ pCO2 ≤ 0.4 atm). Samples were reduced thermally at 1773 K to probe low nonstoichiometries (δ < 0.05) and chemically at lower temperatures in a H2 atmosphere to prevent particle sintering and probe the effect of higher nonstoichiometries (δ < 0.25). For extents greater than δ = 0.2, oxidation rates at a given nonstoichiometry are hindered for the duration of the reaction, presumably because of near-order changes, such as lattice compression, as confirmed via Raman Spectroscopy. Importantly, this behavior is reversible and oxidation rates are not affected at lower δ. Following thermal reduction at very low δ, however, oxidation rates are an order of magnitude slower than those of chemically reduced samples, and rates monotonically increase with the initial nonstoichiometry (up to δ = 0.05). This dependence may be attributed to the formation of stable defect complexes formed between oxygen vacancies and polarons. When the same experiments are performed with 10 mol % Gd3+ doped ceria, in which defect complexes are less prevalent than in pure ceria, this dependence is not observed. PMID:26693270

  7. Mesostructure-Induced Selectivity in CO2 Reduction Catalysis.

    PubMed

    Hall, Anthony Shoji; Yoon, Youngmin; Wuttig, Anna; Surendranath, Yogesh

    2015-12-01

    Gold inverse opal (Au-IO) thin films are active for CO2 reduction to CO with high efficiency at modest overpotentials and high selectivity relative to hydrogen evolution. The specific activity for hydrogen evolution diminishes by 10-fold with increasing porous film thickness, while CO evolution activity is largely unchanged. We demonstrate that the origin of hydrogen suppression in Au-IO films stems from the generation of diffusional gradients within the pores of the mesostructured electrode rather than changes in surface faceting or Au grain size. For electrodes with optimal mesoporosity, 99% selectivity for CO evolution can be obtained at overpotentials as low as 0.4 V. These results establish electrode mesostructuring as a complementary method for tuning selectivity in CO2-to-fuels catalysis. PMID:26536054

  8. Basin scale controls on CO2 and CH4 emissions from the Upper Mississippi River

    NASA Astrophysics Data System (ADS)

    Crawford, John T.; Loken, Luke C.; Stanley, Emily H.; Stets, Edward G.; Dornblaser, Mark M.; Striegl, Robert G.

    2016-03-01

    The Upper Mississippi River, engineered for river navigation in the 1930s, includes a series of low-head dams and navigation pools receiving elevated sediment and nutrient loads from the mostly agricultural basin. Using high-resolution, spatially resolved water quality sensor measurements along 1385 river kilometers, we show that primary productivity and organic matter accumulation affect river carbon dioxide and methane emissions to the atmosphere. Phytoplankton drive CO2 to near or below atmospheric equilibrium during the growing season, while anaerobic carbon oxidation supports a large proportion of the CO2 and CH4 production. Reductions of suspended sediment load, absent of dramatic reductions in nutrients, will likely further reduce net CO2 emissions from the river. Large river pools, like Lake Pepin, which removes the majority of upstream sediments, and large agricultural tributaries downstream that deliver significant quantities of sediments and nutrients, are likely to persist as major geographical drivers of greenhouse gas emissions.

  9. Technology limits for reducing EU transport sector CO2 emissions.

    PubMed

    Dray, Lynnette M; Schäfer, Andreas; Ben-Akiva, Moshe E

    2012-05-01

    Using a new data set describing the techno-economic characteristics of current and projected future transport technologies and a synthesis of existing transport demand models, lifecycle CO(2) emissions from 27 EU countries (EU27) were estimated in the absence and presence of new policy interventions to 2050. Future CO(2) emissions are strongly dependent on geographical scope and economic growth assumptions, and to a lesser extent on uncertainties in technology characteristics, but in the absence of new policy intervention they continue to rise from present-day values in all three scenarios examined. Consequently, EU27 emissions goals, which may require a 60% decrease in transport sector greenhouse gas emissions from year-1990 values by 2050, will be difficult to meet. This is even the case under widespread adoption of the most promising technologies for all modes, due primarily to limitations in biofuel production capacity and a lack of technologies that would drastically reduce CO(2) emissions from heavy trucks and intercontinental aviation.

  10. The impact of CO2 emissions on economic growth: evidence from selected higher CO2 emissions economies.

    PubMed

    Azam, Muhammad; Khan, Abdul Qayyum; Bin Abdullah, Hussin; Qureshi, Muhammad Ejaz

    2016-04-01

    The main purpose of this work is to analyze the impact of environmental degradation proxied by CO2 emissions per capita along with some other explanatory variables namely energy use, trade, and human capital on economic growth in selected higher CO2 emissions economies namely China, the USA, India, and Japan. For empirical analysis, annual data over the period spanning between 1971 and 2013 are used. After using relevant and suitable tests for checking data properties, the panel fully modified ordinary least squares (FMOLS) method is employed as an analytical technique for parameter estimation. The panel group FMOLS results reveal that almost all variables are statistically significant, whereby test rejects the null hypotheses of non cointegration, demonstrating that all variables play an important role in affecting the economic growth role across countries. Where two regressors namely CO2 emissions and energy use show significantly negative impacts on economic growth, for trade and human capital, they tend to show the significantly positive impact on economic growth. However, for the individual analysis across countries, the panel estimate suggests that CO2 emissions have a significant positive relationship with economic growth for China, Japan, and the USA, while it is found significantly negative in case of India. The empirical findings of the study suggest that appropriate and prudent policies are required in order to control pollution emerging from areas other than liquefied fuel consumption. The ultimate impact of shrinking pollution will help in supporting sustainable economic growth and maturation as well as largely improve society welfare.

  11. The impact of CO2 emissions on economic growth: evidence from selected higher CO2 emissions economies.

    PubMed

    Azam, Muhammad; Khan, Abdul Qayyum; Bin Abdullah, Hussin; Qureshi, Muhammad Ejaz

    2016-04-01

    The main purpose of this work is to analyze the impact of environmental degradation proxied by CO2 emissions per capita along with some other explanatory variables namely energy use, trade, and human capital on economic growth in selected higher CO2 emissions economies namely China, the USA, India, and Japan. For empirical analysis, annual data over the period spanning between 1971 and 2013 are used. After using relevant and suitable tests for checking data properties, the panel fully modified ordinary least squares (FMOLS) method is employed as an analytical technique for parameter estimation. The panel group FMOLS results reveal that almost all variables are statistically significant, whereby test rejects the null hypotheses of non cointegration, demonstrating that all variables play an important role in affecting the economic growth role across countries. Where two regressors namely CO2 emissions and energy use show significantly negative impacts on economic growth, for trade and human capital, they tend to show the significantly positive impact on economic growth. However, for the individual analysis across countries, the panel estimate suggests that CO2 emissions have a significant positive relationship with economic growth for China, Japan, and the USA, while it is found significantly negative in case of India. The empirical findings of the study suggest that appropriate and prudent policies are required in order to control pollution emerging from areas other than liquefied fuel consumption. The ultimate impact of shrinking pollution will help in supporting sustainable economic growth and maturation as well as largely improve society welfare. PMID:26620862

  12. 40 CFR 75.13 - Specific provisions for monitoring CO2 emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... monitoring CO2 emissions. (a) CO 2 continuous emission monitoring system. If the owner or operator chooses to... operating requirements in § 75.10 for a CO2 continuous emission monitoring system and flow monitoring system... §§ 75.11(a) through (e) or § 75.16, except that the phrase “CO2 continuous emission monitoring...

  13. Viability and metal reduction of Shewanella oneidensis MR-1 under CO2 stress: implications for ecological effects of CO2 leakage from geologic CO2 sequestration.

    PubMed

    Wu, Bing; Shao, Hongbo; Wang, Zhipeng; Hu, Yandi; Tang, Yinjie J; Jun, Young-Shin

    2010-12-01

    To study potential ecological impacts of CO(2) leakage to shallow groundwater and soil/sediments from geologic CO(2) sequestration (GCS) sites, this work investigated the viability and metal reduction of Shewanella oneidensis MR-1 under CO(2) stress. While MR-1 could grow under high-pressure nitrogen gas (500 psi), the mix of 1% CO(2) with N(2) at total pressures of 15 or 150 psi significantly suppressed the growth of MR-1, compared to the N(2) control. When CO(2) partial pressures were over 15 psi, the growth of MR-1 stopped. The reduced bacterial viability was consistent with the pH decrease and cellular membrane damage under high pressure CO(2). After exposure to 150 psi CO(2) for 5 h, no viable cells survived, the cellular contents were released, and microscopy images confirmed significant cell structure deformation. However, after a relatively short exposure (25 min) to 150 psi CO(2), MR-1 could fully recover their growth within 24 h after the stress was removed, and the reduction of MnO(2) by MR-1 was observed right after the stress was removed. Furthermore, MR-1 survived better if the cells were aggregated rather than suspended, or if pH buffering minerals, such as calcite, were present. To predict the cell viability under different CO(2) pressures and exposure times, a two-parameter mathematical model was developed.

  14. Reconstruction of historic fossil CO2 emissions using radiocarbonmeasurements from tree rings

    NASA Astrophysics Data System (ADS)

    Norris, M. W.; Turnbull, J. C.; Trimble, M.; Keller, E. D.; Baisden, W. T.; Renwick, J. A.

    2014-12-01

    This project aims to reconstruct historic fossil CO2 emissions from a point source. As a test case we use the Vector gas processing plant in Taranaki New Zealand which has emitted 0.1Tg C yr-1 (as CO2) since 1970. Previous work using air samples found 2-5 ppm mole fraction CO2ff 600m downwind of the plant; this study extends the data set back 30 years using radiocarbon measurements in tree rings. Trees incorporate CO2 from the local atmosphere into their cellulose which is laid down in annual growth rings during photosynthesis. To relate this to the fossil CO2 content of the air we measure 14C in annual tree rings at a local clean air site and compare this to measurements of 14C in the annual ring for the same year at our test site. Fossil CO2 is devoid of 14C so addition of CO2ff will cause an observed decrease in14C in samples directly related to the amount of CO2ff present. Trees growing immediately downwind of the Vector plant and from clean air locations in Taranaki and Wellington were cored. Annual rings were counted and cut into one year growth increments. Testing was performed on two cellulose extraction methods to confirm removal of contaminating material before the cellulose component was chemically isolated, combusted, graphitised and 14C measured by Accelerator Mass Spectrometry. We will present initial results of the data; showing that Wellington tree and Taranaki clean air trees compare well with the Wellington atmospheric record whereas trees growing downwind of the Vector plant demonstrate lower 14C content consistent with fossil CO2 addition. We compare historic CO2ff emissions as sampled by the trees with reported emissions from the Vector plant to quantify and evaluate the ability of the technique to monitor changes in fossil CO2 emissions. We demonstrate how this technique could be applied alongside complimentary methods to evaluate fossil CO2 emissions at point sources worldwide to determine compliance of CO2 emitters with emission reduction

  15. A "carbonizing dragon": China's fast growing CO2 emissions revisited.

    PubMed

    Minx, Jan C; Baiocchi, Giovanni; Peters, Glen P; Weber, Christopher L; Guan, Dabo; Hubacek, Klaus

    2011-11-01

    China's annual CO(2) emissions grew by around 4 billion tonnes between 1992 and 2007. More than 70% of this increase occurred between 2002 and 2007. While growing export demand contributed more than 50% to the CO(2) emission growth between 2002 and 2005, capital investments have been responsible for 61% of emission growth in China between 2005 and 2007. We use structural decomposition analysis to identify the drivers for China's emission growth between 1992 and 2007, with special focus on the period 2002 to 2007 when growth was most rapid. In contrast to previous analysis, we find that efficiency improvements have largely offset additional CO(2) emissions from increased final consumption between 2002 and 2007. The strong increases in emissions growth between 2002 and 2007 are instead explained by structural change in China's economy, which has newly emerged as the third major emission driver. This structural change is mainly the result of capital investments, in particular, the growing prominence of construction services and their carbon intensive supply chain. By closing the model for capital investment, we can now show that the majority of emissions embodied in capital investment are utilized for domestic household and government consumption (35-49% and 19-36%, respectively) with smaller amounts for the production of exports (21-31%). Urbanization and the associated changes in lifestyle are shown to be more important than other socio-demographic drivers like the decreasing household size or growing population. We argue that mitigation efforts will depend on the future development of these key drivers, particularly capital investments which dictate future mitigation costs. PMID:21888374

  16. Modeling global atmospheric CO2 with improved emission inventories and CO2 production from the oxidation of other carbon species

    SciTech Connect

    Nassar, Ray; Jones, DBA; Suntharalingam, P; Chen, j.; Andres, Robert Joseph; Wecht, K. J.; Yantosca, R. M.; Kulawik, SS; Bowman, K; Worden, JR; Machida, T; Matsueda, H

    2010-01-01

    The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth s carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (0.19 PgC yr 1), 3-D spatially-distributed emissions from aviation (0.16 PgC yr 1), and 3-D chemical production of CO2 (1.05 PgC yr 1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an associated surface correction for inventories that have counted emissions of CO2 precursors as CO2. We also explore the benefit of assimilating satellite observations of CO into GEOS-Chem to obtain an observation-based estimate of the CO2 chemical source. The CO assimilation corrects for an underestimate of atmospheric CO abundances in the model, resulting in increases of as much as 24% in the chemical source during May June 2006, and increasing the global annual estimate of CO2 chemical production from 1.05 to 1.18 Pg C. Comparisons of model CO2 with measurements are carried out in order to investigate the spatial and temporal distributions that result when these new sources are added. Inclusion of CO2 emissions from shipping and aviation are shown to increase the global CO2 latitudinal gradient by just over 0.10 ppm (3%), while the inclusion of CO2 chemical production (and the surface correction) is shown to decrease the latitudinal gradient by about 0.40 ppm (10%) with a complex spatial structure

  17. Large CO2 effluxes at night and during synoptic weather events significantly contribute to CO2 emissions from a reservoir

    NASA Astrophysics Data System (ADS)

    Liu, Heping; Zhang, Qianyu; Katul, Gabriel G.; Cole, Jonathan J.; Chapin, F. Stuart, III; MacIntyre, Sally

    2016-06-01

    CO2 emissions from inland waters are commonly determined by indirect methods that are based on the product of a gas transfer coefficient and the concentration gradient at the air water interface (e.g., wind-based gas transfer models). The measurements of concentration gradient are typically collected during the day in fair weather throughout the course of a year. Direct measurements of eddy covariance CO2 fluxes from a large inland water body (Ross Barnett reservoir, Mississippi, USA) show that CO2 effluxes at night are approximately 70% greater than those during the day. At longer time scales, frequent synoptic weather events associated with extratropical cyclones induce CO2 flux pulses, resulting in further increase in annual CO2 effluxes by 16%. Therefore, CO2 emission rates from this reservoir, if these diel and synoptic processes are under-sampled, are likely to be underestimated by approximately 40%. Our results also indicate that the CO2 emission rates from global inland waters reported in the literature, when based on indirect methods, are likely underestimated. Field samplings and indirect modeling frameworks that estimate CO2 emissions should account for both daytime–nighttime efflux difference and enhanced emissions during synoptic weather events. The analysis here can guide carbon emission sampling to improve regional carbon estimates.

  18. Large CO2 effluxes at night and during synoptic weather events significantly contribute to CO2 emissions from a reservoir

    NASA Astrophysics Data System (ADS)

    Liu, Heping; Zhang, Qianyu; Katul, Gabriel G.; Cole, Jonathan J.; Chapin, F. Stuart, III; MacIntyre, Sally

    2016-06-01

    CO2 emissions from inland waters are commonly determined by indirect methods that are based on the product of a gas transfer coefficient and the concentration gradient at the air water interface (e.g., wind-based gas transfer models). The measurements of concentration gradient are typically collected during the day in fair weather throughout the course of a year. Direct measurements of eddy covariance CO2 fluxes from a large inland water body (Ross Barnett reservoir, Mississippi, USA) show that CO2 effluxes at night are approximately 70% greater than those during the day. At longer time scales, frequent synoptic weather events associated with extratropical cyclones induce CO2 flux pulses, resulting in further increase in annual CO2 effluxes by 16%. Therefore, CO2 emission rates from this reservoir, if these diel and synoptic processes are under-sampled, are likely to be underestimated by approximately 40%. Our results also indicate that the CO2 emission rates from global inland waters reported in the literature, when based on indirect methods, are likely underestimated. Field samplings and indirect modeling frameworks that estimate CO2 emissions should account for both daytime-nighttime efflux difference and enhanced emissions during synoptic weather events. The analysis here can guide carbon emission sampling to improve regional carbon estimates.

  19. Large CO2 effluxes at night and during synoptic weather events significantly contribute to CO2 emissions from a reservoir

    DOE PAGES

    Liu, Heping; Zhang, Qianyu; Katul, Gabriel G.; Cole, Jonathan J.; Chapin, III, F. Stuart; MacIntyre, Sally

    2016-05-24

    CO2 emissions from inland waters are commonly determined by indirect methods that are based on the product of a gas transfer coefficient and the concentration gradient at the air water interface (e.g., wind-based gas transfer models). The measurements of concentration gradient are typically collected during the day in fair weather throughout the course of a year. Direct measurements of eddy covariance CO2 fluxes from a large inland water body (Ross Barnett reservoir, Mississippi, USA) show that CO2 effluxes at night are approximately 70% greater than those during the day. At longer time scales, frequent synoptic weather events associated with extratropicalmore » cyclones induce CO2 flux pulses, resulting in further increase in annual CO2 effluxes by 16%. Therefore, CO2 emission rates from this reservoir, if these diel and synoptic processes are under-sampled, are likely to be underestimated by approximately 40%. Our results also indicate that the CO2 emission rates from global inland waters reported in the literature, when based on indirect methods, are likely underestimated. Field samplings and indirect modeling frameworks that estimate CO2 emissions should account for both daytime-nighttime efflux difference and enhanced emissions during synoptic weather events. Furthermore, the analysis here can guide carbon emission sampling to improve regional carbon estimates.« less

  20. Reduction of CO2 to methanol using aluminum ester FLPs

    DOE PAGES

    Smythe, Nathan C.; Dixon, David A.; Garner, III, Edward B.; Rickard, Meredith M.; Mendez, Mariano; Scott, Brian Lindley; Zelenay, Barbara; Sutton, Andrew D.

    2015-10-09

    Herein we report the synthesis of Al-based esters containing halogenated benzene rings. These Lewis acids were paired with phosphines to form frustrated Lewis pairs (FLPs) which could subsequently bind CO2. While these FLPs were not sufficiently water-stable to catalyze the reduction of CO2 to MeOH using NH3BH3 as the reductant, we examine the effect of varying Lewis acid strength. Frustrated Lewis pairs (FLPs) are combinations of Lewis acids and Lewis bases where the acid and base are either sterically or geometrically restricted from interacting as strongly as their electronic structures would allow. This effect leads to enhanced reactivity towards smallmore » molecules and, consequently, interest in their potential as metal-free catalysts [1], [2], [3], [4] and [5]. Furthermore, to-date, the biggest success has been based around the ability of a myriad of systems to heterolytically cleave H2 and perform catalytic hydrogenations [2] and [3].« less

  1. Electrocatalysis of CO2 Reduction in Brush Polymer Ion Gels.

    PubMed

    McNicholas, Brendon J; Blakemore, James D; Chang, Alice B; Bates, Christopher M; Kramer, Wesley W; Grubbs, Robert H; Gray, Harry B

    2016-09-01

    The electrochemical characterization of brush polymer ion gels containing embedded small-molecule redox-active species is reported. Gels comprising PS-PEO-PS triblock brush polymer, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIm-TFSI), and some combination of ferrocene (Fc), cobaltocenium (CoCp2(+)), and Re(bpy)(CO)3Cl (1) exhibit diffusion-controlled redox processes with diffusion coefficients approximately one-fifth of those observed in neat BMIm-TFSI. Notably, 1 dissolves homogeneously in the interpenetrating matrix domain of the ion gel and displays electrocatalytic CO2 reduction to CO in the gel. The catalytic wave exhibits a positive shift versus Fc(+/0) compared with analogous nonaqueous solvents with a reduction potential 450 mV positive of onset and 90% Faradaic efficiency for CO production. These materials provide a promising and alternative approach to immobilized electrocatalysis, creating numerous opportunities for application in solid-state devices.

  2. A growing commitment to future CO2 emissions

    NASA Astrophysics Data System (ADS)

    Damon Matthews, H.

    2014-11-01

    The construction of new fossil fuel energy infrastructure implies a commitment to burn fossil fuels and therefore produce CO2 emissions for several decades into the future. The recent letter by Davis and Socolow (2014 Environ. Res. Lett. 9 084018) highlights the current and growing commitment to future emissions, and argues that this emission commitment should be accounted for at the time of new construction. The idea of accounting for future committed emissions associated with current energy policy decisions is compelling and could equally be applied to other aspects of the fossil fuel supply chain, such as investing in the development of new fossil fuel reserves. There is evidence, for example, that oil reserves are growing faster that the rate of extraction, implying a growing future emissions commitment that is likely incompatible with climate mitigation targets.

  3. Misrepresentation of the IPCC CO2 emission scenarios

    SciTech Connect

    Manning, Martin; Edmonds, James A.; Emori, S.; Grubler, Arnulf; Hibbard, Kathleen A.; Joos, Fortunat; Kainuma, M.; Keeling, Ralph; Kram, Tom; Manning, Andrew; Meinhausen, Malte; Moss, Richard H.; Nakicenovic, Nebojsa; Riahi, Keywan; Rose, Steven K.; Smith, Steven J.; Swart, Robert; Van Vuuren, Detlef

    2010-06-01

    Estimates of recent fossil fuel CO2 emissions have been compared with the IPCC SRES (Special Report on Emission Scenarios) emission scenarios that had been developed for analysis of future climate change, impacts and mitigation. In some cases this comparison uses averages across subgroups of SRES scenarios and for one category of greenhouse gases (industrial sources of CO2). That approach can be misleading and cause confusion as it is inconsistent with many of the papers on future climate change projections that are based on a specific subset of closely scrutinized SRES scenarios, known as illustrative marker scenarios. Here, we show that comparison between recent estimates of fossil fuel emissions trends and the SRES illustrative marker scenarios leads to the conclusion that recent trends are not outside the SRES range. Furthermore, the recent economic downturn appears to have brought actual emission back toward the middle of the SRES illustrative marker scenarios. We also note that SRES emission scenarios are designed to reflect potential alternative long-term trends in a world without climate policy intervention and the trend in the resulting climate change is not sensitive to short-term fluctuations.

  4. Multiscale observations of CO2, 13CO2, and pollutants at Four Corners for emission verification and attribution.

    PubMed

    Lindenmaier, Rodica; Dubey, Manvendra K; Henderson, Bradley G; Butterfield, Zachary T; Herman, Jay R; Rahn, Thom; Lee, Sang-Hyun

    2014-06-10

    There is a pressing need to verify air pollutant and greenhouse gas emissions from anthropogenic fossil energy sources to enforce current and future regulations. We demonstrate the feasibility of using simultaneous remote sensing observations of column abundances of CO2, CO, and NO2 to inform and verify emission inventories. We report, to our knowledge, the first ever simultaneous column enhancements in CO2 (3-10 ppm) and NO2 (1-3 Dobson Units), and evidence of δ(13)CO2 depletion in an urban region with two large coal-fired power plants with distinct scrubbing technologies that have resulted in ∆NOx/∆CO2 emission ratios that differ by a factor of two. Ground-based total atmospheric column trace gas abundances change synchronously and correlate well with simultaneous in situ point measurements during plume interceptions. Emission ratios of ∆NOx/∆CO2 and ∆SO2/∆CO2 derived from in situ atmospheric observations agree with those reported by in-stack monitors. Forward simulations using in-stack emissions agree with remote column CO2 and NO2 plume observations after fine scale adjustments. Both observed and simulated column ∆NO2/∆CO2 ratios indicate that a large fraction (70-75%) of the region is polluted. We demonstrate that the column emission ratios of ∆NO2/∆CO2 can resolve changes from day-to-day variation in sources with distinct emission factors (clean and dirty power plants, urban, and fires). We apportion these sources by using NO2, SO2, and CO as signatures. Our high-frequency remote sensing observations of CO2 and coemitted pollutants offer promise for the verification of power plant emission factors and abatement technologies from ground and space.

  5. Multiscale observations of CO2, 13CO2, and pollutants at Four Corners for emission verification and attribution.

    PubMed

    Lindenmaier, Rodica; Dubey, Manvendra K; Henderson, Bradley G; Butterfield, Zachary T; Herman, Jay R; Rahn, Thom; Lee, Sang-Hyun

    2014-06-10

    There is a pressing need to verify air pollutant and greenhouse gas emissions from anthropogenic fossil energy sources to enforce current and future regulations. We demonstrate the feasibility of using simultaneous remote sensing observations of column abundances of CO2, CO, and NO2 to inform and verify emission inventories. We report, to our knowledge, the first ever simultaneous column enhancements in CO2 (3-10 ppm) and NO2 (1-3 Dobson Units), and evidence of δ(13)CO2 depletion in an urban region with two large coal-fired power plants with distinct scrubbing technologies that have resulted in ∆NOx/∆CO2 emission ratios that differ by a factor of two. Ground-based total atmospheric column trace gas abundances change synchronously and correlate well with simultaneous in situ point measurements during plume interceptions. Emission ratios of ∆NOx/∆CO2 and ∆SO2/∆CO2 derived from in situ atmospheric observations agree with those reported by in-stack monitors. Forward simulations using in-stack emissions agree with remote column CO2 and NO2 plume observations after fine scale adjustments. Both observed and simulated column ∆NO2/∆CO2 ratios indicate that a large fraction (70-75%) of the region is polluted. We demonstrate that the column emission ratios of ∆NO2/∆CO2 can resolve changes from day-to-day variation in sources with distinct emission factors (clean and dirty power plants, urban, and fires). We apportion these sources by using NO2, SO2, and CO as signatures. Our high-frequency remote sensing observations of CO2 and coemitted pollutants offer promise for the verification of power plant emission factors and abatement technologies from ground and space. PMID:24843169

  6. 40 CFR 75.13 - Specific provisions for monitoring CO2 emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Specific provisions for monitoring CO2... monitoring CO2 emissions. (a) CO 2 continuous emission monitoring system. If the owner or operator chooses to... operating requirements in § 75.10 for a CO2 continuous emission monitoring system and flow monitoring...

  7. 40 CFR 75.13 - Specific provisions for monitoring CO2 emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Specific provisions for monitoring CO2... monitoring CO2 emissions. (a) CO 2 continuous emission monitoring system. If the owner or operator chooses to... operating requirements in § 75.10 for a CO2 continuous emission monitoring system and flow monitoring...

  8. Atmospheric inversion for cost effective quantification of city CO2 emissions

    NASA Astrophysics Data System (ADS)

    Wu, L.; Broquet, G.; Ciais, P.; Bellassen, V.; Vogel, F.; Chevallier, F.; Xueref-Remy, I.; Wang, Y.

    2015-11-01

    uncertainty that is two times larger than the target of 5 %. By extending the network from 10 to 70 stations, the inversion can meet this requirement. As for major sectoral CO2 emissions, the uncertainties in the inverted emissions using 70 stations are reduced significantly over that obtained using 10 stations by 32 % for commercial and residential buildings, by 33 % for road transport and by 18 % for the production of energy by power plants, respectively. With 70 stations, the uncertainties from the inversion become of 15 % 2-sigma annual uncertainty for dispersed building emissions, and 18 % for emissions from road transport and energy production. The inversion performance could be further improved by optimal design of station locations and/or by assimilating additional atmospheric measurements of species that are co-emitted with CO2 by fossil fuel combustion processes with a specific signature from each sector, such as carbon monoxide (CO). Atmospheric inversions based on continuous CO2 measurements from a large number of cheap sensors can thus deliver a valuable quantification tool for the monitoring and/or the verification of city CO2 emissions (baseline) and CO2 emission reductions (commitments).

  9. Detecting small scale CO2 emission structures using OCO-2

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Eldering, Annmarie; Verhulst, Kristal R.; Miller, Charles E.; Nguyen, Hai M.; Oda, Tomohiro; O'Dell, Christopher; Rao, Preeti; Kahn, Brian; Crisp, David; Gunson, Michael R.; Sanchez, Robert M.; Ashok, Manasa; Pieri, David; Linick, Justin P.; Yuen, Karen

    2016-04-01

    Localized carbon dioxide (CO2) emission structures cover spatial domains of less than 50 km diameter and include cities and transportation networks, as well as fossil fuel production, upgrading and distribution infra-structure. Anthropogenic sources increasingly upset the natural balance between natural carbon sources and sinks. Mitigation of resulting climate change impacts requires management of emissions, and emissions management requires monitoring, reporting and verification. Space-borne measurements provide a unique opportunity to detect, quantify, and analyze small scale and point source emissions on a global scale. NASA's first satellite dedicated to atmospheric CO2 observation, the July 2014 launched Orbiting Carbon Observatory (OCO-2), now leads the afternoon constellation of satellites (A-Train). Its continuous swath of 2 to 10 km in width and eight footprints across can slice through coincident emission plumes and may provide momentary cross sections. First OCO-2 results demonstrate that we can detect localized source signals in the form of urban total column averaged CO2 enhancements of ~2 ppm against suburban and rural backgrounds. OCO-2's multi-sounding swath observing geometry reveals intra-urban spatial structures reflected in XCO2 data, previously unobserved from space. The transition from single-shot GOSAT soundings detecting urban/rural differences (Kort et al., 2012) to hundreds of soundings per OCO-2 swath opens up the path to future capabilities enabling urban tomography of greenhouse gases. For singular point sources like coal fired power plants, we have developed proxy detections of plumes using bands of imaging spectrometers with sensitivity to SO2 in the thermal infrared (ASTER). This approach provides a means to automate plume detection with subsequent matching and mining of OCO-2 data for enhanced detection efficiency and validation. © California Institute of Technology

  10. CO2 Emissions Generated by a Fall AGU Meeting

    NASA Astrophysics Data System (ADS)

    osborn, G.; Malowany, K. S.; Samolczyk, M. A.

    2011-12-01

    The process of reporting on and discussing geophysical phenomena, including emissions of greenhouse gases, generates more greenhouse gases. At the 2010 fall meeting of the AGU, 19,175 delegates from 81 countries, including, for example, Eritrea, Nepal, and Tanzania, traveled a total of 156,000,000 km to congregate in San Francisco for five days. With data on home bases of participants provided by AGU, we estimated the CO2 emissions generated by travel and hotel stays of those participants. The majority of the emissions from the meeting resulted from air travel . In order to estimate the footprint of such travel, (a) distances from the largest airport in each country and American state (except Canada and California) to San Francisco were tabulated , (b) basic distances were converted to emissions using the TerraPass (TRX Travel Analytics) carbon calculator, (c) it was assumed that half the California participants would fly and half would drive, (d) it was assumed that half of Canadians would fly out of Toronto and half out of Vancouver, and (e) a fudge factor of 10% was added to air travel emissions to account for connecting flights made by some participants to the main airports in the respective countries (connecting flights are disproportionately significant because of high output during takeoff acceleration). Driving impacts were estimated with a Transport Direct/RAC Motoring Services calculator using a 2006 Toyota Corolla as a standard car. An average driving distance of 50 km to the departure airport, and from the airport upon return, was assumed. Train impacts were estimated using the assumption that all flying participants would take BART from SFO. Accomodation impacts were estimated using an Environmental Protection Agency calculator, an assumed average stay of 3 nights, and the assumption that 500 participants commuted from local residences or stayed with friends. The above assumptions lead to an estimate, which we consider conservative, of 19 million kg of

  11. Climate, CO2, and demographic impacts on global wildfire emissions

    NASA Astrophysics Data System (ADS)

    Knorr, W.; Jiang, L.; Arneth, A.

    2015-09-01

    Wildfires are by far the largest contributor to global biomass burning and constitute a large global source of atmospheric traces gases and aerosols. Such emissions have a considerable impact on air quality and constitute a major health hazard. Biomass burning also influences the radiative balance of the atmosphere and is thus not only of societal, but also of significant scientific interest. There is a common perception that climate change will lead to an increase in emissions as hot and dry weather events that promote wildfire will become more common. However, even though a few studies have found that the inclusion of CO2 fertilization of photosynthesis and changes in human population patterns will tend to somewhat lower predictions of future wildfire emissions, no such study has included full ensemble ranges of both climate predictions and population projections, including the effect of different degrees of urbanisation. Here, we present a series of 124 simulations with the LPJ-GUESS-SIMFIRE global dynamic vegetation - wildfire model, including a semi-empirical formulation for the prediction of burned area based on fire weather, fuel continuity and human population density. The simulations comprise Climate Model Intercomparison Project 5 (CMIP5) climate predictions from eight Earth system models using two Representative Concentration Pathways (RCPs) and five scenarios of future human population density based on the series of Shared Socioeconomic Pathways (SSPs), sensitivity tests for the effect of climate and CO2, as well as a sensitivity analysis using two alternative parameterisations of the semi-empirical burned-area model. Contrary to previous work, we find no clear future trend of global wildfire emissions for the moderate emissions and climate change scenario based on the RCP 4.5. Only historical population change introduces a decline by around 15 % since 1900. Future emissions could either increase for low population growth and fast urbanisation, or

  12. An estimate of monthly global emissions of anthropogenic CO2: Impact on the seasonal cycle of atmospheric CO2

    SciTech Connect

    Erickson, D; Mills, R; Gregg, J; Blasing, T J; Hoffman, F; Andres, Robert Joseph; Devries, M; Zhu, Z; Kawa, S

    2008-01-01

    Monthly estimates of the global emissions of anthropogenic CO2 are presented. Approximating the seasonal CO2 emission cycle using a 2-harmonic Fourier series with coefficients as a function of latitude, the annual fluxes are decomposed into monthly flux estimates based on data for the United States and applied globally. These monthly anthropogenic CO2 flux estimates are then used to model atmospheric CO2 concentrations using meteorological fields from the NASA GEOS-4 data assimilation system. We find that the use of monthly resolved fluxes makes a significant difference in the seasonal cycle of atmospheric CO2 in and near those regions where anthropogenic CO2 is released to the atmosphere. Local variations of 2-6 ppmv CO2 in the seasonal cycle amplitude are simulated; larger variations would be expected if smaller source-receptor distances could be more precisely specified using a more refined spatial resolution. We also find that in the midlatitudes near the sources, synoptic scale atmospheric circulations are important in the winter and that boundary layer venting and diurnal rectifier effects are more important in the summer. These findings have implications for inverse-modeling efforts that attempt to estimate surface source/sink regions especially when the surface sinks are colocated with regions of strong anthropogenic CO2 emissions.

  13. Urban CO2 emissions metabolism: The Hestia Project

    NASA Astrophysics Data System (ADS)

    Gurney, K. R.; Razlivanov, I.; Zhou, Y.; Song, Y.

    2011-12-01

    A central expression of urban metabolism is the consumption of energy and the resulting environmental impact, particularly the emission of CO2 and other greenhouse gases. Quantification of energy and emissions has been performed for numerous cities but rarely has this been done in explicit space/time detail. Here, we present the Hestia Project, an effort aimed at building a high resolution (eg. building and road link-specific, hourly) fossil fuel CO2 emissions data product for the urban domain. A complete data product has been built for the city of Indianapolis and work is ongoing for the city of Los Angeles (Figure 1). The effort in Indianapolis is now part of a larger effort aimed at a convergent top-down/bottom-up assessment of greenhouse gas emissions, called INFLUX. Our urban-level quantification relies on a mixture of data and modeling structures. We start with the sector-specific Vulcan Project estimate at the mix of geocoded and county-wide levels. The Hestia aim is to distribute the Vulcan result in space and time. Two components take the majority of effort: buildings and onroad emissions. For the buildings, we utilize an energy building model which we constrain through lidar data, county assessor parcel data and GIS layers. For onroad emissions, we use a combination of traffic data and GIS road layers maintaining vehicle class information. Finally, all pointwise data in the Vulcan Project are transferred to our urban landscape and additional time distribution is performed. A key benefit of the approach taken in this study is the tracking and archiving of fuel and process-level detail (eg. combustion process, other pollutants), allowing for a more thorough understanding and analysis of energy throughputs in the urban environment. Next steps in this research from the metabolism perspective is to consider the carbon footprint of material goods and their lateral transfer in addition to the connection between electricity consumption and production.

  14. Continued global warming after CO2 emissions stoppage

    NASA Astrophysics Data System (ADS)

    Frölicher, Thomas; Winton, Michael; Sarmiento, Jorge

    2014-05-01

    Recent studies have suggested that global mean surface temperature would remain approximately constant on multi-century timescales after CO2 emissions are stopped. Here we use Earth system model simulations of such a stoppage to demonstrate that in some models, surface temperature may actually increase on multi-century timescales after an initial century-long decrease. For example, global mean surface temperature may increase by 0.6°C after a carbon emissions stoppage at 2-degree. This increase occurs in spite of a decline in radiative forcing that exceeds the decline in ocean heat uptake—a circumstance that would otherwise be expected to lead to a decline in global temperature. The reason is that the warming effect of decreasing ocean heat uptake together with feedback effects arising in response to the geographic structure of ocean heat uptake overcompensates the cooling effect of decreasing atmospheric CO2 on multi-century timescales. Our study also reveals that equilibrium climate sensitivity estimates based on a widely used method of regressing the Earth's energy imbalance against surface temperature change are biased. Uncertainty in the magnitude of the feedback effects associated with the magnitude and geographic distribution of ocean heat uptake therefore contributes substantially to the uncertainty in allowable carbon emissions for a given multi-century warming target.

  15. The relationship between economic growth, energy consumption, and CO2 emissions: Empirical evidence from China.

    PubMed

    Wang, Shaojian; Li, Qiuying; Fang, Chuanglin; Zhou, Chunshan

    2016-01-15

    Following several decades of rapid economic growth, China has become the largest energy consumer and the greatest emitter of CO2 in the world. Given the complex development situation faced by contemporary China, Chinese policymakers now confront the dual challenge of reducing energy use while continuing to foster economic growth. This study posits that a better understanding of the relationship between economic growth, energy consumption, and CO2 emissions is necessary, in order for the Chinese government to develop the energy saving and emission reduction strategies for addressing the impacts of climate change. This paper investigates the cointegrating, temporally dynamic, and casual relationships that exist between economic growth, energy consumption, and CO2 emissions in China, using data for the period 1990-2012. The study develops a comprehensive conceptual framework in order to perform this analysis. The results of cointegration tests suggest the existence of long-run cointegrating relationship among the variables, albeit with short dynamic adjustment mechanisms, indicating that the proportion of disequilibrium errors that can be adjusted in the next period will account for only a fraction of the changes. Further, impulse response analysis (which describes the reaction of any variable as a function of time in response to external shocks) found that the impact of a shock in CO2 emissions on economic growth or energy consumption was only marginally significant. Finally, Granger casual relationships were found to exist between economic growth, energy consumption, and CO2 emissions; specifically, a bi-directional causal relationship between economic growth and energy consumption was identified, and a unidirectional causal relationship was found to exist from energy consumption to CO2 emissions. The findings have significant implications for both academics and practitioners, warning of the need to develop and implement long-term energy and economic policies in

  16. Electrochemical CO2 Reduction to Hydrocarbons on a Heterogeneous Molecular Cu Catalyst in Aqueous Solution.

    PubMed

    Weng, Zhe; Jiang, Jianbing; Wu, Yueshen; Wu, Zishan; Guo, Xiaoting; Materna, Kelly L; Liu, Wen; Batista, Victor S; Brudvig, Gary W; Wang, Hailiang

    2016-07-01

    Exploration of heterogeneous molecular catalysts combining the atomic-level tunability of molecular structures and the practical handling advantages of heterogeneous catalysts represents an attractive approach to developing high-performance catalysts for important and challenging chemical reactions such as electrochemical carbon dioxide reduction which holds the promise for converting emissions back to fuels utilizing renewable energy. Thus, far, efficient and selective electroreduction of CO2 to deeply reduced products such as hydrocarbons remains a big challenge. Here, we report a molecular copper-porphyrin complex (copper(II)-5,10,15,20-tetrakis(2,6-dihydroxyphenyl)porphyrin) that can be used as a heterogeneous electrocatalyst with high activity and selectivity for reducing CO2 to hydrocarbons in aqueous media. At -0.976 V vs the reversible hydrogen electrode, the catalyst is able to drive partial current densities of 13.2 and 8.4 mA cm(-2) for methane and ethylene production from CO2 reduction, corresponding to turnover frequencies of 4.3 and 1.8 molecules·site(-1)·s(-1) for methane and ethylene, respectively. This represents the highest catalytic activity to date for hydrocarbon production over a molecular CO2 reduction electrocatalyst. The unprecedented catalytic performance is attributed to the built-in hydroxyl groups in the porphyrin structure and the reactivity of the copper(I) metal center. PMID:27310487

  17. Electrochemical CO2 Reduction to Hydrocarbons on a Heterogeneous Molecular Cu Catalyst in Aqueous Solution.

    PubMed

    Weng, Zhe; Jiang, Jianbing; Wu, Yueshen; Wu, Zishan; Guo, Xiaoting; Materna, Kelly L; Liu, Wen; Batista, Victor S; Brudvig, Gary W; Wang, Hailiang

    2016-07-01

    Exploration of heterogeneous molecular catalysts combining the atomic-level tunability of molecular structures and the practical handling advantages of heterogeneous catalysts represents an attractive approach to developing high-performance catalysts for important and challenging chemical reactions such as electrochemical carbon dioxide reduction which holds the promise for converting emissions back to fuels utilizing renewable energy. Thus, far, efficient and selective electroreduction of CO2 to deeply reduced products such as hydrocarbons remains a big challenge. Here, we report a molecular copper-porphyrin complex (copper(II)-5,10,15,20-tetrakis(2,6-dihydroxyphenyl)porphyrin) that can be used as a heterogeneous electrocatalyst with high activity and selectivity for reducing CO2 to hydrocarbons in aqueous media. At -0.976 V vs the reversible hydrogen electrode, the catalyst is able to drive partial current densities of 13.2 and 8.4 mA cm(-2) for methane and ethylene production from CO2 reduction, corresponding to turnover frequencies of 4.3 and 1.8 molecules·site(-1)·s(-1) for methane and ethylene, respectively. This represents the highest catalytic activity to date for hydrocarbon production over a molecular CO2 reduction electrocatalyst. The unprecedented catalytic performance is attributed to the built-in hydroxyl groups in the porphyrin structure and the reactivity of the copper(I) metal center.

  18. Trophic-level dependent effects on CO2 emissions from experimental stream ecosystems.

    PubMed

    Atwood, Trisha B; Hammill, Edd; Richardson, John S

    2014-11-01

    Concern over accelerating rates of species invasions and losses have initiated investigations into how local and global changes to predator abundance mediate trophic cascades that influence CO2 fluxes of aquatic ecosystems. However, to date, no studies have investigated how species additions or losses at other consumer trophic levels influence the CO2 flux of aquatic ecosystems. In this study, we added a large predatory stonefly, detritivorous stonefly, or grazer tadpole to experimental stream food webs and over a 70-day period quantified their effects on community composition, leaf litter decomposition, chlorophyll-a concentrations, and stream CO2 emissions. In general, streams where the large grazer or large detritivore were added showed no change in total invertebrate biomass, leaf litter loss, chlorophyll-a concentrations, or stream CO2 emissions compared with controls; although we did observe a spike in CO2 emissions in the large grazer treatment following a substantial reduction in chlorophyll-a concentrations on day 28. However, the large grazer and large detritivore altered the community composition of streams by reducing the densities of other grazer and detritivore taxa, respectively, compared with controls. Conversely, the addition of the large predator created trophic cascades that reduced total invertebrate biomass and increased primary producer biomass. The cascading effects of the predator additions on the food web ultimately led to decreased CO2 emissions from stream channels by up to 95%. Our results suggest that stream ecosystem processes were more influenced by changes in large predator abundance than large grazer or detritivore abundance, because of a lack of functionally similar large predators. Our study demonstrates that the presence/absence of species with unique functional roles may have consequences for the exchange of CO2 between the ecosystem and the atmosphere.

  19. Impacts of potential CO2-reduction policies on air quality in the United States.

    PubMed

    Trail, Marcus A; Tsimpidi, Alexandra P; Liu, Peng; Tsigaridis, Kostas; Hu, Yongtao; Rudokas, Jason R; Miller, Paul J; Nenes, Athanasios; Russell, Armistead G

    2015-04-21

    Impacts of emissions changes from four potential U.S. CO2 emission reduction policies on 2050 air quality are analyzed using the community multiscale air quality model (CMAQ). Future meteorology was downscaled from the Goddard Institute for Space Studies (GISS) ModelE General Circulation Model (GCM) to the regional scale using the Weather Research Forecasting (WRF) model. We use emissions growth factors from the EPAUS9r MARKAL model to project emissions inventories for two climate tax scenarios, a combined transportation and energy scenario, a biomass energy scenario and a reference case. Implementation of a relatively aggressive carbon tax leads to improved PM2.5 air quality compared to the reference case as incentives increase for facilities to install flue-gas desulfurization (FGD) and carbon capture and sequestration (CCS) technologies. However, less capital is available to install NOX reduction technologies, resulting in an O3 increase. A policy aimed at reducing CO2 from the transportation sector and electricity production sectors leads to reduced emissions of mobile source NOX, thus reducing O3. Over most of the U.S., this scenario leads to reduced PM2.5 concentrations. However, increased primary PM2.5 emissions associated with fuel switching in the residential and industrial sectors leads to increased organic matter (OM) and PM2.5 in some cities. PMID:25811418

  20. Impacts of potential CO2-reduction policies on air quality in the United States.

    PubMed

    Trail, Marcus A; Tsimpidi, Alexandra P; Liu, Peng; Tsigaridis, Kostas; Hu, Yongtao; Rudokas, Jason R; Miller, Paul J; Nenes, Athanasios; Russell, Armistead G

    2015-04-21

    Impacts of emissions changes from four potential U.S. CO2 emission reduction policies on 2050 air quality are analyzed using the community multiscale air quality model (CMAQ). Future meteorology was downscaled from the Goddard Institute for Space Studies (GISS) ModelE General Circulation Model (GCM) to the regional scale using the Weather Research Forecasting (WRF) model. We use emissions growth factors from the EPAUS9r MARKAL model to project emissions inventories for two climate tax scenarios, a combined transportation and energy scenario, a biomass energy scenario and a reference case. Implementation of a relatively aggressive carbon tax leads to improved PM2.5 air quality compared to the reference case as incentives increase for facilities to install flue-gas desulfurization (FGD) and carbon capture and sequestration (CCS) technologies. However, less capital is available to install NOX reduction technologies, resulting in an O3 increase. A policy aimed at reducing CO2 from the transportation sector and electricity production sectors leads to reduced emissions of mobile source NOX, thus reducing O3. Over most of the U.S., this scenario leads to reduced PM2.5 concentrations. However, increased primary PM2.5 emissions associated with fuel switching in the residential and industrial sectors leads to increased organic matter (OM) and PM2.5 in some cities.

  1. Enhancement of farmland greenhouse gas emissions from leakage of stored CO2: simulation of leaked CO2 from CCS.

    PubMed

    Zhang, Xueyan; Ma, Xin; Wu, Yang; Li, Yue

    2015-06-15

    The effects of leaked CO2 on plant and soil constitute a key objective of carbon capture and storage (CCS) safety. The effects of leaked CO2 on trace soil gas (e.g., methane (CH4) and nitrous oxide (N2O) emissions in farmlands are not well-understood. This study simulated the effects of elevated soil CO2 on CH4 and N2O through pot experiments. The results revealed that significant increases of CH4 and N2O emissions were induced by the simulated CO2 leakages; the emission rates of CH4 and N2O were substantial, reaching about 222 and 48 times than that of the control, respectively. The absolute global warming potentials (GWPs) of the additional CH4 and N2O are considerable, but the cumulative GWPs of the additional CH4 and N2O only accounted for 0.03% and 0.06%, respectively, of the cumulative amount of leaked CO2 under high leakage conditions. The results demonstrate that leakage from CCS projects may lead to additional greenhouse gas emissions from soil; however, in general, the amount of additional CH4 and N2O emissions is negligible when compared with the amount of leaked CO2.

  2. Nitrogen and phosphorous limitations significantly reduce future allowable CO2 emissions

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Ying-Ping; Matear, Richard; Pitman, Andy; Dai, Yongjiu

    2014-05-01

    Earth System Models (ESMs) can be used to diagnose the emissions of CO2 allowed in order to follow the representative concentration pathways (RCPs) that are consistent with different climate scenarios. By mass balance, the allowable emission is calculated as the sum of the changes in atmospheric CO2, land and ocean carbon pools. Only two ESMs used in the fifth assessment (AR5) of International Panel on Climate Change (IPCC) include nitrogen (N) limitation, and none include phosphorous (P) limitation. In this study we quantified the effects of N and P limitations on the allowable emissions using an ESM simulating land and ocean CO2 exchanges to the atmosphere in RCPs used for IPCC AR5. The model can run with carbon cycle alone (C only), carbon and nitrogen (CN) or carbon, nitrogen and phosphorus (CNP) cycles as its land configurations. We used the simulated land and ocean carbon accumulation rates from 1850 to 2100 to diagnose the allowable emissions for each of three simulations (C only, CN or CNP). These were then compared with the emissions estimated by the Integrated Assessment Models (IAMs) used to generate RCP2.6 and RCP8.5. N and P limitations on land in our ESM led to systematically lower land carbon uptake, and thus reduced allowable emissions by 69 Pg C (21%) for RCP2.6, and by 250 Pg C (13%) for RCP8.5 from 2006 to 2100. Our results demonstrated that including N and P limitations requires a greater reduction in human CO2 emissions than assumed in the IAMs used to generate the RCPs. Reference: Zhang, Q., Y. P. Wang, R. J. Matear, A. J. Pitman, and Y. J. Dai (2014), Nitrogen and phosphorous limitations significantly reduce future allowable CO2 emissions, Geophys. Res. Lett., 41, doi:10.1002/2013GL058352.

  3. Reducing CO2 emissions and energy consumption of heat-integrated distillation systems.

    PubMed

    Gadalla, Mamdouh A; Olujic, Zarko; Jansens, Peter J; Jobson, Megan; Smith, Robin

    2005-09-01

    Distillation systems are energy and power intensive processes and contribute significantly to the greenhouse gases emissions (e.g. carbon dioxide). Reducing CO2 emissions is an absolute necessity and expensive challenge to the chemical process industries in orderto meetthe environmental targets as agreed in the Kyoto Protocol. A simple model for the calculation of CO2 emissions from heat-integrated distillation systems is introduced, considering typical process industry utility devices such as boilers, furnaces, and turbines. Furnaces and turbines consume large quantities of fuels to provide electricity and process heats. As a result, they produce considerable amounts of CO2 gas to the atmosphere. Boilers are necessary to supply steam for heating purposes; besides, they are also significant emissions contributors. The model is used in an optimization-based approach to optimize the process conditions of an existing crude oil atmospheric tower in order to reduce its CO2 emissions and energy demands. It is also applied to generate design options to reduce the emissions from a novel internally heat-integrated distillation column (HIDiC). A gas turbine can be integrated with these distillation systems for larger emissions reduction and further energy savings. Results show that existing crude oil installations can save up to 21% in energy and 22% in emissions, when the process conditions are optimized. Additionally, by integrating a gas turbine, the total emissions can be reduced further by 48%. Internal heat-integrated columns can be a good alternative to conventional heat pump and other energy intensive close boiling mixtures separations. Energy savings can reach up to 100% with respect to reboiler heat requirements. Emissions of these configurations are cut down by up to 83%, compared to conventional units, and by 36%, with respect to heat pump alternatives. Importantly, cost savings and more profit are gained in parallel to emissions minimization. PMID:16190250

  4. Reducing CO2 emissions and energy consumption of heat-integrated distillation systems.

    PubMed

    Gadalla, Mamdouh A; Olujic, Zarko; Jansens, Peter J; Jobson, Megan; Smith, Robin

    2005-09-01

    Distillation systems are energy and power intensive processes and contribute significantly to the greenhouse gases emissions (e.g. carbon dioxide). Reducing CO2 emissions is an absolute necessity and expensive challenge to the chemical process industries in orderto meetthe environmental targets as agreed in the Kyoto Protocol. A simple model for the calculation of CO2 emissions from heat-integrated distillation systems is introduced, considering typical process industry utility devices such as boilers, furnaces, and turbines. Furnaces and turbines consume large quantities of fuels to provide electricity and process heats. As a result, they produce considerable amounts of CO2 gas to the atmosphere. Boilers are necessary to supply steam for heating purposes; besides, they are also significant emissions contributors. The model is used in an optimization-based approach to optimize the process conditions of an existing crude oil atmospheric tower in order to reduce its CO2 emissions and energy demands. It is also applied to generate design options to reduce the emissions from a novel internally heat-integrated distillation column (HIDiC). A gas turbine can be integrated with these distillation systems for larger emissions reduction and further energy savings. Results show that existing crude oil installations can save up to 21% in energy and 22% in emissions, when the process conditions are optimized. Additionally, by integrating a gas turbine, the total emissions can be reduced further by 48%. Internal heat-integrated columns can be a good alternative to conventional heat pump and other energy intensive close boiling mixtures separations. Energy savings can reach up to 100% with respect to reboiler heat requirements. Emissions of these configurations are cut down by up to 83%, compared to conventional units, and by 36%, with respect to heat pump alternatives. Importantly, cost savings and more profit are gained in parallel to emissions minimization.

  5. Vehicle emissions of greenhouse gases and related tracers from a tunnel study: CO : CO2, N2O : CO2, CH4 : CO2, O2 : CO2 ratios, and the stable isotopes 13C and 18O in CO2 and CO

    NASA Astrophysics Data System (ADS)

    Popa, M. E.; Vollmer, M. K.; Jordan, A.; Brand, W. A.; Pathirana, S. L.; Rothe, M.; Röckmann, T.

    2014-02-01

    Measurements of CO2, CO, N2O and CH4 mole fractions, O2 / N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the Islisberg highway tunnel (Switzerland). The molar CO : CO2 ratios, with an average of (4.15 ± 0.34) ppb:ppm, are lower than reported in previous studies, pointing to a reduction in CO emissions from traffic. The 13C in CO2 reflects the isotopic composition of the fuel. 18O in CO2 is slightly depleted compared to the 18O in atmospheric O2, and shows significant variability. In contrast, the δ13C values of CO show that significant fractionation takes place during CO destruction in the catalytic converter. 13C in CO is enriched by 3‰ compared to the 13C in the fuel burnt, while the 18O content is similar to that of atmospheric O2. We compute a fractionation constant of (-2.7 ± 0.7)‰ for 13C during CO destruction. The N2O : CO2 average ratio of (1.8 ± 0.2) × 10-2 ppb:ppm is significantly lower than in past studies, showing a reduction in N2O emissions likely related to improvements in the catalytic converter technology. We also observed small CH4 emissions, with an average CH4 : CO2 ratio of (4.6 ± 0.2) × 10-2 ppb:ppm. The O2 : CO2 ratios of (-1.47 ± 0.01) ppm:ppm are very close to the expected, theoretically calculated values of O2 depletion per CO2 enhancement.

  6. Continued global warming after CO2 emissions stoppage

    NASA Astrophysics Data System (ADS)

    Frölicher, Thomas Lukas; Winton, Michael; Sarmiento, Jorge Louis

    2014-01-01

    Recent studies have suggested that global mean surface temperature would remain approximately constant on multi-century timescales after CO2 emissions are stopped. Here we use Earth system model simulations of such a stoppage to demonstrate that in some models, surface temperature may actually increase on multi-century timescales after an initial century-long decrease. This occurs in spite of a decline in radiative forcing that exceeds the decline in ocean heat uptake--a circumstance that would otherwise be expected to lead to a decline in global temperature. The reason is that the warming effect of decreasing ocean heat uptake together with feedback effects arising in response to the geographic structure of ocean heat uptake overcompensates the cooling effect of decreasing atmospheric CO2 on multi-century timescales. Our study also reveals that equilibrium climate sensitivity estimates based on a widely used method of regressing the Earth's energy imbalance against surface temperature change are biased. Uncertainty in the magnitude of the feedback effects associated with the magnitude and geographic distribution of ocean heat uptake therefore contributes substantially to the uncertainty in allowable carbon emissions for a given multi-century warming target.

  7. Understanding changes in the UK's CO2 emissions: a global perspective.

    PubMed

    Baiocchi, Giovanni; Minx, Jan C

    2010-02-15

    The UK appears to be a leading country in curbing greenhouse gas (GHG) emissions. Unlike many other developed countries, it has already met its Kyoto obligations and defined ambitious, legally binding targets for the future. Recently this achievement has been called into question as it ignores rapidly changing patterns of production and international trade. We use structural decomposition analysis (SDA) to investigate the drivers behind annual changes in CO(2) emission from consumption in the UK between 1992 and 2004. In contrast with previous SDA-based studies, we apply the decomposition to a global, multiregional input-output model (MRIO), which accounts for UK imports from all regions and uses region-specific production structures and CO(2) intensities. We find that improvements from "domestic" changes in efficiency and production structure led to a 148 Mt reduction in CO(2) emissions, which only partially offsets emission increases of 217 Mt from changes in the global supply chain and from growing consumer demand. Recent emission reductions achieved in the UK are not merely a reflection of a greening of the domestic supply chain, but also of a change in the international division of labor in the global production of goods and services.

  8. Water impacts of CO2 emission performance standards for fossil fuel-fired power plants.

    PubMed

    Talati, Shuchi; Zhai, Haibo; Morgan, M Granger

    2014-10-21

    We employ an integrated systems modeling tool to assess the water impacts of the new source performance standards recently proposed by the U.S. Environmental Protection Agency for limiting CO2 emissions from coal- and gas-fired power plants. The implementation of amine-based carbon capture and storage (CCS) for 40% CO2 capture to meet the current proposal will increase plant water use by roughly 30% in supercritical pulverized coal-fired power plants. The specific amount of added water use varies with power plant and CCS designs. More stringent emission standards than the current proposal would require CO2 emission reductions for natural gas combined-cycle (NGCC) plants via CCS, which would also increase plant water use. When examined over a range of possible future emission standards from 1100 to 300 lb CO2/MWh gross, new baseload NGCC plants consume roughly 60-70% less water than coal-fired plants. A series of adaptation approaches to secure low-carbon energy production and improve the electric power industry's water management in the face of future policy constraints are discussed both quantitatively and qualitatively. PMID:25229670

  9. Water impacts of CO2 emission performance standards for fossil fuel-fired power plants.

    PubMed

    Talati, Shuchi; Zhai, Haibo; Morgan, M Granger

    2014-10-21

    We employ an integrated systems modeling tool to assess the water impacts of the new source performance standards recently proposed by the U.S. Environmental Protection Agency for limiting CO2 emissions from coal- and gas-fired power plants. The implementation of amine-based carbon capture and storage (CCS) for 40% CO2 capture to meet the current proposal will increase plant water use by roughly 30% in supercritical pulverized coal-fired power plants. The specific amount of added water use varies with power plant and CCS designs. More stringent emission standards than the current proposal would require CO2 emission reductions for natural gas combined-cycle (NGCC) plants via CCS, which would also increase plant water use. When examined over a range of possible future emission standards from 1100 to 300 lb CO2/MWh gross, new baseload NGCC plants consume roughly 60-70% less water than coal-fired plants. A series of adaptation approaches to secure low-carbon energy production and improve the electric power industry's water management in the face of future policy constraints are discussed both quantitatively and qualitatively.

  10. Satellite based estimates of reduced CO and CO2 emissions due to traffic restrictions during the 2008 Beijing Olympics

    NASA Astrophysics Data System (ADS)

    Worden, H. M.; Cheng, Y.; Pfister, G.; Carmichael, G. R.; Zhang, Q.; Streets, D. G.; Deeter, M. N.; Edwards, D. P.; Gille, J. C.; Worden, J.

    2012-12-01

    We present estimates of the reductions in CO and CO2 emissions resulting from the control measures on the Beijing transportation sector taken during the 2008 Beijing Olympics. This study used MOPITT (Measurements Of Pollution In The Troposphere) multispectral satellite measurements of near surface CO along with WRF Chem (Weather Research and Forecasting model with Chemistry) simulations for Beijing during August, 2007 and 2008 to estimate changes in CO due to meteorology and emissions. Using fractional changes in the emissions inventory transportation sector along with a reported CO/CO2 emission ratio for Beijing vehicles, we find the corresponding reduction in CO2 emissions. We then compare this reduction to target CO2 emissions in the RCP (representative concentration pathway) scenarios being considered for the IPCC AR5 (Intergovernmental Panel on Climate Change, 5th Assessment Report). Our result suggests that urban traffic reductions could play a significant role in meeting target cuts for global CO2 emissions, even for the most aggressive control scenario (RCP2.6).

  11. Links between phytoplankton, CO2 emissions and water properties

    NASA Astrophysics Data System (ADS)

    Oliveira, A. P.; Cabeçadas, L.

    2009-04-01

    estimated an amount of ~5 tons of CaCO3 produced in the upper 30 m of water resulting in a emission of CO2 of 7.4 mmol m-2 d-1, which indicates that the calcification process constitutes an additional source of CO2 to the water and, eventually, to the atmosphere. Our findings illustrate the sensitivity of the phytoplankton species composition in the shelf system under study to climate variations and also its importance in the carbon cycle. Thus, if phytoplankton community is vulnerable to this type of perturbations, one may expect impacts on higher trophic levels that involve specific trophic links.Please fill in your abstract text.

  12. The TEA CO2-Lasers with High Output Emission Intensity

    NASA Astrophysics Data System (ADS)

    Panchenko, Yu. N.; Losev, V. F.; Puchikin, А. V.; Jun, Yao

    2014-03-01

    TEA CO2-lasers generating short pulse radiation and operating in a pulse-periodic mode with the repetition rate up to 10 Hz have been developed. It is shown that the addition of nitrogen up to 8% in the mixture of molecular gases СО2:H2 = 500:50 at a total pressure of P = 0.6 bar enhances the peak emission power maintaining the temporary pulse shape. An output beam intensity of 12.3 MW/cm2 was obtained for the 30 ns pulse at a laser efficiency of 2.8%. In a compact TEA СО2-laser with an active medium volume of 6 cm3, a beam with an output intensity of 24 MW/cm2 at pulse duration of 70 ns was obtained.

  13. What would dense atmospheric observation networks bring to the quantification of city CO2 emissions?

    NASA Astrophysics Data System (ADS)

    Wu, Lin; Broquet, Grégoire; Ciais, Philippe; Bellassen, Valentin; Vogel, Felix; Chevallier, Frédéric; Xueref-Remy, Irène; Wang, Yilong

    2016-06-01

    Cities currently covering only a very small portion ( < 3 %) of the world's land surface directly release to the atmosphere about 44 % of global energy-related CO2, but they are associated with 71-76 % of CO2 emissions from global final energy use. Although many cities have set voluntary climate plans, their CO2 emissions are not evaluated by the monitoring, reporting, and verification (MRV) procedures that play a key role for market- or policy-based mitigation actions. Here we analyze the potential of a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. This monitoring tool is configured for the quantification of the total and sectoral CO2 emissions in the Paris metropolitan area (˜ 12 million inhabitants and 11.4 TgC emitted in 2010) during the month of January 2011. Its performances are evaluated in terms of uncertainty reduction based on observing system simulation experiments (OSSEs). They are analyzed as a function of the number of sampling sites (measuring at 25 m a.g.l.) and as a function of the network design. The instruments presently used to measure CO2 concentrations at research stations are expensive (typically ˜ EUR 50 k per sensor), which has limited the few current pilot city networks to around 10 sites. Larger theoretical networks are studied here to assess the potential benefit of hypothetical operational lower-cost sensors. The setup of our inversion system is based on a number of diagnostics and assumptions from previous city-scale inversion experiences with real data. We find that, given our assumptions underlying the configuration of the OSSEs, with 10 stations only the uncertainty for the total city CO2 emission during 1 month is significantly reduced by the inversion by ˜ 42 %. It can be

  14. Dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO 2 emissions in Nigeria.

    PubMed

    Ali, Hamisu Sadi; Law, Siong Hook; Zannah, Talha Ibrahim

    2016-06-01

    The objective of this paper is to examine the dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO 2 emissions in Nigeria based on autoregressive distributed lags (ARDL) approach for the period of 1971-2011. The result shows that variables were cointegrated as null hypothesis was rejected at 1 % level of significance. The coefficients of long-run result reveal that urbanization does not have any significant impact on CO 2 emissions in Nigeria, economic growth, and energy consumption has a positive and significant impact on CO 2 emissions. However, trade openness has negative and significant impact on CO 2 emissions. Consumption of energy is among the main determinant of CO 2 emissions which is directly linked to the level of income. Despite the high level of urbanization in the country, consumption of energy still remains low due to lower income of the majority populace and this might be among the reasons why urbanization does not influence emissions of CO 2 in the country. Initiating more open economy policies will be welcoming in the Nigerian economy as the openness leads to the reduction of pollutants from the environment particularly CO 2 emissions which is the major gases that deteriorate physical environment. PMID:26983914

  15. Dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO 2 emissions in Nigeria.

    PubMed

    Ali, Hamisu Sadi; Law, Siong Hook; Zannah, Talha Ibrahim

    2016-06-01

    The objective of this paper is to examine the dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO 2 emissions in Nigeria based on autoregressive distributed lags (ARDL) approach for the period of 1971-2011. The result shows that variables were cointegrated as null hypothesis was rejected at 1 % level of significance. The coefficients of long-run result reveal that urbanization does not have any significant impact on CO 2 emissions in Nigeria, economic growth, and energy consumption has a positive and significant impact on CO 2 emissions. However, trade openness has negative and significant impact on CO 2 emissions. Consumption of energy is among the main determinant of CO 2 emissions which is directly linked to the level of income. Despite the high level of urbanization in the country, consumption of energy still remains low due to lower income of the majority populace and this might be among the reasons why urbanization does not influence emissions of CO 2 in the country. Initiating more open economy policies will be welcoming in the Nigerian economy as the openness leads to the reduction of pollutants from the environment particularly CO 2 emissions which is the major gases that deteriorate physical environment.

  16. 40 CFR Table U-1 to Subpart U of... - CO2 Emission Factors for Common Carbonates

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CO2 Emission Factors for Common.... 98, Subpt. U, Table U-1 Table U-1 to Subpart U of Part 98—CO2 Emission Factors for Common Carbonates Mineral name—carbonate CO2 emission factor(tons CO2/ton carbonate) Limestone—CaCO3 0.43971...

  17. 40 CFR Table U-1 to Subpart U of... - CO2 Emission Factors for Common Carbonates

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false CO2 Emission Factors for Common.... 98, Subpt. U, Table U-1 Table U-1 to Subpart U of Part 98—CO2 Emission Factors for Common Carbonates Mineral name—carbonate CO2 emission factor(tons CO2/ton carbonate) Limestone—CaCO3 0.43971...

  18. 40 CFR Table U-1 to Subpart U of... - CO2 Emission Factors for Common Carbonates

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false CO2 Emission Factors for Common.... 98, Subpt. U, Table U-1 Table U-1 to Subpart U of Part 98—CO2 Emission Factors for Common Carbonates Mineral name—carbonate CO2 emission factor(tons CO2/ton carbonate) Limestone—CaCO3 0.43971...

  19. 40 CFR Table U-1 to Subpart U of... - CO2 Emission Factors for Common Carbonates

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CO2 Emission Factors for Common.... 98, Subpt. U, Table U-1 Table U-1 to Subpart U of Part 98—CO2 Emission Factors for Common Carbonates Mineral name—carbonate CO2 emission factor(tons CO2/ton carbonate) Limestone—CaCO3 0.43971...

  20. Wavelet-based reconstruction of fossil-fuel CO2 emissions from sparse measurements

    NASA Astrophysics Data System (ADS)

    McKenna, S. A.; Ray, J.; Yadav, V.; Van Bloemen Waanders, B.; Michalak, A. M.

    2012-12-01

    We present a method to estimate spatially resolved fossil-fuel CO2 (ffCO2) emissions from sparse measurements of time-varying CO2 concentrations. It is based on the wavelet-modeling of the strongly non-stationary spatial distribution of ffCO2 emissions. The dimensionality of the wavelet model is first reduced using images of nightlights, which identify regions of human habitation. Since wavelets are a multiresolution basis set, most of the reduction is accomplished by removing fine-scale wavelets, in the regions with low nightlight radiances. The (reduced) wavelet model of emissions is propagated through an atmospheric transport model (WRF) to predict CO2 concentrations at a handful of measurement sites. The estimation of the wavelet model of emissions i.e., inferring the wavelet weights, is performed by fitting to observations at the measurement sites. This is done using Staggered Orthogonal Matching Pursuit (StOMP), which first identifies (and sets to zero) the wavelet coefficients that cannot be estimated from the observations, before estimating the remaining coefficients. This model sparsification and fitting is performed simultaneously, allowing us to explore multiple wavelet-models of differing complexity. This technique is borrowed from the field of compressive sensing, and is generally used in image and video processing. We test this approach using synthetic observations generated from emissions from the Vulcan database. 35 sensor sites are chosen over the USA. FfCO2 emissions, averaged over 8-day periods, are estimated, at a 1 degree spatial resolutions. We find that only about 40% of the wavelets in emission model can be estimated from the data; however the mix of coefficients that are estimated changes with time. Total US emission can be reconstructed with about ~5% errors. The inferred emissions, if aggregated monthly, have a correlation of 0.9 with Vulcan fluxes. We find that the estimated emissions in the Northeast US are the most accurate. Sandia

  1. Cost Effective Measures to Reduce CO2 Emissions in the Air Freight Sector

    NASA Technical Reports Server (NTRS)

    Blinge, Magnus

    2003-01-01

    This paper presents cost effective measures to reduce CO2 emissions in the air freight sector. One door-to-door transport chain is studied in detail from a Scandinavian city to a city in southern Europe. The transport chain was selected by a group of representatives from the air freight sector in order to encompass general characteristics within the sector. Three different ways of shipping air cargo are studied, i.e., by air freighter, as belly freight (in passenger aircrafts) and trucking. CO2 emissions are calculated for each part of the transport chain and its relative importance towards the total amount CO2 emitted during the whole transport chain is shown. It is confirmed that the most CO2 emitting part of the transport chain is the actual flight and that it is in the take-off and climbing phases that most fuel are burned. It is also known that the technical development of aircraft implies a reduction in fuel consumption for each new generation of aircraft. Thus, the aircraft manufacturers have an important role in this development. Having confirmed these observations, this paper focuses on other factors that significantly affects the fuel consumption. Analyzed factors are, e.g., optimization of speed and altitude, traffic management, congestion on and around the airfields, tankering, "latest acceptance time" for goods and improving the load factor. The different factors relative contribution to the total emission levels for the transport chain has been estimated.

  2. Quantification of fossil fuel CO2 emissions at the urban scale: Results from the Indianapolis Flux Project (INFLUX)

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Cambaliza, M. L.; Sweeney, C.; Karion, A.; Newberger, T.; Tans, P. P.; Lehman, S.; Davis, K. J.; Miles, N. L.; Richardson, S.; Lauvaux, T.; Shepson, P.; Gurney, K. R.; Song, Y.; Razlivanov, I. N.

    2012-12-01

    Emissions of fossil fuel CO2 (CO2ff) from anthropogenic sources are the primary driver of observed increases in the atmospheric CO2 burden, and hence global warming. Quantification of the magnitude of fossil fuel CO2 emissions is vital to improving our understanding of the global and regional carbon cycle, and independent evaluation of reported emissions is essential to the success of any emission reduction efforts. The urban scale is of particular interest, because ~75% CO2ff is emitted from urban regions, and cities are leading the way in attempts to reduce emissions. Measurements of 14CO2 can be used to determine CO2ff, yet existing 14C measurement techniques require laborious laboratory analysis and measurements are often insufficient for inferring an urban emission flux. This presentation will focus on how 14CO2 measurements can be combined with those of more easily measured ancillary tracers to obtain high resolution CO2ff mixing ratio estimates and then infer the emission flux. A pilot study over Sacramento, California showed strong correlations between CO2ff and carbon monoxide (CO) and demonstrated an ability to quantify the urban flux, albeit with large uncertainties. The Indianapolis Flux Project (INFLUX) aims to develop and assess methods to quantify urban greenhouse gas emissions. Indianapolis was chosen as an ideal test case because it has relatively straightforward meteorology; a contained, isolated, urban region; and substantial and well-known fossil fuel CO2 emissions. INFLUX incorporates atmospheric measurements of a suite of gases and isotopes including 14C from light aircraft and from a network of existing tall towers surrounding the Indianapolis urban area. The recently added CO2ff content is calculated from measurements of 14C in CO2, and then convolved with atmospheric transport models and ancillary data to estimate the urban CO2ff emission flux. Significant innovations in sample collection include: collection of hourly averaged samples to

  3. Performance analysis of CO(2) emissions and energy efficiency of metal industries in China.

    PubMed

    Shao, Chaofeng; Guan, Yang; Wan, Zheng; Chu, Chunli; Ju, Meiting

    2014-02-15

    Nonferrous metal industries play an important role in China's national economy and are some of the country's largest energy consumers. To better understand the nature of CO(2) emissions from these industries and to further move towards low-carbon development in this industry sector, this study investigates the CO(2) emissions of 12 nonferrous metal industries from 2003 to 2010 based on their life-cycle assessments. It then classifies these industries into four "emission-efficiency" types through cluster analysis. The results show that (1) the industrial economy and energy consumption of China's nonferrous metal industries have grown rapidly, although their recent energy consumption rate shows a declining trend. (2) The copper, aluminum, zinc, lead, and magnesium industries, classified as high-emission industries, are the main contributors of CO(2) emissions. The results have implications for policy decisions that aim to enhance energy efficiency, particularly for promoting the transformation of low-efficiency industries to high-efficiency ones. The study also highlights the important role of policy development in technological innovations, optimization, and upgrades, the reduction of coal proportion in energy consumption, and the advancement of new energy sources.

  4. A robust and efficient cobalt molecular catalyst for CO2 reduction.

    PubMed

    Chan, Sharon Lai-Fung; Lam, Tsz Lung; Yang, Chen; Yan, Siu-Cheong; Cheng, Nga Man

    2015-05-01

    Visible-light driven CO2 reduction is considered to be a sustainable energy source. However, earth-abundant molecular catalysts with high efficiency and robustness towards solar-driven CO2 reduction are limited. Herein, we report a cobalt complex supported by a tetradentate tripodal ligand, which demonstrates catalytic solar-driven CO2 reduction with TON(CO) > 900 over 70 h in the presence of a photosensitizer. PMID:25783610

  5. Elevated [CO2] magnifies isoprene emissions under heat and improves thermal resistance in hybrid aspen

    PubMed Central

    Niinemets, Ülo

    2013-01-01

    Isoprene emissions importantly protect plants from heat stress, but the emissions become inhibited by instantaneous increase of [CO2], and it is currently unclear how isoprene-emitting plants cope with future more frequent and severe heat episodes under high [CO2]. Hybrid aspen (Populus tremula x Populus tremuloides) saplings grown under ambient [CO2] of 380 μmol mol−1 and elevated [CO2] of 780 μmol mol−1 were used to test the hypothesis that acclimation to elevated [CO2] reduces the inhibitory effect of high [CO2] on emissions. Elevated-[CO2]-grown plants had greater isoprene emission capacity and a stronger increase of isoprene emissions with increasing temperature. High temperatures abolished the instantaneous [CO2] sensitivity of isoprene emission, possibly due to removing the substrate limitation resulting from curbed cycling of inorganic phosphate. As a result, isoprene emissions were highest in elevated-[CO2]-grown plants under high measurement [CO2]. Overall, elevated growth [CO2] improved heat resistance of photosynthesis, in particular, when assessed under high ambient [CO2] and the improved heat resistance was associated with greater cellular sugar and isoprene concentrations. Thus, contrary to expectations, these results suggest that isoprene emissions might increase in the future. PMID:24153419

  6. Energy use and CO2 emissions of China’s industrial sector from a global perspective

    SciTech Connect

    Zhou, Sheng; Kyle, G. Page; Yu, Sha; Clarke, Leon E.; Eom, Jiyong; Luckow, Patrick W.; Chaturvedi, Vaibhav; Zhang, Xiliang; Edmonds, James A.

    2013-07-10

    The industrial sector has accounted for more than 50% of China’s final energy consumption in the past 30 years. Understanding the future emissions and emissions mitigation opportunities depends on proper characterization of the present-day industrial energy use, as well as industrial demand drivers and technological opportunities in the future. Traditionally, however, integrated assessment research has handled the industrial sector of China in a highly aggregate form. In this study, we develop a technologically detailed, service-oriented representation of 11 industrial subsectors in China, and analyze a suite of scenarios of future industrial demand growth. We find that, due to anticipated saturation of China’s per-capita demands of basic industrial goods, industrial energy demand and CO2 emissions approach a plateau between 2030 and 2040, then decrease gradually. Still, without emissions mitigation policies, the industrial sector remains heavily reliant on coal, and therefore emissions-intensive. With carbon prices, we observe some degree of industrial sector electrification, deployment of CCS at large industrial point sources of CO2 emissions at low carbon prices, an increase in the share of CHP systems at industrial facilities. These technological responses amount to reductions of industrial emissions (including indirect emission from electricity) are of 24% in 2050 and 66% in 2095.

  7. Achieving CO2 reductions in Colombia: Effects of carbon taxes and abatement targets

    DOE PAGES

    Calderón, Silvia; Alvarez, Andres Camilo; Loboguerrero, Ana Maria; Arango, Santiago; Calvin, Katherine; Kober, Tom; Daenzer, Kathryn; Fisher-Vanden, Karen

    2015-06-03

    In this paper we investigate CO2 emission scenarios for Colombia and the effects of implementing carbon taxes and abatement targets on the energy system. By comparing baseline and policy scenario results from two integrated assessment partial equilibrium models TIAM-ECN and GCAM and two general equilibrium models Phoenix and MEG4C, we provide an indication of future developments and dynamics in the Colombian energy system. Currently, the carbon intensity of the energy system in Colombia is low compared to other countries in Latin America. However, this trend may change given the projected rapid growth of the economy and the potential increase inmore » the use of carbon-based technologies. Climate policy in Colombia is under development and has yet to consider economic instruments such as taxes and abatement targets. This paper shows how taxes or abatement targets can achieve significant CO2 reductions in Colombia. Though abatement may be achieved through different pathways, taxes and targets promote the entry of cleaner energy sources into the market and reduce final energy demand through energy efficiency improvements and other demand-side responses. The electric power sector plays an important role in achieving CO2 emission reductions in Colombia, through the increase of hydropower, the introduction of wind technologies, and the deployment of biomass, coal and natural gas with CO2 capture and storage (CCS). Uncertainty over the prevailing mitigation pathway reinforces the importance of climate policy to guide sectors toward low-carbon technologies. This paper also assesses the economy-wide implications of mitigation policies such as potential losses in GDP and consumption. As a result, an assessment of the legal, institutional, social and environmental barriers to economy-wide mitigation policies is critical yet beyond the scope of this paper.« less

  8. Mapping of the CO2 and anthropogenic heat emission under spatially explicit urban land use scenarios

    NASA Astrophysics Data System (ADS)

    Nakamichi, K.; Yamagata, Y.; Seya, H.

    2010-12-01

    The serious further efforts on CO2 and other green house gases emission reduction by global climate change mitigation remain as an urgent global issue to be solved. From the viewpoint of urban land use measures, the realization of low-carbon city is the key to change people’s behavior to reduce CO2 emission. In this respect, a lot of studies aimed at realizing low-carbon city are progressing on a number of fronts, including city planning and transportation planning. With respect to the low-carbon city, compact city is expected to reduce CO2 emission from transportation sector. Hence many studies have been conducted with scenario analysis considering modal share change, for instance, increase of public transportation use and reduction of trip length by car. On the other hand, it is important that CO2 emission from not only transportation sector but also residential sector can be reduced by a move from a detached house to a condominium, the change of family composition types and so on. In regard to residential sector, it has been founded that CO2 emission units differ among family composition types, for example, the single-person household emit more CO2 in general. From the viewpoint of an urban climate prediction, the possible range of future land use change should be recognized as the input parameters for the climate models. In addition to CO2 emission, the anthropogenic heat emission is also important as an input data of climate models in order to evaluate the social and economic impacts of urban land use change. The objective of this study is to demonstrate a compact city scenario and a dispersion scenario in Tokyo metropolitan area, which is the largest metropolitan area in the world, and to examine future climate change mitigation policies including land use for realization of low-carbon city. We have created two scenarios of population distribution by using an urban economic model. In these scenarios we have assumed extreme cases in order to show the

  9. 40 CFR 1037.105 - Exhaust emission standards for CO2 for vocational vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.105 Exhaust emission standards for CO2 for vocational vehicles. (a... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Exhaust emission standards for CO2...

  10. 40 CFR 1037.105 - Exhaust emission standards for CO2 for vocational vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.105 Exhaust emission standards for CO2 for vocational vehicles. (a... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Exhaust emission standards for CO2...

  11. 40 CFR 1037.105 - Exhaust emission standards for CO2 for vocational vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.105 Exhaust emission standards for CO2 for vocational vehicles. (a... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Exhaust emission standards for CO2...

  12. Reducing U.S. residential energy use and CO2 emissions: how much, how soon, and at what cost?

    PubMed

    Lima Azevedo, Inês; Morgan, M Granger; Palmer, Karen; Lave, Lester B

    2013-03-19

    There is growing interest in reducing energy use and emissions of carbon dioxide from the residential sector by deploying cost-effectiveness energy efficiency measures. However, there is still large uncertainty about the magnitude of the reductions that could be achieved by pursuing different energy efficiency measures across the nation. Using detailed estimates of the current inventory and performance of major appliances in U.S. homes, we model the cost, energy, and CO2 emissions reduction if they were replaced with alternatives that consume less energy or emit less CO2. We explore trade-offs between reducing CO2, reducing primary or final energy, or electricity consumption. We explore switching between electricity and direct fuel use, and among fuels. The trade-offs between different energy efficiency policy goals, as well as the environmental metrics used, are important but have been largely unexplored by previous energy modelers and policy-makers. We find that overnight replacement of the full stock of major residential appliances sets an upper bound of just over 710 × 10(6) tonnes/year of CO2 or a 56% reduction from baseline residential emissions. However, a policy designed instead to minimize primary energy consumption instead of CO2 emissions will achieve a 48% reduction in annual carbon dioxide emissions from the nine largest energy consuming residential end-uses. Thus, we explore the uncertainty regarding the main assumptions and different policy goals in a detailed sensitivity analysis. PMID:23398047

  13. Thermodynamics and kinetics of CO2, CO, and H+ binding to the metal centre of CO2 reduction catalysts.

    PubMed

    Schneider, Jacob; Jia, Hongfei; Muckerman, James T; Fujita, Etsuko

    2012-03-21

    In our developing world, carbon dioxide has become one of the most abundant greenhouse gases in the atmosphere. It is a stable, inert, small molecule that continues to present significant challenges toward its chemical activation as a useful carbon end product. This tutorial review describes one approach to the reduction of carbon dioxide to carbon fuels, using cobalt and nickel molecular catalysts, with particular focus on studying the thermodynamics and kinetics of CO(2) binding to metal catalytic sites.

  14. Atmospheric observations of carbon monoxide and fossil fuel CO2 emissions from East Asia

    NASA Astrophysics Data System (ADS)

    Turnbull, Jocelyn C.; Tans, Pieter P.; Lehman, Scott J.; Baker, David; Conway, Thomas J.; Chung, Y. S.; Gregg, Jay; Miller, John B.; Southon, John R.; Zhou, Ling-Xi

    2011-12-01

    Flask samples from two sites in East Asia, Tae-Ahn Peninsula, Korea (TAP), and Shangdianzi, China (SDZ), were measured for trace gases including CO2, CO and fossil fuel CO2 (CO2ff, derived from Δ14CO2observations). The five-year TAP record shows high CO2ff when local air comes from the Korean Peninsula. Most samples, however, reflect air masses from Northeastern China with lower CO2ff. Our small set of SDZ samples from winter 2009/2010 have strongly elevated CO2ff. Biospheric CO2 contributes substantially to total CO2variability at both sites, even in winter when non-fossil CO2 sources (including photosynthesis, respiration, biomass burning and biofuel use) contribute 20-30% of the total CO2 enhancement. Carbon monoxide (CO) correlates strongly with CO2ff. The SDZ and TAP far-field (China influenced) samples have CO: CO2ff ratios (RCO:CO2ff) of 47 ± 2 and 44 ± 3 ppb/ppm respectively, consistent with recent bottom-up inventory estimates and other observational studies. Locally influenced TAP samples fall into two distinct data sets, ascribed to air sourced from South Korea and North Korea. The South Korea samples have low RCO:CO2ffof 13 ± 3 ppb/ppm, slightly higher than bottom-up inventories, but consistent with emission ratios for other developed nations. We compare our CO2ff observations with modeled CO2ff using the FLEXPART Lagrangian particle dispersion model convolved with a bottom-up CO2ff emission inventories. The modeled annual mean CO2ff mole fractions are consistent with our observations when the model inventory includes the reported 63% increase in Chinese emissions from 2004 to 2010, whereas a model version which holds Chinese emissions flat is unable to replicate the observations.

  15. Development of a preprototype Sabatier CO2 reduction subsystem

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Birbara, P.

    1981-01-01

    A lightweight, quick starting reactor utilizes a highly active and physically durable methanation catalyst composed of ruthenium on alumina. The use of this improved catalyst permits a single straight through plug flow design with an average lean component H2/CO2 conversion efficiency of over 99% over a range of H2/CO2 molar ratios of 1.8 to 5 while operating with flows equivalent to a crew size of one person steadystate to 3 persons cyclical. The reactor requires no heater operation after start-up even during simulated 55 minute lightside/39 minute darkside orbital operation over the above range of molar ratios and crew loadings. Subsystem performance was proven by parametric testing and endurance testing over a wide range of crew sizes and metabolic loadings. The subsystem's operation and performance is controlled by a microprocessor and displayed on a nineteen inch multi-colored cathode ray tube.

  16. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen

    PubMed Central

    Niinemets, Ülo; Sun, Zhihong

    2015-01-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol–1 or elevated [CO2] of 780 μmol mol–1. The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size. PMID:25399006

  17. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.

    PubMed

    Niinemets, Ülo; Sun, Zhihong

    2015-02-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol(-1) or elevated [CO2] of 780 μmol mol(-1). The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size.

  18. GLOBAL ANTROPOGENIC NON-CO2 GREENHOUSE GAS EMISSIONS: 1990-2020

    EPA Science Inventory

    This report will synthesize available data on emissions of non-CO2 greenhouse gases by gas, source category, and country or region. Historic emissions data, as well as projected emission levels will be provided.

  19. Photocatalytic Reduction of CO2 over Heterostructure Semiconductors into Value-Added Chemicals.

    PubMed

    Guo, Ling-Ju; Wang, Yan-Jie; He, Tao

    2016-08-01

    Photoreduction of CO2 , which utilizes solar energy to convert CO2 into hydrocarbons, can be an effective means to overcome the increasing energy crisis and mitigate the rising emissions of greenhouse gas. This article covers recent advances in the CO2 photoreduction over heterostructure-based photocatalysts. The fundamentals of CO2 photoreduction and classification of the heterostructured photocatalysts are discussed first, followed by the latest work on the CO2 photoreduction over heterostructured photocatalysts in terms of the classification of the coupling semiconductors. Finally, a brief summary and a perspective on the challenges in this area are presented. PMID:27276171

  20. The effect of natural gas supply on US renewable energy and CO2 emissions

    NASA Astrophysics Data System (ADS)

    Shearer, Christine; Bistline, John; Inman, Mason; Davis, Steven J.

    2014-09-01

    Increased use of natural gas has been promoted as a means of decarbonizing the US power sector, because of superior generator efficiency and lower CO2 emissions per unit of electricity than coal. We model the effect of different gas supplies on the US power sector and greenhouse gas (GHG) emissions. Across a range of climate policies, we find that abundant natural gas decreases use of both coal and renewable energy technologies in the future. Without a climate policy, overall electricity use also increases as the gas supply increases. With reduced deployment of lower-carbon renewable energies and increased electricity consumption, the effect of higher gas supplies on GHG emissions is small: cumulative emissions 2013-55 in our high gas supply scenario are 2% less than in our low gas supply scenario, when there are no new climate policies and a methane leakage rate of 1.5% is assumed. Assuming leakage rates of 0 or 3% does not substantially alter this finding. In our results, only climate policies bring about a significant reduction in future CO2 emissions within the US electricity sector. Our results suggest that without strong limits on GHG emissions or policies that explicitly encourage renewable electricity, abundant natural gas may actually slow the process of decarbonization, primarily by delaying deployment of renewable energy technologies.

  1. Satellite-based estimates of reduced CO and CO2 emissions due to traffic restrictions during the 2008 Beijing Olympics

    NASA Astrophysics Data System (ADS)

    Worden, Helen M.; Cheng, Yafang; Pfister, Gabriele; Carmichael, Gregory R.; Zhang, Qiang; Streets, David G.; Deeter, Merritt; Edwards, David P.; Gille, John C.; Worden, John R.

    2012-07-01

    During the 2008 Olympics, the Chinese government made a significant effort to improve air quality in Beijing, including restrictions on traffic. Here we estimate the reductions in carbon monoxide (CO) and carbon dioxide (CO2) emissions resulting from the control measures on Beijing transportation. Using MOPITT (Measurements Of Pollution In The Troposphere) multispectral satellite observations of near-surface CO along with WRF-Chem (Weather Research and Forecasting model with Chemistry) simulations for Beijing during August, 2007 and 2008, we estimate changes in CO due to meteorology and transportation sector emissions. Applying a reported CO/CO2 emission ratio for fossil fuels, we find the corresponding reduction in CO2, 60 ± 36 Gg[CO2]/day. As compared to emission scenarios being considered for the IPCC AR5 (Intergovernmental Panel on Climate Change, 5th Assessment Report), this result suggests that urban traffic controls on the Beijing Olympics scale could play a significant role in meeting target reductions for global CO2 emissions.

  2. Peak CO2? China's Emissions Trajectories to 2050

    SciTech Connect

    Zhou, Nan; Fridley, David G.; McNeil, Michael; Zheng, Nina; Ke, Jing; Levine, Mark

    2011-05-01

    As a result of soaring energy demand from a staggering pace of economic growth and the related growth of energy-intensive industry, China overtook the United States to become the world's largest contributor to CO{sub 2} emissions in 2007. At the same time, China has taken serious actions to reduce its energy and carbon intensity by setting both short-term energy intensity reduction goal for 2006 to 2010 as well as long-term carbon intensity reduction goal for 2020. This study focuses on a China Energy Outlook through 2050 that assesses the role of energy efficiency policies in transitioning China to a lower emission trajectory and meeting its intensity reduction goals. In the past years, LBNL has established and significantly enhanced the China End-Use Energy Model based on the diffusion of end-use technologies and other physical drivers of energy demand. This model presents an important new approach for helping understand China's complex and dynamic drivers of energy consumption and implications of energy efficiency policies through scenario analysis. A baseline ('Continued Improvement Scenario') and an alternative energy efficiency scenario ('Accelerated Improvement Scenario') have been developed to assess the impact of actions already taken by the Chinese government as well as planned and potential actions, and to evaluate the potential for China to control energy demand growth and mitigate emissions. It is a common belief that China's CO{sub 2} emissions will continue to grow throughout this century and will dominate global emissions. The findings from this research suggest that this will not likely be the case because of saturation effects in appliances, residential and commercial floor area, roadways, railways, fertilizer use, and urbanization will peak around 2030 with slowing population growth. The baseline and alternative scenarios also demonstrate that the 2020 goals can be met and underscore the significant role that policy-driven energy efficiency

  3. FUEL ECONOMY AND CO2 EMISSIONS STANDARDS, MANUFACTURER PRICING STRATEGIES, AND FEEBATES

    SciTech Connect

    Liu, Changzheng; Greene, David L; Bunch, Dr David S.

    2012-01-01

    Corporate Average Fuel Economy (CAFE) standards and CO2 emissions standards for 2012 to 2016 have significantly increased the stringency of requirements for new light-duty vehicle fuel efficiency. This study investigates the role of technology adoption and pricing strategies in meeting new standards, as well as the impact of feebate policies. The analysis is carried out by means of a dynamic optimization model that simulates manufacturer decisions with the objective of maximizing social surplus while simultaneously considering consumer response and meeting CAFE and emissions standards. The results indicate that technology adoption plays the major role and that the provision of compliance flexibility and the availability of cost-effective advanced technologies help manufacturers reduce the need for pricing to induce changes in the mix of vehicles sold. Feebates, when implemented along with fuel economy and emissions standards, can bring additional fuel economy improvement and emissions reduction, but the benefit diminishes with the increasing stringency of the standards.

  4. Graphene-Based Photocatalysts for CO2 Reduction to Solar Fuel.

    PubMed

    Low, Jingxiang; Yu, Jiaguo; Ho, Wingkei

    2015-11-01

    Recently, photocatalytic CO2 reduction for solar fuel production has attracted much attention because of its potential for simultaneously solving energy and global warming problems. Many studies have been conducted to prepare novel and efficient photocatalysts for CO2 reduction. Graphene, a two-dimensional material, has been increasingly used in photocatalytic CO2 reduction. In theory, graphene shows several remarkable properties, including excellent electronic conductivity, good optical transmittance, large specific surface area, and superior chemical stability. Attributing to these advantages, fabrication of graphene-based materials has been known as one of the most feasible strategies to improve the CO2 reduction performance of photocatalysts. This Perspective mainly focuses on the recent important advances in the fabrication and application of graphene-based photocatalysts for CO2 reduction to solar fuels. The existing challenges and difficulties of graphene-based photocatalysts are also discussed for future application.

  5. Abiotic CO2 reduction during geologic carbon sequestration facilitated by Fe(II)-bearing minerals

    NASA Astrophysics Data System (ADS)

    Nielsen, L. C.; Maher, K.; Bird, D. K.; Brown, G. E.; Thomas, B.; Johnson, N. C.; Rosenbauer, R. J.

    2012-12-01

    Redox reactions involving subsurface minerals and fluids and can lead to the abiotic generation of hydrocarbons from CO2 under certain conditions. Depleted oil reservoirs and saline aquifers targeted for geologic carbon sequestration (GCS) can contain significant quantities of minerals such as ferrous chlorite, which could facilitate the abiotic reduction of carbon dioxide to n-carboxylic acids, hydrocarbons, and amorphous carbon (C0). If such reactions occur, the injection of supercritical CO2 (scCO2) could significantly alter the oxidation state of the reservoir and cause extensive reorganization of the stable mineral assemblage via dissolution and reprecipitation reactions. Naturally occurring iron oxide minerals such as magnetite are known to catalyze CO2 reduction, resulting in the synthesis of organic compounds. Magnetite is thermodynamically stable in Fe(II) chlorite-bearing mineral assemblages typical of some reservoir formations. Thermodynamic calculations demonstrate that GCS reservoirs buffered by the chlorite-kaolinite-carbonate(siderite/magnesite)-quartz assemblage favor the reduction of CO2 to n-carboxylic acids, hydrocarbons, and C0, although the extent of abiotic CO2 reduction may be kinetically limited. To investigate the rates of abiotic CO2 reduction in the presence of magnetite, we performed batch abiotic CO2 reduction experiments using a Dickson-type rocking hydrothermal apparatus at temperatures (373 K) and pressures (100 bar) within the range of conditions relevant to GCS. Blank experiments containing CO2 and H2 were used to rule out the possibility of catalytic activity of the experimental apparatus. Reaction of brine-suspended magnetite nanoparticles with scCO2 at H2 partial pressures typical of reservoir rocks - up to 100 and 0.1 bars respectively - was used to investigate the kinetics of magnetite-catalyzed abiotic CO2 reduction. Later experiments introducing ferrous chlorite (ripidolite) were carried out to determine the potential for

  6. Toward Solar-Driven Photocatalytic CO2 Reduction Using Water as an Electron Donor.

    PubMed

    Sato, Shunsuke; Arai, Takeo; Morikawa, Takeshi

    2015-06-01

    Developing a system for the production of organic chemicals via CO2 reduction is an important area of research that has the potential to address global warming and fossil fuel consumption. In addition, CO2 reduction promotes carbon source recycling. Solar energy is the largest exploitable resource among renewable energy resources, providing more energy to Earth per hour than the total energy consumed by humans in 1 year. This report describes the advantages and disadvantages of the available CO2 reduction and H2O oxidation photocatalysts and the conjugation of photocatalytic CO2 reduction with H2O oxidation for the creation of an artificial photosynthesis system. In this system, CO2 photoreduction and H2O photooxidation proceeded simultaneously within one system under sunlight irradiation using a hybrid of semiconductors and molecular metal-complex catalysts.

  7. Does winter warming enhance cold CO2 emission from temperate continental soils?

    NASA Astrophysics Data System (ADS)

    Kurganova, Irina; Lopes de Gerenyu, Valentin; Khoroshaev, Dmitry

    2016-04-01

    revealed during the early spring FTC. They corresponded to a rapid thawing of frozen soils due to the customary rise of air temperature at the beginning of March. These CO2 emission pulses during early spring contributed between 43% and 70% to the total cold CO2 fluxes from frozen soils ('Ref" and "NoSn" variants). The contribution of spring fluxes from unfrozen soils ("NoFr" treatment) to the total cold CO2 emission was about 25%. Our findings produce evidence that winter warming in temperate continental regions has resulted in a reduction in the permanent snow pack, an increase in the frequency of freezing-thawing events and can be followed by a prolongation of the period when soils remain frozen. Soil respiration fluxes were greatly reduced owing to an increase in frost stress both for plants and for the soil microbial community. Therefore, winter warming in temperate continental areas decreases cold CO2 emissions from soils into the atmosphere and is expected thereby to lead to a rise in the annual carbon sink in ecosystems. This study was supported by the Russian Science Foundation (14-14-00625) and the Russian Foundation for Basic Research (project 15-04-05156a).

  8. Emission of CO2 from seafioor hydrothermal systems at Mariana Trough

    NASA Astrophysics Data System (ADS)

    Maeda, Y.; Shitashima, K.

    2007-12-01

    Hydrothermal vent fluids are highly enriched in CO2 and the CO2 rich fluids are released into the ocean as a hydrothermal plume. Especially, the emission of hydrothermal-related liquid CO2 from the seafloor (about 1500m) was discovered at the Okinawa Trough and Mariana Trough. At these areas, it is considered that the liquid CO2 rises up to shallow depth as a CO2 droplet and that the rising CO2 droplet dissolves gradually in ambient seawater. The observation of the hydrothermal-related CO2 would provide the opportunity for understanding the physic-chemical behavior and diffusion process of liquid CO2 in the ocean. Newly developed in-situ pH/pCO2 sensor can detect precisely and rapidly the changes of pH and pCO2 derived from high CO2 concentration. At southern Mariana Trough, the pH/pCO2 sensor was installed onto the manned submersible and in-situ pH and pCO2 data were measured every 10 seconds during the operation on the hydrothermal active site. Mapping survey of low pH and pCO2 distribution was performed on the hydrothermal active site by the grid navigation of the manned submersible that installed the pH/pCO2 sensor. The results of pH mapping survey showed only localized pH depression at the hydrothermal active site. At NW Eifuku submarine volcano, hydrothermal-related liquid CO2 dispersion was observed by using a towing multi-layer monitoring system. This system can observe the dispersion behavior of CO2 by towing several in-situ pH/pCO2 sensors and SSBL transponders in the high CO2 plume. Low pH plume of 100m high and 200m wide was detected above the summit of NW Eifuku submarine volcano.

  9. Temporal variability of air-sea CO2 exchange in a low-emission estuary

    NASA Astrophysics Data System (ADS)

    Mørk, Eva Thorborg; Sejr, Mikael Kristian; Stæhr, Peter Anton; Sørensen, Lise Lotte

    2016-07-01

    There is the need for further study of whether global estimates of air-sea CO2 exchange in estuarine systems capture the relevant temporal variability and, as such, the temporal variability of bulk parameterized and directly measured CO2 fluxes was investigated in the Danish estuary, Roskilde Fjord. The air-sea CO2 fluxes showed large temporal variability across seasons and between days and that more than 30% of the net CO2 emission in 2013 was a result of two large fall and winter storms. The diurnal variability of ΔpCO2 was up to 400 during summer changing the estuary from a source to a sink of CO2 within the day. Across seasons the system was suggested to change from a sink of atmospheric CO2 during spring to near neutral during summer and later to a source of atmospheric CO2 during fall. Results indicated that Roskilde Fjord was an annual low-emission estuary, with an estimated bulk parameterized release of 3.9 ± 8.7 mol CO2 m-2 y-1 during 2012-2013. It was suggested that the production-respiration balance leading to the low annual emission in Roskilde Fjord, was caused by the shallow depth, long residence time and high water quality in the estuary. In the data analysis the eddy covariance CO2 flux samples were filtered according to the H2Osbnd CO2 cross-sensitivity assessment suggested by Landwehr et al. (2014). This filtering reduced episodes of contradicting directions between measured and bulk parameterized air-sea CO2 exchanges and changed the net air-sea CO2 exchange from an uptake to a release. The CO2 gas transfer velocity was calculated from directly measured CO2 fluxes and ΔpCO2 and agreed to previous observations and parameterizations.

  10. Non-thermal 10 micrometers CO2 emission lines in the atmospheres of Mars and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, M. A.

    1975-01-01

    Mechanisms for the excitation of strong 10 micrometer CO2 emission lines seen on Mars and Venus are examined. Line absorption of near IR solar flux directly by CO2 or by H2O with collisional transfer of energy to CO2 are proposed as likely excitation mechanisms. Altitudes for peak 10 micrometer emission are estimated to be near 80 km for Mars and 120 km for Venus.

  11. Nonthermal 10 micron CO2 emission lines in the atmospheres of Mars and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, M. A.; Betz, A. L.; Mclaren, R. A.; Townes, C. H.; Sutton, E. C.

    1976-01-01

    Mechanisms are examined for excitation of strong 10-micron CO2 emission lines seen on Mars and Venus. Line absorption of near-infrared solar flux directly by CO2 or H2O with collisional transfer of energy to CO2 are proposed as likely excitation mechanisms. Altitudes for peak 10-micron emission are estimated to be near 80 km for Mars and 120 km for Venus.

  12. Elevated CO2 and O3 modify N turnover rates, but not N2O emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to predict and mitigate future climate change, it is essential to understand effects of elevated CO2 (eCO2) and O3 (eO3) on N-cycling, including N2O emissions, due to plant mediated changes. This is of particular interest for agroecosystems, since N-cycling and N2O emissions are responsive ...

  13. Isoprene leaf emission under CO2 free atmosphere: why and how?

    NASA Astrophysics Data System (ADS)

    Garcia, S.

    2015-12-01

    Isoprene (C5H8) is a reactive hydrocarbon gas emitted at high rates by tropical vegetation, which affects atmospheric chemistry and climate and, in the leaf level, is a very important agent against environmental stress. Under optimal conditions for photosynthesis, the majority of carbon used for isoprene biosynthesis is a direct product from recently assimilated atmospheric CO2. However, the contribution of 'alternate' carbon sources, that increase with leaf temperature, have been demonstrated and emissions of isoprene from 'alternate' carbon sources under ambient CO2 below the compensation point for photosynthesis have been observed. In this study, we investigated the response of leaf isoprene emissions under 450 ppm CO2 and CO2 free atmosphere as a function of light and leaf temperature. At constant leaf temperature (30 °C) and CO2 free atmospheres, leaves of the tropical species Inga edulis showed net emissions of CO2 and light-dependent isoprene emissions which stagnated at low light levels (75 µmol m-2 s-1 PAR) and account for 25% of that observed with 450 ppm CO2. Under constant light (1000 µmol m-2 s-1 PAR) and CO2 free atmospheres, a increase of leaf temperatures from 25 to 40 °C resulted in net emissions of CO2 and temperature-dependent isoprene emissions which reached values up to 17% of those under 450 ppm CO2. Our observations suggest that, under environmental stress, as high light/temperature and drought (when the stomata close and the amount of internal CO2 decreases), the 'alternate' carbon can maintain photosynthesis rates resulting in the production of isoprene, independent of atmospheric CO2, through the re-assimilation of internal released CO2 as an 'alternate' carbon sources for isoprene.

  14. Analysis of CO2 emission in traffic flow and numerical tests

    NASA Astrophysics Data System (ADS)

    Zhu, Wen-Xing

    2013-10-01

    We investigated the carbon dioxide emission rate in traffic flow analytically and numerically. The emission model was derived based on Bando’s optimal velocity model with a consideration of slope. Simulations were conducted to examine the relationship between the CO2 emission rate of vehicles and slope of road, traffic density, and road length. Analysis of the results shows that some original laws of CO2 emission in traffic flow with congestion were exhibited.

  15. CO2-C emissions associated to soil tillage, liming and gypsum applications in sugarcane areas under green and burned harvest

    NASA Astrophysics Data System (ADS)

    Figueiredo, E. B.; Panosso, A. R.; La Scala, N., Jr.

    2012-04-01

    Debate regarding the potential of bioenergy crops to substitute fossil fuel in an efficient way is still opened. New management strategies from agricultural crops should be identified to increase their potential contributing to avoid the climate changes. This study quantified the impact of sugarcane harvest systems and other management practices on CO2-C fluxes following crop replanting. Two agricultural systems were considered: burned and green harvest, in plots where residues were left or removed from soil surface, from no till and after conventional tillage, with or without dolomite and agricultural gypsum applications. Soil CO2 emission, moisture and soil temperature were taken since 24 hours after tillage, totalizing 25 days after tillage with 18 measuring days. NT plots emissions were kept lower than others during the whole period studied, presenting in some cases fluctuations which were mostly related to changes in soil moisture associated to the occurrence of rain precipitations. Changes in CO2-C emission, in each of the harvest systems can be clearly seen when tillage, dolomite or gypsum were applied. The removal of sugarcane residues from soil surface resulted in almost immediate reduction of soil moisture (6% in volume) following an increase in soil NT CO2 emission of + 64%. The additional soil carbon emission due to the simple operation of removing the crop residues from soil surface was 252.4 kg CO2-C ha-1, as higher as the soil CO2 losses induced by tillage operation. Dolomite and agricultural gypsum applications did not always result in higher emissions, especially when applied at the presence of crop residues on soil surface. Reducing tillage frequency in green harvested sugarcane areas could reduce CO2 emissions and probably increasing the soil carbon stock considering long-term period crop system, while maintaining the sugarcane crop residues on soil surface has shown to be also a GHG mitigation option.

  16. Peatland CO2 emissions: Using 13C to quantify responses to land use change

    NASA Astrophysics Data System (ADS)

    Snell, Helen; Robinson, David; Midwood, Andrew J.

    2013-04-01

    Soil is the largest terrestrial carbon reservoir and annually soils emit about 98 billion tonnes of CO2which is derived from plant root and rhizosphere respiration (autotrophically fuelled by photosynthesis) and microbial degradation of soil organic carbon (heterotrophic respiration). These two processes are intrinsically linked by complex physical and biochemical interactions. In order to meet its GHG reductions targets the Scottish Government plans to increase woodland cover from 17 to 25% by the second half of this century which will inevitably lead to significant tree planting on peatland soils. Tree roots and associated mycorrhiza will alter physical and biological conditions in the soil which may affect the heterotrophic contribution to CO2 emissions and consequently the long term landscape-scale carbon balance since the difference between net primary productivity and heterotrophic respiration defines the terrestrial CO2 sink. Significant uncertainties surround the response of peatlands to tree planting and predicted climate changes. At a field site in eastern Scotland we used natural abundance stable isotopes of carbon to partition soil CO2 efflux into its heterotrophic and autotrophic components to determine whether young Scots pine plantations affect heterotrophic respiration rates in peatland soil. Rate and isotopic composition of soil CO2 efflux was measured in plantation areas and in unforested heather moorland; soil and roots were then excavated and separately incubated to establish the isotopic end members of a simple linear mixing model. Isotopic composition of soil efflux varies temporally and spatially across the site; young Scots pine trees do not increase the heterotrophic flux from soil and therefore do not lead to a net loss of soil carbon from these landscapes.

  17. Long-term drainage reduces CO2 uptake and increases CO2 emission on a Siberian floodplain due to shifts in vegetation community and soil thermal characteristics

    NASA Astrophysics Data System (ADS)

    Kwon, Min Jung; Heimann, Martin; Kolle, Olaf; Luus, Kristina A.; Schuur, Edward A. G.; Zimov, Nikita; Zimov, Sergey A.; Göckede, Mathias

    2016-07-01

    With increasing air temperatures and changing precipitation patterns forecast for the Arctic over the coming decades, the thawing of ice-rich permafrost is expected to increasingly alter hydrological conditions by creating mosaics of wetter and drier areas. The objective of this study is to investigate how 10 years of lowered water table depths of wet floodplain ecosystems would affect CO2 fluxes measured using a closed chamber system, focusing on the role of long-term changes in soil thermal characteristics and vegetation community structure. Drainage diminishes the heat capacity and thermal conductivity of organic soil, leading to warmer soil temperatures in shallow layers during the daytime and colder soil temperatures in deeper layers, resulting in a reduction in thaw depths. These soil temperature changes can intensify growing-season heterotrophic respiration by up to 95 %. With decreased autotrophic respiration due to reduced gross primary production under these dry conditions, the differences in ecosystem respiration rates in the present study were 25 %. We also found that a decade-long drainage installation significantly increased shrub abundance, while decreasing Eriophorum angustifolium abundance resulted in Carex sp. dominance. These two changes had opposing influences on gross primary production during the growing season: while the increased abundance of shrubs slightly increased gross primary production, the replacement of E. angustifolium by Carex sp. significantly decreased it. With the effects of ecosystem respiration and gross primary production combined, net CO2 uptake rates varied between the two years, which can be attributed to Carex-dominated plots' sensitivity to climate. However, underlying processes showed consistent patterns: 10 years of drainage increased soil temperatures in shallow layers and replaced E. angustifolium by Carex sp., which increased CO2 emission and reduced CO2 uptake rates. During the non-growing season, drainage

  18. Emissions and Atmospheric CO2 Stabilization: Long-Term Limits and Paths

    SciTech Connect

    Kheshgi, Haroon; Smith, Steven J.; Edmonds, James A.

    2005-04-01

    Over the very long term, cumulative CO2 emissions "over all time, by all people" are uniquely related to ultimate atmospheric CO2 concentration level, with limited approximation. A corollary to this relation is that net CO2 emissions must peak and then gradually approach zero over 1,000+ years if a constant CO2 concentration is to be maintained, regardless of the level. The objective of stabilization of greenhouse gas concentrations is often envisioned as a monotonic approach to constant concentrations. But, if emissions decline less gradually to zero, the pattern of transient CO2 concentrations changes to one with a maximum CO2 concentration followed by a long-term decline to a lower level. Such emissionsconcentration trajectories spend a finite time at the maximum concentration and could have smaller overall climate impacts than trajectories that maintain the maximum concentration. Climate impacts in response to such trajectories, however, remain to be studied.

  19. Synergistic control of CO2 emissions by fish and nutrients in a humic tropical lake.

    PubMed

    Marotta, Humberto; Duarte, Carlos M; Guimarães-Souza, Breno A; Enrich-Prast, Alex

    2012-03-01

    Using experimental mesocosms, we tested the strength of bottom-up controls by nutrients and top-down controls by an omnivorous fish (Hyphessobrycon bifasciatus; family Characidae), and the interaction between them on the CO(2) partial pressure (pCO(2)) in the surface waters of a tropical humic lake (Lake Cabiúnas, Brazil). The experiment included the addition of nutrients and fish to the mesocosms in a factorial design. Overall, persistent CO(2) emissions to the atmosphere, supported by an intense net heterotrophy, were observed in all treatments and replicates over the 6-week study period. The CO(2) efflux (average ± standard error) integrated over the experiment was similar among the control mesocosms and those receiving only fish or only nutrients (309 ± 2, 303 ± 16, and 297 ± 17 mmol CO(2) m(-2) day(-1), respectively). However, the addition of nutrients in the presence of fish resulted in a high algal biomass and daytime net autotrophy, reducing the CO(2) emissions by 35% (by 193 ± 7 mmol CO(2) m(-2) day(-1)). These results indicate that high CO(2) emissions persist following the eutrophication of humic waters, but that the magnitude of these emissions might depend on the structure of the food web. In conclusion, fish and nutrients may act in a synergistic manner to modulate persistent CO(2) emissions from tropical humic lakes.

  20. Use of a vehicle-modelling tool for predicting CO 2 emissions in the framework of European regulations for light goods vehicles

    NASA Astrophysics Data System (ADS)

    Fontaras, Georgios; Kouridis, Hariton; Samaras, Zissis; Elst, Daniel; Gense, Raymond

    The reduction of CO 2 emissions and fuel consumption from road transportation constitutes an important pillar of the EU commitment for implementing the Kyoto Protocol. Efforts to monitor and limit CO 2 emissions from vehicles can effectively be supported by the use of vehicle modelling tools. This paper presents the application of such a tool for predicting CO 2 emissions of vehicles under different operating conditions and shows how the results from simulations can be used for supporting policy analysis and design aiming at further reductions of the CO 2 emissions. For this purpose, the case of light duty goods (N1 category) vehicle CO 2 emissions control measures adopted by the EU is analysed. In order to understand how certain design and operating aspects affect fuel consumption, a number of N1 vehicles were simulated with ADVISOR for various operating conditions and the numerical results were validated against chassis dynamometer tests. The model was then employed for analysing and evaluating the new EU legislative framework that addresses CO 2 emissions from this vehicle class. The results of this analysis have shown the weaknesses of the current regulations and revealed new potential in CO 2 emissions control. Finally the TREMOVE model was used for simulating a possible scenario for reducing CO 2 emissions at fleet level.

  1. PHOTOCHEMICAL CO2 REDUCTION BY RHENUIM AND RUTHENIUM COMPLEXES.

    SciTech Connect

    FUJITA,E.; MUCKERMAN, J.T.; TANAKA, K.

    2007-11-30

    Photochemical conversion of CO{sub 2} to fuels or useful chemicals using renewable solar energy is an attractive solution to both the world's need for fuels and the reduction of greenhouse gases. Rhenium(I) and ruthenium(II) diimine complexes have been shown to act as photocatalysts and/or electrocatalysts for CO{sub 2} reduction to CO. We have studied these photochemical systems focusing on the identification of intermediates and the bond formation/cleavage reactions between the metal center and CO{sub 2}. For example, we have produced the one-electron-reduced monomer (i.e. Re(dmb)(CO){sub 3}S where dmb = 4,4'-dimethy-2,2'-bipyridine and S = solvent) either by reductive quenching of the excited states of fac-[Re(dmb)(CO){sub 3}(CH{sub 3}CN)]PF{sub 6} or by photo-induced homolysis of [Re(dmb)(CO){sub 3}]{sub 2}. We previously found that: (1) the remarkably slow dimerization of Re(dmb)(CO){sub 3}S is due to the absence of a vacant coordination site for Re-Re bond formation, and the extra electron is located on the dmb ligand; (2) the reaction of Re(dmb)(CO){sub 3}S with CO{sub 2} forms a CO{sub 2}-bridged binuclear species (CO){sub 3}(dmb)Re-CO(O)-Re(dmb)(CO){sub 3} as an intermediate in CO formation; and (3) the kinetics and mechanism of reactions are consistent with the interaction of the CO{sub 2}-bridged binuclear species with CO{sub 2} to form CO and CO{sub 3}{sup 2-}.

  2. Photoelectrochemical CO2 reduction on 3C-SiC photoanode in aqueous solution

    NASA Astrophysics Data System (ADS)

    Song, Jun Tae; Iwasaki, Takayuki; Hatano, Mutsuko

    2015-04-01

    Photoelectrochemical (PEC) carbon dioxide (CO2) reduction on a 3C-SiC photoanode is demonstrated in aqueous solution with Pt and Ag counter electrodes. It is demonstrated that 3C-SiC has sufficient potential for CO2 reduction by confirming the band-edge structure. Then, the CO2 reduction is realized by connecting the 3C-SiC photoanode with the counter electrode. As the products of the PEC reaction with an applied bias of 1 V (vs counter electrode) to the 3C-SiC photoanode, hydrogen (H2) and carbon monoxide (CO) were analyzed by highly sensitive micro-gas chromatography, by which the time dependence of the gas products can be analyzed. Under light illumination of the 3C-SiC photoanode, CO2 reduction occurred while producing 2.5 and 9 nmol of CO gas with the Pt and Ag counter electrodes, respectively, after the reaction for 3000 s.

  3. Stratospheric ozone response to a solar irradiance reduction in a quadrupled CO2 environment

    NASA Astrophysics Data System (ADS)

    Jackman, Charles H.; Fleming, Eric L.

    2014-07-01

    We used the Goddard Space Flight Center (GSFC) global two-dimensional (2D) atmospheric model to investigate the stratospheric ozone response to a proposed geoengineering activity wherein a reduced top-of-atmosphere (TOA) solar irradiance is imposed to help counteract a quadrupled CO2 atmosphere. This study is similar to the Geoengineering Model Intercomparison Project (GeoMIP) Experiment G1. Three primary simulations were completed with the GSFC 2D model to examine this possibility: (A) a pre-industrial atmosphere with a boundary condition of 285 ppmv CO2 (piControl); (B) a base future atmosphere with 1140 ppmv CO2 (abrupt4xCO2); and (C) a perturbed future atmosphere with 1140 ppmv CO2 and a 4% reduction in the TOA total solar irradiance (G1). We found huge ozone enhancements throughout most of the stratosphere (up to 40%) as a result of a large computed temperature decrease (up to 18 K) when CO2 was quadrupled (compare simulation abrupt4xCO2 to piControl). Further, we found that ozone will additionally increase (up to 5%) throughout most of the stratosphere with total ozone increases of 1-2.5% as a result of a reduction in TOA total solar irradiance (compare simulation G1 to abrupt4xCO2). Decreases of atomic oxygen and temperature are the main drivers of this computed ozone enhancement from a reduction in TOA total solar irradiance.

  4. The CO2 Reduction Potential of Combined Heat and Power in California's Commercial Buildings

    SciTech Connect

    Stadler, Michael; Marnay, Chris; Cardoso, Goncalo; Lipman, Tim; Megel, Olivier; Ganguly, Srirupa; Siddiqui, Afzal; Lai, Judy

    2009-11-16

    The Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) is working with the California Energy Commission (CEC) to determine the potential role of commercial sector distributed generation (DG) with combined heat and power (CHP) capability deployment in greenhouse gas emissions (GHG) reductions. CHP applications at large industrial sites are well known, and a large share of their potential has already been harvested. In contrast, relatively little attention has been paid to the potential of medium-sized commercial buildings, i.e., ones with peak electric loads ranging from 100 kW to 5 MW. We examine how this sector might implement DG with CHP in cost minimizing microgrids that are able to adopt and operate various energy technologies, such as solar photovoltaics (PV), on-site thermal generation, heat exchangers, solar thermal collectors, absorption chillers, and storage systems. We apply a mixed-integer linear program (MILP) that minimizes a site's annual energy costs as its objective. Using 138 representative mid-sized commercial sites in California (CA), existing tariffs of three major electricity distribution ultilities plus a natural gas company, and performance data of available technology in 2020, we find the GHG reduction potential for this CA commercial sector segment, which represents about 35percent of total statewide commercial sector sales. Under the assumptions made, in a reference case, this segment is estimated to be capable of economically installing 1.4 GW of CHP, 35percent of the California Air Resources Board (CARB) statewide 4 GW goal for total incremental CHP deployment by 2020. However, because CARB's assumed utilization is far higherthan is found by the MILP, the adopted CHP only contributes 19percent of the CO2 target. Several sensitivity runs were completed. One applies a simple feed-in tariff similar to net metering, and another includes a generous self-generation incentive program (SGIP) subsidy for fuel cells. The feed-in tariff

  5. Quantification of anthropogenic CO2 emissions in a tropical urban environment

    NASA Astrophysics Data System (ADS)

    Kumar, M. Kishore; Shiva Nagendra, S. M.

    2016-01-01

    Indian cities are the hotspots of human population with population densities as high as 66,135 persons/sq km and are hence emerging as one of the significant CO2 emitters on par with cities of the developed nations. In this regard, quantification of Indian urban CO2 emissions at a finer resolution of space and time is becoming a crucial prerequisite for the implementation of India's National Action Plan on Climate Change. This paper presents the quantification of CO2 emissions of Chennai city at a fine spatial (1 km × 1 km) and temporal (diurnal, weekday-weekend, seasonal) resolution. In the present study, data sets of residential, industrial, commercial, traffic and waste management sectors were considered and bottom up approach was used for quantifying the CO2 emissions. Results indicated that the total annual CO2 emission of Chennai city was 2.12 Mt. Domestic (45.7%) and transportation (29.7%) sectors were identified as the larger CO2 emitters followed by power generation sector (17.4%). The average grid wise anthropogenic CO2 emission was found to be 0.01 ± 0.02 Mt/yr with peak CO2 emissions observed from the grids with point sources and minimal CO2 emissions from the grids overlaying on the urban forest of the city. The average per capita CO2 emission of Chennai was found to be 0.45 tons/yr which is less than the national per capita CO2 emission of 1.6 tons/year. The estimated CO2 fluxes due to anthropogenic emissions were in the range of 0-8.5 × 10-6 kg/m2/s with an average flux of 0.36 × 10-6 kg/m2/s. CO2 emissions during weekdays and weekends in summer season (5862.6 and 6235.58 tons/day) were slightly higher than in winter season (5540.8 and 5929.6 tons/day). Grids overlaying on commercial and residential zones showed higher CO2 emissions during morning (07:00-10:00 AM) and evening rush hours (07:00-09:00 PM) of a day.

  6. Integrated model for assessing the cost and CO2 emission (IMACC) for sustainable structural design in ready-mix concrete.

    PubMed

    Hong, Taehoon; Ji, Changyoon; Park, Hyoseon

    2012-07-30

    Cost has traditionally been considered the most important factor in the decision-making process. Recently, along with the consistent interest in environmental problems, environmental impact has also become a key factor. Accordingly, there is a need to develop a method that simultaneously reflects the cost and environmental impact in the decision-making process. This study proposed an integrated model for assessing the cost and CO(2) emission (IMACC) at the same time. IMACC is a model that assesses the cost and CO(2) emission of the various structural-design alternatives proposed in the structural-design process. To develop the IMACC, a standard on assessing the cost and CO(2) emission generated in the construction stage was proposed, along with the CO(2) emission factors in the structural materials, based on such materials' strengths. Moreover, using the economic and environmental scores that signify the cost and CO(2) emission reduction ratios, respectively, a method of selecting the best design alternative was proposed. To verify the applicability of IMACC, practical application was carried out. Structural designs were assessed, each of which used 21, 24, 27, and 30 MPa ready-mix concrete (RMC). The use of IMACC makes it easy to verify what the best design is. Results show the one that used 27 MPa RMC was the best design. Therefore, the proposed IMACC can be used as a tool for supporting the decision-making process in selecting the best design alternative. PMID:22436837

  7. An internal electron reservoir enhances catalytic CO2 reduction by a semisynthetic enzyme.

    PubMed

    Schneider, Camille R; Shafaat, Hannah S

    2016-08-01

    The development of an artificial metalloenzyme for CO2 reduction is described. The small-molecule catalyst [Ni(II)(cyclam)](2+) has been incorporated within azurin. Selectivity for CO generation over H(+) reduction is enhanced within the protein environment, while the azurin active site metal impacts the electrochemical overpotential and photocatalytic activity. The enhanced catalysis observed for copper azurin suggests an important role for intramolecular electron transfer, analogous to native CO2 reducing enzymes. PMID:27406946

  8. Final report : CO2 reduction using biomimetic photocatalytic nanodevices.

    SciTech Connect

    Garcia, Robert M.; Shelnutt, John Allen; Medforth, Craig John; Song, Yujiang; Wang, Zhongchun; Miller, James Edward; Wang, Haorong

    2009-11-01

    Nobel Prize winner Richard Smalley was an avid champion for the cause of energy research. Calling it 'the single most important problem facing humanity today,' Smalley promoted the development of nanotechnology as a means to harness solar energy. Using nanotechnology to create solar fuels (i.e., fuels created from sunlight, CO{sub 2}, and water) is an especially intriguing idea, as it impacts not only energy production and storage, but also climate change. Solar irradiation is the only sustainable energy source of a magnitude sufficient to meet projections for global energy demand. Biofuels meet the definition of a solar fuel. Unfortunately, the efficiency of photosynthesis will need to be improved by an estimated factor of ten before biofuels can fully replace fossil fuels. Additionally, biological organisms produce an array of hydrocarbon products requiring further processing before they are usable for most applications. Alternately, 'bio-inspired' nanostructured photocatalytic devices that efficiently harvest sunlight and use that energy to reduce CO{sub 2} into a single useful product or chemical intermediate can be envisioned. Of course, producing such a device is very challenging as it must be robust and multifunctional, i.e. capable of promoting and coupling the multi-electron, multi-photon water oxidation and CO{sub 2} reduction processes. Herein, we summarize some of the recent and most significant work towards creating light harvesting nanodevices that reduce CO{sub 2} to CO (a key chemical intermediate) that are based on key functionalities inspired by nature. We report the growth of Co(III)TPPCl nanofibers (20-100 nm in diameter) on gas diffusion layers via an evaporation induced self-assembly (EISA) method. Remarkably, as-fabricated electrodes demonstrate light-enhanced activity for CO{sub 2} reduction to CO as evidenced by cyclic voltammograms and electrolysis with/without light irradiation. To the best of our knowledge, it is the first time to

  9. Spatiotemporal Characteristics, Determinants and Scenario Analysis of CO2 Emissions in China Using Provincial Panel Data

    PubMed Central

    Wang, Shaojian

    2015-01-01

    This paper empirically investigated the spatiotemporal variations, influencing factors and future emission trends of China’s CO2 emissions based on a provincial panel data set. A series of panel econometric models were used taking the period 1995–2011 into consideration. The results indicated that CO2 emissions in China increased over time, and were characterized by noticeable regional discrepancies; in addition, CO2 emissions also exhibited properties of spatial dependence and convergence. Factors such as population scale, economic level and urbanization level exerted a positive influence on CO2 emissions. Conversely, energy intensity was identified as having a negative influence on CO2 emissions. In addition, the significance of the relationship between CO2 emissions and the four variables varied across the provinces based on their scale of economic development. Scenario simulations further showed that the scenario of middle economic growth, middle population increase, low urbanization growth, and high technology improvement (here referred to as Scenario BTU), constitutes the best development model for China to realize the future sustainable development. Based on these empirical findings, we also provide a number of policy recommendations with respect to the future mitigation of CO2 emissions. PMID:26397373

  10. Spatiotemporal Characteristics, Determinants and Scenario Analysis of CO2 Emissions in China Using Provincial Panel Data.

    PubMed

    Wang, Shaojian; Fang, Chuanglin; Li, Guangdong

    2015-01-01

    This paper empirically investigated the spatiotemporal variations, influencing factors and future emission trends of China's CO2 emissions based on a provincial panel data set. A series of panel econometric models were used taking the period 1995-2011 into consideration. The results indicated that CO2 emissions in China increased over time, and were characterized by noticeable regional discrepancies; in addition, CO2 emissions also exhibited properties of spatial dependence and convergence. Factors such as population scale, economic level and urbanization level exerted a positive influence on CO2 emissions. Conversely, energy intensity was identified as having a negative influence on CO2 emissions. In addition, the significance of the relationship between CO2 emissions and the four variables varied across the provinces based on their scale of economic development. Scenario simulations further showed that the scenario of middle economic growth, middle population increase, low urbanization growth, and high technology improvement (here referred to as Scenario BTU), constitutes the best development model for China to realize the future sustainable development. Based on these empirical findings, we also provide a number of policy recommendations with respect to the future mitigation of CO2 emissions.

  11. Diurnal sampling reveals significant variation in CO2 emission from a tropical productive lake.

    PubMed

    Reis, P C J; Barbosa, F A R

    2014-08-01

    It is well accepted in the literature that lakes are generally net heterotrophic and supersaturated with CO2 because they receive allochthonous carbon inputs. However, autotrophy and CO2 undersaturation may happen for at least part of the time, especially in productive lakes. Since diurnal scale is particularly important to tropical lakes dynamics, we evaluated diurnal changes in pCO2 and CO2 flux across the air-water interface in a tropical productive lake in southeastern Brazil (Lake Carioca) over two consecutive days. Both pCO2 and CO2 flux were significantly different between day (9:00 to 17:00) and night (21:00 to 5:00) confirming the importance of this scale for CO2 dynamics in tropical lakes. Net heterotrophy and CO2 outgassing from the lake were registered only at night, while significant CO2 emission did not happen during the day. Dissolved oxygen concentration and temperature trends over the diurnal cycle indicated the dependence of CO2 dynamics on lake metabolism (respiration and photosynthesis). This study indicates the importance of considering the diurnal scale when examining CO2 emissions from tropical lakes.

  12. CO2 emissions from organic soils under agricultural use

    NASA Astrophysics Data System (ADS)

    Bader, Cédric; Leifeld, Jens; Müller, Moritz; Schulin, Rainer

    2015-04-01

    The organic soils of peatlands represent a major global sink for terrestrial carbon. Agricultural use of organic soils requires drainage, changing conditions in these soils from anoxic to oxic. As a consequence, the organic carbon that had been accumulated often over millennia is rapidly mineralized, so that these soils then are no longer a sink but become a source of CO2. The aim of our study is to analyse the amount and origin of CO2 emitted from organic soils under three land-use types (forest, arable cropland and grassland). Our study area is located in the Bernese Lakeland (CH). The peatlands of this region were drained in the 1870ies, and the site as well as the surrounding area are now managed by a state prison. Since decades our study site is under the same land-use. In Oktober 2013 we took 4 replicate soil cores of all land-uses with respect to a certain distance from a major drainage ditch. Each core was analysed for its bulk density and carbon content. 9 soil samples from a depth of 20-30 cm were analysed for their F14C and δ13C values and later divided into 18 subsamples. Half of them were mixed with 0.2-0.4 g of labelled corn stalk enriched in δ13C (δ13C=2000) in order to mimic plant residue inputs in the field. The moisture content of these samples was equilibrated at a pF-value of 2 before incubating the samples in a Respicond VII analyser for several weeks at 20° C. By trapping the respired CO2 in NaOH and precipitating it as BaCO3 we were able to analyse its F14C and δ13C value. This enabled us to determine to what extent the CO2 originated from old peat, young plant residues or the added maize stalk. Generally the cropland samples showed the highest respiration rates, lowest F14C values and highest carbon stocks. The organic soils under the forest were degraded the most and showed low respiration rates. Analyzing the F14C values of the CO2 revealed that peat contributes most to the respiration and its degradation is fastest in the cropland

  13. Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions.

    PubMed

    Nagelkerken, Ivan; Connell, Sean D

    2015-10-27

    Rising anthropogenic CO2 emissions are anticipated to drive change to ocean ecosystems, but a conceptualization of biological change derived from quantitative analyses is lacking. Derived from multiple ecosystems and latitudes, our metaanalysis of 632 published experiments quantified the direction and magnitude of ecological change resulting from ocean acidification and warming to conceptualize broadly based change. Primary production by temperate noncalcifying plankton increases with elevated temperature and CO2, whereas tropical plankton decreases productivity because of acidification. Temperature increases consumption by and metabolic rates of herbivores, but this response does not translate into greater secondary production, which instead decreases with acidification in calcifying and noncalcifying species. This effect creates a mismatch with carnivores whose metabolic and foraging costs increase with temperature. Species diversity and abundances of tropical as well as temperate species decline with acidification, with shifts favoring novel community compositions dominated by noncalcifiers and microorganisms. Both warming and acidification instigate reduced calcification in tropical and temperate reef-building species. Acidification leads to a decline in dimethylsulfide production by ocean plankton, which as a climate gas, contributes to cloud formation and maintenance of the Earth's heat budget. Analysis of responses in short- and long-term experiments and of studies at natural CO2 vents reveals little evidence of acclimation to acidification or temperature changes, except for microbes. This conceptualization of change across whole communities and their trophic linkages forecast a reduction in diversity and abundances of various key species that underpin current functioning of marine ecosystems. PMID:26460052

  14. Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions

    PubMed Central

    Nagelkerken, Ivan; Connell, Sean D.

    2015-01-01

    Rising anthropogenic CO2 emissions are anticipated to drive change to ocean ecosystems, but a conceptualization of biological change derived from quantitative analyses is lacking. Derived from multiple ecosystems and latitudes, our metaanalysis of 632 published experiments quantified the direction and magnitude of ecological change resulting from ocean acidification and warming to conceptualize broadly based change. Primary production by temperate noncalcifying plankton increases with elevated temperature and CO2, whereas tropical plankton decreases productivity because of acidification. Temperature increases consumption by and metabolic rates of herbivores, but this response does not translate into greater secondary production, which instead decreases with acidification in calcifying and noncalcifying species. This effect creates a mismatch with carnivores whose metabolic and foraging costs increase with temperature. Species diversity and abundances of tropical as well as temperate species decline with acidification, with shifts favoring novel community compositions dominated by noncalcifiers and microorganisms. Both warming and acidification instigate reduced calcification in tropical and temperate reef-building species. Acidification leads to a decline in dimethylsulfide production by ocean plankton, which as a climate gas, contributes to cloud formation and maintenance of the Earth’s heat budget. Analysis of responses in short- and long-term experiments and of studies at natural CO2 vents reveals little evidence of acclimation to acidification or temperature changes, except for microbes. This conceptualization of change across whole communities and their trophic linkages forecast a reduction in diversity and abundances of various key species that underpin current functioning of marine ecosystems. PMID:26460052

  15. Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions.

    PubMed

    Nagelkerken, Ivan; Connell, Sean D

    2015-10-27

    Rising anthropogenic CO2 emissions are anticipated to drive change to ocean ecosystems, but a conceptualization of biological change derived from quantitative analyses is lacking. Derived from multiple ecosystems and latitudes, our metaanalysis of 632 published experiments quantified the direction and magnitude of ecological change resulting from ocean acidification and warming to conceptualize broadly based change. Primary production by temperate noncalcifying plankton increases with elevated temperature and CO2, whereas tropical plankton decreases productivity because of acidification. Temperature increases consumption by and metabolic rates of herbivores, but this response does not translate into greater secondary production, which instead decreases with acidification in calcifying and noncalcifying species. This effect creates a mismatch with carnivores whose metabolic and foraging costs increase with temperature. Species diversity and abundances of tropical as well as temperate species decline with acidification, with shifts favoring novel community compositions dominated by noncalcifiers and microorganisms. Both warming and acidification instigate reduced calcification in tropical and temperate reef-building species. Acidification leads to a decline in dimethylsulfide production by ocean plankton, which as a climate gas, contributes to cloud formation and maintenance of the Earth's heat budget. Analysis of responses in short- and long-term experiments and of studies at natural CO2 vents reveals little evidence of acclimation to acidification or temperature changes, except for microbes. This conceptualization of change across whole communities and their trophic linkages forecast a reduction in diversity and abundances of various key species that underpin current functioning of marine ecosystems.

  16. Tracking and verifying anthropogenic CO2 emissions over the Swiss Plateau

    NASA Astrophysics Data System (ADS)

    Oney, Brian; Brunner, Dominik; Henne, Stephan; Leuenberger, Markus

    2013-04-01

    The Swiss Plateau is the densely populated and industrialized part of Switzerland producing more than 90% of the country's total greenhouse gas emissions. Verification of the efficacy of emission mitigation measures in a post Kyoto Protocol era will require several levels of scrutiny at local and regional scales. We present a measurement and modeling system, which quantifies anthropogenic CO2 emissions at a regional scale using the Lagrangian particle dispersion model FLEXPART driven by output from a high-resolution regional scale atmospheric model (COSMO) and observations from two tall tower sites. These rural measurement sites are situated between the largest cities of Switzerland (Zürich, Geneva, Basel and Bern). We present methods used to discretize the anthropogenic CO2 signal from atmospheric CO2 measurements. First, we perform high resolution, time-inverted simulations of air transport combined with a new high quality Swiss CO2 emissions inventory to determine a model-estimated anthropogenic portion of the measured CO2. Second, we assess the utility of CO measurements and the relationship between CO2 and CO in combustion processes as a proxy to quantify the anthropogenic CO2 fraction directly from the measurements. We then compare these two methods in their ability to determine the anthropogenic portion of CO2 measurements at a high temporal resolution (hours). Finally, we assess the quality of the simulated atmospheric transport by comparing CO concentrations obtained with the same atmospheric transport model and a high resolution CO emission inventory with the measured CO concentrations. This comparison of methods for determining anthropogenic CO2 emissions provides information on how to independently certify reported CO2 emissions. This study is a first step towards a prototype GHG monitoring and verification system for the regional scale in a complex topographic setting, which constitutes a necessary component of emissions reporting.

  17. [Impact of Phosphogypsum Wastes on the Wheat Growth and CO2 Emissions and Evaluation of Economic-environmental Benefit].

    PubMed

    Li, Ji; Wu, Hong-sheng; Gao, Zhi-qiu; Shang, Xiao-xia; Zheng, Pei-hui; Yin, Jin; Kakpa, Didier; Ren, Qian-qi; Faustin, Ogou Katchele; Chen, Su-yun; Xu, Ya; Yao, Tong-yan; Ji, Wei; Qian, Jing-shan; Ma, Shi-jie

    2015-08-01

    Phosphogypsum is a phosphorus chemical waste which has not been managed and reused well, resultantly, causing environmental pollution and land-occupation. Phosphogypsum wastes were used as a soil amendment to assess the effect on wheat growth, yield and CO2 emissions from winter wheat fields. Its economic and environmental benefits were analyzed at the same time. The results showed that wheat yield was increased by 37.71% in the treatment of phosphogypsum of 2 100 kg x hm(-2). Compared with the control treatment, throughout the wheat growing season, CO2 emission was accumulatively reduced by 3% in the treatment of phosphogypsum waste of 1050 kg x hm(-2), while reduced by 8% , 10% , and 6% during the jointing stage, heading date and filling period of wheat, respectively; while CO2 emission was accumulatively reduced by 7% in the treatment of phosphogypsum waste of 2 100 kg x hm(-2) throughout the wheat growing season, as reduced by 11% , 4% , and 12% during the reviving wintering stage, heading date and filling period of wheat, respectively. It was better for CO2 emission reduction in the treatment of a larger amount of phosphogypsum waste. In the case of application of phosphogypsum waste residue within a certain range, the emission intensity of CO2 ( CO2 emissions of per unit of fresh weight or CO2 emissions of per unit of yield) , spike length, fresh weight and yield showed a significantly negative correlation--the longer the ear length, the greater fresh weight and yield and the lower the CO2 emissions intensity. As to the carbon trading, phosphogypsum utilization was of high economic and environmental benefits. Compared with the control, the ratio of input to output changed from 1: 8.3 to 1: 10.7, which in the same situation of investment the output could be increased by 28.92% ; phosphogypsum as a greenhouse gas reducing agent in the wheat field, it could decrease the cost and increase the environmental benefit totally about 290 yuan per unit of ton. The

  18. [Impact of Phosphogypsum Wastes on the Wheat Growth and CO2 Emissions and Evaluation of Economic-environmental Benefit].

    PubMed

    Li, Ji; Wu, Hong-sheng; Gao, Zhi-qiu; Shang, Xiao-xia; Zheng, Pei-hui; Yin, Jin; Kakpa, Didier; Ren, Qian-qi; Faustin, Ogou Katchele; Chen, Su-yun; Xu, Ya; Yao, Tong-yan; Ji, Wei; Qian, Jing-shan; Ma, Shi-jie

    2015-08-01

    Phosphogypsum is a phosphorus chemical waste which has not been managed and reused well, resultantly, causing environmental pollution and land-occupation. Phosphogypsum wastes were used as a soil amendment to assess the effect on wheat growth, yield and CO2 emissions from winter wheat fields. Its economic and environmental benefits were analyzed at the same time. The results showed that wheat yield was increased by 37.71% in the treatment of phosphogypsum of 2 100 kg x hm(-2). Compared with the control treatment, throughout the wheat growing season, CO2 emission was accumulatively reduced by 3% in the treatment of phosphogypsum waste of 1050 kg x hm(-2), while reduced by 8% , 10% , and 6% during the jointing stage, heading date and filling period of wheat, respectively; while CO2 emission was accumulatively reduced by 7% in the treatment of phosphogypsum waste of 2 100 kg x hm(-2) throughout the wheat growing season, as reduced by 11% , 4% , and 12% during the reviving wintering stage, heading date and filling period of wheat, respectively. It was better for CO2 emission reduction in the treatment of a larger amount of phosphogypsum waste. In the case of application of phosphogypsum waste residue within a certain range, the emission intensity of CO2 ( CO2 emissions of per unit of fresh weight or CO2 emissions of per unit of yield) , spike length, fresh weight and yield showed a significantly negative correlation--the longer the ear length, the greater fresh weight and yield and the lower the CO2 emissions intensity. As to the carbon trading, phosphogypsum utilization was of high economic and environmental benefits. Compared with the control, the ratio of input to output changed from 1: 8.3 to 1: 10.7, which in the same situation of investment the output could be increased by 28.92% ; phosphogypsum as a greenhouse gas reducing agent in the wheat field, it could decrease the cost and increase the environmental benefit totally about 290 yuan per unit of ton. The

  19. Use of Chia Plant to Monitor Urban Fossil Fuel CO2 Emission: An Example From Irvine, CA in 2010

    NASA Astrophysics Data System (ADS)

    Xu, X.; Stills, A.; Trumbore, S.; Randerson, J. T.; Yi, J.

    2011-12-01

    Δ14CO2 is a unique tracer for quantifying anthropogenic CO2 emissions. However, monitoring 14CO2 change and distribution in an urban environment is challenging because of its large spatial and temporal variations. We have tested the potential use of a chia plant (Salvia hispanica) as an alternative way to collect a time-integrated CO2 sample for radiocarbon analysis. The results show that Δ14C of the new growth of chia sprouts and chia leaves are consistent with the Δ14C of air samples collected during the growing period, indicating the new growth has no inherited C from seeds and thus records atmospheric 14CO2. Time-integrated air samples and chia leaf samples significantly reduced the noises of Δ14CO2 in an urban environment. We report here an example of monitoring 14CO2 change in Irvine, CA from Mar 2010 to Mar 2011 utilizing such a method. The results showed a clear seasonal cycle with high (close to remote air background level) Δ14C in summer and low Δ14C in winter months in this urban area. Excess (above remote air background) fossil fuel CO2 was calculated to be closed to 0 ppm in June to about 16 ppm from November 2010 to February 2011. Monthly mean Δ14CO2 was anti-correlated with monthly mean CO mixing ratio, indicating Δ14CO2 is mainly controlled by fossil fuel CO2 mixing with clean on-shore marine air. In summary, this study has shown encouraging result that chia plant can be potentially used as a convenient and inexpensive sampling method for time-integrated atmospheric 14CO2. Combined with other annual plants this provides the opportunity to map out time-integrated fossil fuel-derived CO2 in major cities at low cost. This in turn can be used to: 1) establish a baseline for fossil fuel emissions reductions in cities in the future; 2) provide invaluable information for validating emission models.

  20. Directed Assembly of Nanoparticle Catalysts on Nanowire Photoelectrodes for Photoelectrochemical CO2 Reduction.

    PubMed

    Kong, Qiao; Kim, Dohyung; Liu, Chong; Yu, Yi; Su, Yude; Li, Yifan; Yang, Peidong

    2016-09-14

    Reducing carbon dioxide with a multicomponent artificial photosynthetic system, closely mimicking nature, represents a promising approach for energy storage. Previous works have focused on exploiting light-harvesting semiconductor nanowires (NW) for photoelectrochemical water splitting. With the newly developed CO2 reduction nanoparticle (NP) catalysts, direct interfacing of these nanocatalysts with NW light absorbers for photoelectrochemical reduction of CO2 becomes feasible. Here, we demonstrate a directed assembly of NP catalysts on vertical NW substrates for CO2-to-CO conversion under illumination. Guided by the one-dimensional geometry, well-dispersed assembly of Au3Cu NPs on the surface of Si NW arrays was achieved with facile coverage tunability. Such Au3Cu NP decorated Si NW arrays can readily serve as effective CO2 reduction photoelectrodes, exhibiting high CO2-to-CO selectivity close to 80% at -0.20 V vs RHE with suppressed hydrogen evolution. A reduction of 120 mV overpotential compared to the planar (PL) counterpart was observed resulting from the optimized spatial arrangement of NP catalysts on the high surface area NW arrays. In addition, this system showed consistent photoelectrochemical CO2 reduction capability up to 18 h. This simple photoelectrode assembly process will lead to further progress in artificial photosynthesis, by allowing the combination of developments in each subfield to create an efficient light-driven system generating carbon-based fuels. PMID:27494433

  1. Directed Assembly of Nanoparticle Catalysts on Nanowire Photoelectrodes for Photoelectrochemical CO2 Reduction.

    PubMed

    Kong, Qiao; Kim, Dohyung; Liu, Chong; Yu, Yi; Su, Yude; Li, Yifan; Yang, Peidong

    2016-09-14

    Reducing carbon dioxide with a multicomponent artificial photosynthetic system, closely mimicking nature, represents a promising approach for energy storage. Previous works have focused on exploiting light-harvesting semiconductor nanowires (NW) for photoelectrochemical water splitting. With the newly developed CO2 reduction nanoparticle (NP) catalysts, direct interfacing of these nanocatalysts with NW light absorbers for photoelectrochemical reduction of CO2 becomes feasible. Here, we demonstrate a directed assembly of NP catalysts on vertical NW substrates for CO2-to-CO conversion under illumination. Guided by the one-dimensional geometry, well-dispersed assembly of Au3Cu NPs on the surface of Si NW arrays was achieved with facile coverage tunability. Such Au3Cu NP decorated Si NW arrays can readily serve as effective CO2 reduction photoelectrodes, exhibiting high CO2-to-CO selectivity close to 80% at -0.20 V vs RHE with suppressed hydrogen evolution. A reduction of 120 mV overpotential compared to the planar (PL) counterpart was observed resulting from the optimized spatial arrangement of NP catalysts on the high surface area NW arrays. In addition, this system showed consistent photoelectrochemical CO2 reduction capability up to 18 h. This simple photoelectrode assembly process will lead to further progress in artificial photosynthesis, by allowing the combination of developments in each subfield to create an efficient light-driven system generating carbon-based fuels.

  2. Decreasing emissions of NOx relative to CO2 in East Asia inferred from satellite observations

    NASA Astrophysics Data System (ADS)

    Reuter, M.; Buchwitz, M.; Hilboll, A.; Richter, A.; Schneising, O.; Hilker, M.; Heymann, J.; Bovensmann, H.; Burrows, J. P.

    2014-11-01

    At present, global CO2 emission inventories are mainly based on bottom-up estimates that rely, for example, on reported fossil fuel consumptions and fuel types. The associated uncertainties propagate into the CO2-to-NOx emission ratios that are used in pollution prediction and monitoring, as well as into biospheric carbon fluxes derived by inverse models. Here we analyse simultaneous and co-located satellite retrievals from SCIAMACHY (ref. ; SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) of the column-average dry-air mole fraction of CO2 (refs , ) and NO2 (refs , , ) for the years 2003-2011 to provide a top-down estimate of trends in emissions and in the ratio between CO2 and NOx emissions. Our analysis shows that the CO2-to-NOx emission ratio has increased by 4.2 +/- 1.7% yr-1 in East Asia. In this region, we find a large positive trend of CO2 emissions (9.8 +/- 1.7% yr-1), which we largely attribute to the growing Chinese economy. This trend exceeds the positive trend of NOx emissions (5.8 +/- 0.9% yr-1). Our findings suggest that the recently installed and renewed technology in East Asia, such as power plants, transportation and so on, is cleaner in terms of NOx emissions than the old infrastructure, and roughly matches relative emission levels in North America and Europe.

  3. Geochemical signatures of the diffuse CO2 emission from Brava volcanic system, Cape Verde

    NASA Astrophysics Data System (ADS)

    Rodriguez, F.; Bandomo, Z.; Barros, I.; Dias Fonseca, J.; Fernandes, P.; Rodrigues, J.; Melian Rodriguez, G.; Padron, E.; Dionis, S.; Sonia, S.; Gonçalves, A.; Fernandes, A.; Hernandez Perez, P. A.; Perez, N.

    2010-12-01

    Brava (67 km2) the smallest of the populated Cape Verde islands, lies at the southwestern end of the archipelagic crescent. Brava volcanic system has no documented historical eruptions, but its youthful volcanic morphology and the fact that earthquake swarms still occur indicate the potential for future eruptions. A geochemical survey of diffuse gas emissions was carried out in Brava island during February and March 2010. For this survey 228 sampling sites were selected all over the island to perform soil CO2 efflux measurements, using a portable accumulation chamber and an IR sensor, and soil temperature measurements at a depth of 30-50 cm. Soil gas samples were collected at 40 cm depth for chemical (He, H2, N2, CO2, CH4, Ar and O2) and isotopic (δ13C-CO2) analysis in 32 selected sampling sites. CO2 efflux values ranged from non-detectable up to 1.343 g m-2 d-1. To quantify the total diffuse CO2 emission from Brava volcanic system, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (˜2 g m-2 d-1), while peak levels (>1300 g m-2 d-1) were mainly identified at Vinagre and Baleia areas. The total diffuse CO2 output from Brava volcanic system was estimated about 41.6 t d-1. The analysis of the carbon isotopic signature of the CO2 in the soil atmosphere provides an insight for evaluating the origin of the diffuse CO2 emission. Observed δ13C-CO2 values ranged from -20.86 to -1.26 ‰. A binary plot of CO2 concentrations versus δ13C-CO2 values allows us to represent three major geochemical reservoirs (atmospheric air, volcanic gas, and biogenic gas) and their related mixing lines. The chemical and isotopic analysis of Brava soil gas samples suggest a mixing with deep-seated CO2 and biogenic gas for the diffuse CO2 emission from Brava volcanic system. The lack of visible volcanic gas emission in Brava highlights the importance of monitoring diffuse CO2 emission to improve its

  4. Electrochemical CO2 Reduction - A Critical View on Fundamentals, Materials and Applications.

    PubMed

    Durst, Julien; Rudnev, Alexander; Dutta, Abhijit; Fu, Yongchun; Herranz, Juan; Kaliginedi, Veerabhadrarao; Kuzume, Akiyoshi; Permyakova, Anastasia A; Paratcha, Yohan; Broekmann, Peter; Schmidt, Thomas J

    2015-01-01

    The electrochemical reduction of CO(2) has been extensively studied over the past decades. Nevertheless, this topic has been tackled so far only by using a very fundamental approach and mostly by trying to improve kinetics and selectivities toward specific products in half-cell configurations and liquid-based electrolytes. The main drawback of this approach is that, due to the low solubility of CO(2) in water, the maximum CO(2) reduction current which could be drawn falls in the range of 0.01-0.02 A cm(-2). This is at least an order of magnitude lower current density than the requirement to make CO(2)-electrolysis a technically and economically feasible option for transformation of CO(2) into chemical feedstock or fuel thereby closing the CO(2) cycle. This work attempts to give a short overview on the status of electrochemical CO(2) reduction with respect to challenges at the electrolysis cell as well as at the catalyst level. We will critically discuss possible pathways to increase both operating current density and conversion efficiency in order to close the gap with established energy conversion technologies.

  5. Does Size Matter? Scaling of CO2 Emissions and U.S. Urban Areas

    PubMed Central

    Fragkias, Michail; Lobo, José; Strumsky, Deborah; Seto, Karen C.

    2013-01-01

    Urban areas consume more than 66% of the world’s energy and generate more than 70% of global greenhouse gas emissions. With the world’s population expected to reach 10 billion by 2100, nearly 90% of whom will live in urban areas, a critical question for planetary sustainability is how the size of cities affects energy use and carbon dioxide (CO2) emissions. Are larger cities more energy and emissions efficient than smaller ones? Do larger cities exhibit gains from economies of scale with regard to emissions? Here we examine the relationship between city size and CO2 emissions for U.S. metropolitan areas using a production accounting allocation of emissions. We find that for the time period of 1999–2008, CO2 emissions scale proportionally with urban population size. Contrary to theoretical expectations, larger cities are not more emissions efficient than smaller ones. PMID:23750213

  6. Does size matter? Scaling of CO2 emissions and US urban areas.

    PubMed

    Fragkias, Michail; Lobo, José; Strumsky, Deborah; Seto, Karen C

    2013-01-01

    Urban areas consume more than 66% of the world's energy and generate more than 70% of global greenhouse gas emissions. With the world's population expected to reach 10 billion by 2100, nearly 90% of whom will live in urban areas, a critical question for planetary sustainability is how the size of cities affects energy use and carbon dioxide (CO2) emissions. Are larger cities more energy and emissions efficient than smaller ones? Do larger cities exhibit gains from economies of scale with regard to emissions? Here we examine the relationship between city size and CO2 emissions for U.S. metropolitan areas using a production accounting allocation of emissions. We find that for the time period of 1999-2008, CO2 emissions scale proportionally with urban population size. Contrary to theoretical expectations, larger cities are not more emissions efficient than smaller ones.

  7. Does size matter? Scaling of CO2 emissions and US urban areas.

    PubMed

    Fragkias, Michail; Lobo, José; Strumsky, Deborah; Seto, Karen C

    2013-01-01

    Urban areas consume more than 66% of the world's energy and generate more than 70% of global greenhouse gas emissions. With the world's population expected to reach 10 billion by 2100, nearly 90% of whom will live in urban areas, a critical question for planetary sustainability is how the size of cities affects energy use and carbon dioxide (CO2) emissions. Are larger cities more energy and emissions efficient than smaller ones? Do larger cities exhibit gains from economies of scale with regard to emissions? Here we examine the relationship between city size and CO2 emissions for U.S. metropolitan areas using a production accounting allocation of emissions. We find that for the time period of 1999-2008, CO2 emissions scale proportionally with urban population size. Contrary to theoretical expectations, larger cities are not more emissions efficient than smaller ones. PMID:23750213

  8. Soil CO2 emissions in terms of irrigation management in an agricultural soil

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Acosta, José A.; María de la Rosa, José; Faz, Ángel; Domingo, Rafael; Pérez-Pastor, Alejandro; Ángeles Muñoz, María

    2014-05-01

    Irrigation water restrictions in the Mediterranean area are reaching worrying proportions and represent a serious threat to traditional crops and encourage the movement of people who choose to work in other activities. This situation has created a growing interest in water conservation, particularly among practitioners of irrigated agriculture, the main recipient of water resources (>80%). For these and other reasons, the scientific and technical irrigation scheduling of water use to maintain and even improve harvest yield and quality has been and will remain a major challenge for irrigated agriculture. Apart from environmental and economic benefits by water savings, deficit irrigation may contribute to reduce soil CO2 emissions and enhance C sequestration in soils. The reduction of soil moisture levels decreases microbial activity, with the resulting slowing down of organic matter mineralization. Besides, the application of water by irrigation may increment the precipitation rate of carbonates, favoring the storage of C, but depending on the source of calcium or bicarbonate, the net reaction can be either storage or release of C. Thus, the objective of this study was to assess if deficit irrigation, besides contributing to water savings, can reduce soil CO2 emissions and favor the accumulation of C in soils in stable forms. The experiment was carried out along 2012 in a commercial orchard from southeast Spain cultivated with nectarine trees (Prunus persica cv. 'Viowhite'). The irrigation system was drip localized. Three irrigation treatments were assayed: a control (CT), irrigated to satisfy the total hydric needs of the crop; a first deficit irrigation (DI1), irrigated as CT except for postharvest period (16 June - 28 October) were 50% of CT was applied; and a second deficit irrigation (DI2), irrigated as DI1, except for two periods in which irrigation was suppressed (16 June-6 July and 21 July-17 August). Each treatment was setup in triplicate, randomly

  9. A constraint satisfaction method applied to the problem of controlling the CO2 emission in the Legal Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Caetano, Marco Antonio Leonel; Gherardi, Douglas Francisco Marcolino; Yoneyama, Takashi

    2013-11-01

    Socioeconomic-driven processes such as deforestation, forest degradation, forest fires, overgrazing, overharvesting of fuelwood and slash-and-burn practices constitute the primary sources of Greenhouse Gases (GHG) emissions in developing countries. Climate policies can induce the development of clean technology and offer incentives to accelerate reforestation. The Brazilian government has already acknowledged the urgency to invest in policies to reduce anthropogenic CO2 emissions in the Legal Brazilian Amazon (BA). In this work, we propose a scheme to estimate the required investments in clean technology and reforestation to achieve a prescribed short term target value for the atmospheric CO2 emission. Initially, a mathematical model is fitted to the available data to allow forecasting the values of the short term emissions of CO2 under a combination of investments in clean technology and reforestation. The investments to reduce the emissions of CO2 below a target value (400 million tons/year, starting at the initial value of 450) in 3 years’ time are proportional to the regional GDP. Using computer simulation it is possible to generate a range of possible investment values in clean technology and reforestation, so that the prescribed emission reduction is achieved without hindering economic growth. This strategy provides the necessary investment flexibility for the implementation of realistic climate policies.

  10. Allowable CO2 emissions based on regional and impact-related climate targets

    NASA Astrophysics Data System (ADS)

    Seneviratne, Sonia I.; Donat, Markus G.; Pitman, Andy J.; Knutti, Reto; Wilby, Robert L.

    2016-01-01

    Global temperature targets, such as the widely accepted limit of an increase above pre-industrial temperatures of two degrees Celsius, may fail to communicate the urgency of reducing carbon dioxide (CO2) emissions. The translation of CO2 emissions into regional- and impact-related climate targets could be more powerful because such targets are more directly aligned with individual national interests. We illustrate this approach using regional changes in extreme temperatures and precipitation. These scale robustly with global temperature across scenarios, and thus with cumulative CO2 emissions. This is particularly relevant for changes in regional extreme temperatures on land, which are much greater than changes in the associated global mean.

  11. Allowable CO2 emissions based on regional and impact-related climate targets.

    PubMed

    Seneviratne, Sonia I; Donat, Markus G; Pitman, Andy J; Knutti, Reto; Wilby, Robert L

    2016-01-28

    Global temperature targets, such as the widely accepted limit of an increase above pre-industrial temperatures of two degrees Celsius, may fail to communicate the urgency of reducing carbon dioxide (CO2) emissions. The translation of CO2 emissions into regional- and impact-related climate targets could be more powerful because such targets are more directly aligned with individual national interests. We illustrate this approach using regional changes in extreme temperatures and precipitation. These scale robustly with global temperature across scenarios, and thus with cumulative CO2 emissions. This is particularly relevant for changes in regional extreme temperatures on land, which are much greater than changes in the associated global mean.

  12. Pruning removal from orchards for energetic use: impacts on SOC and CO2-emissions

    NASA Astrophysics Data System (ADS)

    Germer, Sonja; Lanza, Giacomo; Schleicher, Sarah; Bischoff, Wolf-Anno; Gomez Palermo, Maider; Nogues, Fernando Sebastian; Kern, Jürgen

    2016-04-01

    Prunings of orchards are usually burnt or left on the soil for nutrient and organic carbon recycling. Recently the interest rose to remove prunings for energetic use. Effects of pruning removal on soil physical and chemical characteristics are expected rather in the long term. Under certain circumstances, however, soil characteristics as organic carbon content and greenhouse gas emissions might change on the short term as our literature review revealed. The main objective of this research was to determine if pruning removal from orchards changes soil organic carbon content and CO2-emission from soils in the short-term. We compared six different study sites in Spain, France and Germany in terms of impacts on soil chemistry (total and organic carbon) and four sites for impacts on CO2-emissions during 2 years. A block design was set up over two rows each with two parcels where we removed prunings and two parcels where prunings were chipped and left on the soil (n=4). As soil characteristics may vary between tree rows and interrows of orchards, we sampled both positions separately. To assess the relative contribution of CO2 emissions from carbonate and organic material, the isotopic signature of CO2 (δ 13CO_2) was analyzed for one orchard. Our results show that pruning removal could significantly decrease soil organic carbon in the tree row after 2 years of pruning removal, as found for one German orchard. No treatment effects were detected on CO2-emissions. We found, however, differences in CO2 emissions according to the sampling position in tree rows and interrows. More CO2 emission was found for that row position per orchard with higher soil organic carbon. Isotopic CO2 signature indicated that elevated CO2 emissions were rather linked to higher microbial decomposition or root respiration than to the release from carbonates. As no pruning wood decomposition effect on CO2 emissions were apparent, but soil with higher organic carbon released more CO2, it is expected

  13. Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2--The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates.

    PubMed

    Luca, Oana R; Fenwick, Aidan Q

    2015-11-01

    The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination.

  14. How Uncertain Are Estimates of CO2 Emissions

    SciTech Connect

    Marland, Gregg; Hamal, Khrystyna; Jonas, Matthias

    2009-02-01

    Can satellite or other remotely sensed data provide independent estimates - or even confirmation of existing estimates - for emissions from power plants, highways, projects, cities, countries, or groups of countries? The answer for now is no; estimates of emissions from fossil fuels are actually one of the best constrained pieces of data in analyzing the global carbon cycle.

  15. Spatial Disaggregation of CO2 Emissions for the State of California

    SciTech Connect

    de la Rue du Can, Stephane; de la Rue du Can, Stephane; Wenzel, Tom; Fischer, Marc

    2008-06-11

    This report allocates California's 2004 statewide carbon dioxide (CO2) emissions from fuel combustion to the 58 counties in the state. The total emissions are allocated to counties using several different methods, based on the availability of data for each sector. Data on natural gas use in all sectors are available by county. Fuel consumption by power and combined heat and power generation plants is available for individual plants. Bottom-up models were used to distribute statewide fuel sales-based CO2 emissions by county for on-road vehicles, aircraft, and watercraft. All other sources of CO2 emissions were allocated to counties based on surrogates for activity. CO2 emissions by sector were estimated for each county, as well as for the South Coast Air Basin. It is important to note that emissions from some sources, notably electricity generation, were allocated to counties based on where the emissions were generated, rather than where the electricity was actually consumed. In addition, several sources of CO2 emissions, such as electricity generated in and imported from other states and international marine bunker fuels, were not included in the analysis. California Air Resource Board (CARB) does not include CO2 emissions from interstate and international air travel, in the official California greenhouse gas (GHG) inventory, so those emissions were allocated to counties for informational purposes only. Los Angeles County is responsible for by far the largest CO2 emissions from combustion in the state: 83 Million metric tonnes (Mt), or 24percent of total CO2 emissions in California, more than twice that of the next county (Kern, with 38 Mt, or 11percent of statewide emissions). The South Coast Air Basin accounts for 122 MtCO2, or 35percent of all emissions from fuel combustion in the state. The distribution of emissions by sector varies considerably by county, with on-road motor vehicles dominating most counties, but large stationary sources and rail travel

  16. Tillage, mulch and N fertilizer affect emissions of CO2 under the rain fed condition.

    PubMed

    Tanveer, Sikander Khan; Wen, Xiaoxia; Lu, Xing Li; Zhang, Junli; Liao, Yuncheng

    2013-01-01

    A two year (2010-2012) study was conducted to assess the effects of different agronomic management practices on the emissions of CO2 from a field of non-irrigated wheat planted on China's Loess Plateau. Management practices included four tillage methods i.e. T1: (chisel plow tillage), T2: (zero-tillage), T3: (rotary tillage) and T4: (mold board plow tillage), 2 mulch levels i.e., M0 (no corn residue mulch) and M1 (application of corn residue mulch) and 5 levels of N fertilizer (0, 80, 160, 240, 320 kg N/ha). A factorial experiment having a strip split-split arrangement, with tillage methods in the main plots, mulch levels in the sub plots and N-fertilizer levels in the sub-sub plots with three replicates, was used for this study. The CO2 data were recorded three times per week using a portable GXH-3010E1 gas analyzer. The highest CO2 emissions were recorded following rotary tillage, compared to the lowest emissions from the zero tillage planting method. The lowest emissions were recorded at the 160 kg N/ha, fertilizer level. Higher CO2 emissions were recorded during the cropping year 2010-11 relative to the year 2011-12. During cropping year 2010-11, applications of corn residue mulch significantly increased CO2 emissions in comparison to the non-mulched treatments, and during the year 2011-12, equal emissions were recorded for both types of mulch treatments. Higher CO2 emissions were recorded immediately after the tillage operations. Different environmental factors, i.e., rain, air temperatures, soil temperatures and soil moistures, had significant effects on the CO2 emissions. We conclude that conservation tillage practices, i.e., zero tillage, the use of corn residue mulch and optimum N fertilizer use, can reduce CO2 emissions, give better yields and provide environmentally friendly options.

  17. Eddy Covariance Method for CO2 Emission Measurements: CCS Applications, Principles, Instrumentation and Software

    NASA Astrophysics Data System (ADS)

    Burba, George; Madsen, Rod; Feese, Kristin

    2013-04-01

    and technical papers. A free open-source software package with a user-friendly interface was developed accordingly for computing final fully corrected CO2 emission numbers [10]. The presentation covers highlights of the eddy covariance method, its application to geological carbon sequestration, key requirements, instrumentation and software, and reviews educational resources particularly useful for carbon sequestration research. References: [1] Aubinet, M., T. Vesala, and D. Papale (Eds.), 2012. Eddy Covariance: A Practical Guide to Measurement and Data Analysis. Springer-Verlag, 442 pp. [2] Foken T., 2008. Micrometeorology. Springer-Verlag, 308 pp. [4] Finley, R., 2009. An Assessment of Geological Carbon Sequestration in the Illinois Basin Overview of the Decatur-Illinois Basin Site. MGSC, http://www.istc.illinois.edu/info/govs_awards_docs/2009-GSA-1100-Finley.pdf [5] Liu, G. (Ed.), 2012. Greenhouse Gases: Capturing, Utilization and Reduction. Intech, 338 pp. [6] LI-COR Biosciences, 2011. Surface Monitoring for Geologic Carbon Sequestration Monitoring: Methods, Instrumentation, and Case Studies. LI-COR Biosciences, Pub. 980-11916, 15 pp. [7] Benson, S., 2006. Monitoring carbon dioxide sequestration in deep geological formations for inventory verification and carbon credits, SPE-102833, Presentation [8] Lewicki, J., G. Hilley, M. Fischer, L. Pan, C. Olden-burg, C. Dobeck, and L. Spangler, 2009.Eddy covariance observations of leakage during shallow subsurface CO2 releases. Journal of Geophys Res, 114: D12302 [9] Burba, G., 2013. Eddy Covariance Method for Scientific, Industrial, Agricultural and Regulatory Applications. LI-COR Biosciences, 328 pp. [10] LI-COR Biosciences, 2012. EddyPro 4.0: Help and User's Guide. Lincoln, NE, 208 pp.

  18. Multi-scale observations of the variability of magmatic CO2 emissions, Mammoth Mountain, CA, USA

    USGS Publications Warehouse

    Lewicki, Jennifer L.; Hilley, George E.

    2014-01-01

    One of the primary indicators of volcanic unrest at Mammoth Mountain is diffuse emission of magmatic CO2, which can effectively track this unrest if its variability in space and time and relationship to near-surface meteorological and hydrologic phenomena versus those occurring at depth beneath the mountain are understood. In June–October 2013, we conducted accumulation chamber soil CO2 flux surveys and made half-hourly CO2 flux measurements with automated eddy covariance and accumulation chamber (auto-chamber) instrumentation at the largest area of diffuse CO2 degassing on Mammoth Mountain (Horseshoe Lake tree kill; HLTK). Estimated CO2 emission rates for HLTK based on 20 June, 30 July, and 24–25 October soil CO2 flux surveys were 165, 172, and 231 t d− 1, respectively. The average (June–October) CO2 emission rate estimated for this area was 123 t d− 1 based on an inversion of 4527 eddy covariance CO2 flux measurements and corresponding modeled source weight functions. Average daily eddy covariance and auto-chamber CO2 fluxes consistently declined over the four-month observation time. Wavelet analysis of auto-chamber CO2 flux and environmental parameter time series was used to evaluate the periodicity of, and local correlation between these variables in time–frequency space. Overall, CO2 emissions at HLTK were highly dynamic, displaying short-term (hourly to weekly) temporal variability related to meteorological and hydrologic changes, as well as long-term (monthly to multi-year) variations related to migration of CO2-rich magmatic fluids beneath the volcano. Accumulation chamber soil CO2 flux surveys were also conducted in the four additional areas of diffuse CO2 degassing on Mammoth Mountain in July–August 2013. Summing CO2 emission rates for all five areas yielded a total for the mountain of 311 t d− 1, which may suggest that emissions returned to 1998–2009 levels, following an increase from 2009 to 2011.

  19. The effect of anthropogenic emissions corrections on the seasonal cycle of atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Brooks, B. J.; Hoffman, F. M.; Mills, R. T.; Erickson, D. J.; Blasing, T. J.

    2009-12-01

    A previous study (Erickson et al. 2008) approximated the monthly global emission estimates of anthropogenic CO2 by applying a 2-harmonic Fourier expansion with coefficients as a function of latitude to annual CO2 flux estimates derived from United States data (Blasing et al. 2005) that were extrapolated globally. These monthly anthropogenic CO2 flux estimates were used to model atmospheric concentrations using the NASA GEOS-4 data assimilation system. Local variability in the amplitude of the simulated CO2 seasonal cycle were found to be on the order of 2-6 ppmv. Here we used the same Fourier expansion to seasonally adjust the global annual fossil fuel CO2 emissions from the SRES A2 scenario. For a total of four simulations, both the annual and seasonalized fluxes were advected in two configurations of the NCAR Community Atmosphere Model (CAM) used in the Carbon-Land Model Intercomparison Project (C-LAMP). One configuration used the NCAR Community Land Model (CLM) coupled with the CASA‧ (carbon only) biogeochemistry model and the other used CLM coupled with the CN (coupled carbon and nitrogen cycles) biogeochemistry model. All four simulations were forced with observed sea surface temperatures and sea ice concentrations from the Hadley Centre and a prescribed transient atmospheric CO2 concentration for the radiation and land forcing over the 20th century. The model results exhibit differences in the seasonal cycle of CO2 between the seasonally corrected and uncorrected simulations. Moreover, because of differing energy and water feedbacks between the atmosphere model and the two land biogeochemistry models, features of the CO2 seasonal cycle were different between these two model configurations. This study reinforces previous findings that suggest that regional near-surface atmospheric CO2 concentrations depend strongly on the natural sources and sinks of CO2, but also on the strength of local anthropogenic CO2 emissions and geographic position. This work further

  20. Catalytic reduction of CN-, CO, and CO2 by nitrogenase cofactors in lanthanide-driven reactions.

    PubMed

    Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W

    2015-01-19

    Nitrogenase cofactors can be extracted into an organic solvent to catalyze the reduction of cyanide (CN(-)), carbon monoxide (CO), and carbon dioxide (CO2) without using adenosine triphosphate (ATP), when samarium(II) iodide (SmI2) and 2,6-lutidinium triflate (Lut-H) are employed as a reductant and a proton source, respectively. Driven by SmI2, the cofactors catalytically reduce CN(-) or CO to C1-C4 hydrocarbons, and CO2 to CO and C1-C3 hydrocarbons. The C-C coupling from CO2 indicates a unique Fischer-Tropsch-like reaction with an atypical carbonaceous substrate, whereas the catalytic turnover of CN(-), CO, and CO2 by isolated cofactors suggests the possibility to develop nitrogenase-based electrocatalysts for the production of hydrocarbons from these carbon-containing compounds.

  1. Trading Off Global Fuel Supply, CO2 Emissions and Sustainable Development.

    PubMed

    Wagner, Liam; Ross, Ian; Foster, John; Hankamer, Ben

    2016-01-01

    The United Nations Conference on Climate Change (Paris 2015) reached an international agreement to keep the rise in global average temperature 'well below 2°C' and to 'aim to limit the increase to 1.5°C'. These reductions will have to be made in the face of rising global energy demand. Here a thoroughly validated dynamic econometric model (Eq 1) is used to forecast global energy demand growth (International Energy Agency and BP), which is driven by an increase of the global population (UN), energy use per person and real GDP (World Bank and Maddison). Even relatively conservative assumptions put a severe upward pressure on forecast global energy demand and highlight three areas of concern. First, is the potential for an exponential increase of fossil fuel consumption, if renewable energy systems are not rapidly scaled up. Second, implementation of internationally mandated CO2 emission controls are forecast to place serious constraints on fossil fuel use from ~2030 onward, raising energy security implications. Third is the challenge of maintaining the international 'pro-growth' strategy being used to meet poverty alleviation targets, while reducing CO2 emissions. Our findings place global economists and environmentalists on the same side as they indicate that the scale up of CO2 neutral renewable energy systems is not only important to protect against climate change, but to enhance global energy security by reducing our dependence of fossil fuels and to provide a sustainable basis for economic development and poverty alleviation. Very hard choices will have to be made to achieve 'sustainable development' goals. PMID:26959977

  2. Trading Off Global Fuel Supply, CO2 Emissions and Sustainable Development.

    PubMed

    Wagner, Liam; Ross, Ian; Foster, John; Hankamer, Ben

    2016-01-01

    The United Nations Conference on Climate Change (Paris 2015) reached an international agreement to keep the rise in global average temperature 'well below 2°C' and to 'aim to limit the increase to 1.5°C'. These reductions will have to be made in the face of rising global energy demand. Here a thoroughly validated dynamic econometric model (Eq 1) is used to forecast global energy demand growth (International Energy Agency and BP), which is driven by an increase of the global population (UN), energy use per person and real GDP (World Bank and Maddison). Even relatively conservative assumptions put a severe upward pressure on forecast global energy demand and highlight three areas of concern. First, is the potential for an exponential increase of fossil fuel consumption, if renewable energy systems are not rapidly scaled up. Second, implementation of internationally mandated CO2 emission controls are forecast to place serious constraints on fossil fuel use from ~2030 onward, raising energy security implications. Third is the challenge of maintaining the international 'pro-growth' strategy being used to meet poverty alleviation targets, while reducing CO2 emissions. Our findings place global economists and environmentalists on the same side as they indicate that the scale up of CO2 neutral renewable energy systems is not only important to protect against climate change, but to enhance global energy security by reducing our dependence of fossil fuels and to provide a sustainable basis for economic development and poverty alleviation. Very hard choices will have to be made to achieve 'sustainable development' goals.

  3. Trading Off Global Fuel Supply, CO2 Emissions and Sustainable Development

    PubMed Central

    Wagner, Liam; Ross, Ian; Foster, John; Hankamer, Ben

    2016-01-01

    The United Nations Conference on Climate Change (Paris 2015) reached an international agreement to keep the rise in global average temperature ‘well below 2°C’ and to ‘aim to limit the increase to 1.5°C’. These reductions will have to be made in the face of rising global energy demand. Here a thoroughly validated dynamic econometric model (Eq 1) is used to forecast global energy demand growth (International Energy Agency and BP), which is driven by an increase of the global population (UN), energy use per person and real GDP (World Bank and Maddison). Even relatively conservative assumptions put a severe upward pressure on forecast global energy demand and highlight three areas of concern. First, is the potential for an exponential increase of fossil fuel consumption, if renewable energy systems are not rapidly scaled up. Second, implementation of internationally mandated CO2 emission controls are forecast to place serious constraints on fossil fuel use from ~2030 onward, raising energy security implications. Third is the challenge of maintaining the international ‘pro-growth’ strategy being used to meet poverty alleviation targets, while reducing CO2 emissions. Our findings place global economists and environmentalists on the same side as they indicate that the scale up of CO2 neutral renewable energy systems is not only important to protect against climate change, but to enhance global energy security by reducing our dependence of fossil fuels and to provide a sustainable basis for economic development and poverty alleviation. Very hard choices will have to be made to achieve ‘sustainable development’ goals. PMID:26959977

  4. Temporal Variability of Surface CO2 Emissions at the Horseshoe Lake Tree Kill, Mammoth Mountain, CA

    NASA Astrophysics Data System (ADS)

    Lewicki, J. L.; Rogie, J. D.; Hilley, G. E.; Fischer, M. L.; Tosha, T.; Aoyagi, R.; Benson, S. M.; Yamamoto, K.

    2006-12-01

    Mammoth Mountain is a dacitic volcano located on the southwestern rim of Long Valley caldera in eastern California. An eleven-month-long seismic swarm occurred beneath Mammoth in 1989 and was followed in 1990 by CO2 emissions around the flanks of the volcano, resulting in the formation of large areas of tree kill associated with high soil CO2 concentrations. Carbon dioxide emissions have persisted at Mammoth to the present day, allowing Mammoth to serve as a natural analogue for short-to-long-term CO2 leakage from geologic carbon storage sites. The Horseshoe Lake tree kill is the largest on the volcano and numerous investigations have been conducted here to quantify CO2 emission rates, determine spatial and temporal variability, and understand effects on the near-surface environment. In particular, continuous monitoring of soil CO2 fluxes (accumulation chamber method) and meteorological parameters at a point location was carried out along with repeat flux measurements along a grid in the tree-kill area in 1998-2000. Results showed large temporal variations in both point CO2 fluxes and total aerial CO2 emission rates driven primarily by fluctuations in wind and atmospheric pressure, rather than deep subsurface processes. We will build on previous studies of CO2 emissions at the Horseshoe Lake tree kill and present results of an investigation of CO2 emissions using the eddy covariance and accumulation chamber methods carried out in September-October, 2006. Spatially and temporally averaged net CO2 fluxes (eddy covariance method) will be used in conjunction with repeat point measurements of soil CO2 fluxes along a grid (accumulation chamber method) to quantify present-day CO2 emission, its temporal variability on half- hour to monthly time scales, and the physical controls on this variability. Implications of CO2 emissions at Mammoth Mountain for geologic carbon storage projects will be discussed. This work was supported in part by the Ernest Lawrence Berkeley

  5. Surface heat flow and CO2 emissions within the Ohaaki hydrothermal field, Taupo Volcanic Zone, New Zealand

    USGS Publications Warehouse

    Rissmann, C.; Christenson, B.; Werner, C.; Leybourne, M.; Cole, J.; Gravley, D.

    2012-01-01

    Carbon dioxide emissions and heat flow have been determined from the Ohaaki hydrothermal field, Taupo Volcanic Zone (TVZ), New Zealand following 20a of production (116MW e). Soil CO2 degassing was quantified with 2663 CO2 flux measurements using the accumulation chamber method, and 2563 soil temperatures were measured and converted to equivalent heat flow (Wm -2) using published soil temperature heat flow functions. Both CO2 flux and heat flow were analysed statistically and then modelled using 500 sequential Gaussian simulations. Forty subsoil CO 2 gas samples were also analysed for stable C isotopes. Following 20a of production, current CO2 emissions equated to 111??6.7T/d. Observed heat flow was 70??6.4MW, compared with a pre-production value of 122MW. This 52MW reduction in surface heat flow is due to production-induced drying up of all alkali-Cl outflows (61.5MW) and steam-heated pools (8.6MW) within the Ohaaki West thermal area (OHW). The drying up of all alkali-Cl outflows at Ohaaki means that the soil zone is now the major natural pathway of heat release from the high-temperature reservoir. On the other hand, a net gain in thermal ground heat flow of 18MW (from 25MW to 43.3??5MW) at OHW is associated with permeability increases resulting from surface unit fracturing by production-induced ground subsidence. The Ohaaki East (OHE) thermal area showed no change in distribution of shallow and deep soil temperature contours despite 20a of production, with an observed heat flow of 26.7??3MW and a CO 2 emission rate of 39??3T/d. The negligible change in the thermal status of the OHE thermal area is attributed to the low permeability of the reservoir beneath this area, which has limited production (mass extraction) and sheltered the area from the pressure decline within the main reservoir. Chemistry suggests that although alkali-Cl outflows once contributed significantly to the natural surface heat flow (~50%) they contributed little (<1%) to pre-production CO 2

  6. Ligand-based reduction of CO2 and release of CO on iron(II).

    PubMed

    Thammavongsy, Zachary; Seda, Takele; Zakharov, Lev N; Kaminsky, Werner; Gilbertson, John D

    2012-09-01

    A synthetic cycle for the CO(2)-to-CO conversion (with subsequent release of CO) based on iron(II), a redox-active pydridinediimine ligand (PDI), and an O-atom acceptor is reported. This conversion is a passive-type ligand-based reduction, where the electrons for the CO(2) conversion are supplied by the reduced PDI ligand and the ferrous state of the iron is conserved.

  7. Photogeneration of Hydride Donors and Their Use Toward CO2 Reduction

    SciTech Connect

    Fujita,E.; Muckerman, J.T.; Polyansky, D.E.

    2009-06-07

    Despite substantial effort, no one has succeeded in efficiently producing methanol from CO2 using homogeneous photocatalytic systems. We are pursuing reaction schemes based on a sequence of hydride-ion transfers to carry out stepwise reduction of CO2 to methanol. We are using hydride-ion transfer from photoproduced C-H bonds in metal complexes with bio-inspired ligands (i.e., NADH-like ligands) that are known to store one proton and two electrons.

  8. Stable Aqueous Photoelectrochemical CO2 Reduction by a Cu2 O Dark Cathode with Improved Selectivity for Carbonaceous Products.

    PubMed

    Chang, Xiaoxia; Wang, Tuo; Zhang, Peng; Wei, Yijia; Zhao, Jiubing; Gong, Jinlong

    2016-07-25

    Photocatalytic reduction of CO2 to produce fuels is a promising way to reduce CO2 emission and address the energy crisis. However, the H2 evolution reaction competes with CO2 photoreduction, which would lower the overall selectivity for carbonaceous products. Cu2 O has emerged as a promising material for suppressing the H2 evolution. However, it suffers from poor stability, which is commonly regarded as the result of the electron-induced reduction of Cu2 O. This paper describes a simple strategy using Cu2 O as a dark cathode and TiO2 as a photoanode to achieve stable aqueous CO2 reduction with a high Faradaic efficiency of 87.4 % and a selectivity of 92.6 % for carbonaceous products. We have shown that the photogenerated holes, instead of the electrons, primarily account for the instability of Cu2 O. Therefore, Cu2 O was used as a dark cathode to minimize the adverse effects of holes, by which an improved stability was achieved compared to the Cu2 O photocathode under illumination. Additionally, direct exposure of the Cu2 O surface to the electrolyte was identified as a critical factor for the high selectivity for carbonaceous products. PMID:27199242

  9. Allowable CO2 emissions based on projected changes in regional extremes and related impacts

    NASA Astrophysics Data System (ADS)

    Seneviratne, Sonia I.; Donat, Markus; Pitman, Andy; Knutti, Reto; Wilby, Robert

    2016-04-01

    Global temperature targets, such as the widely accepted 2°C and 1.5° limits, may fail to communicate the urgency of reducing CO2 emissions. Translation of CO2 emissions into regional- and impact-related climate targets could be more powerful because they resonate better with national interests. We illustrate this approach using regional changes in extreme temperatures and precipitation. These scale robustly with global temperature across scenarios, and thus with cumulative CO2 emissions. This is particularly relevant for changes in regional extreme temperatures on land, which are much greater than changes in the associated global mean. Linking cumulative CO2 emission targets to regional consequences, such as changing climate extremes, would be of particular benefit for political decision making, both in the context of climate negotiations and adaptation.

  10. Trends of anthropogenic CO2 and NO2 emissions derived from the satellite instrument SCIAMACHY

    NASA Astrophysics Data System (ADS)

    Reuter, Maximilian; Buchwitz, Michael; Hilboll, Andreas; Richter, Andreas; Schneising, Oliver; Hilker, Michael; Heymann, Jens; Bovensmann, Heinrich; Burrows, John

    2014-05-01

    Global CO2 emission inventories are currently mainly based on bottom-up estimates. These rely, e.g., on reported fossil fuel consumptions and fuel types. The associated uncertainties propagate into CO2-to-NOx emission ratios being an important measure for pollution monitoring and into biospheric carbon fluxes derived with inverse models. Co-located simultaneous SCIAMACHY satellite retrievals of XCO2 and NO2 from the years 2003-2011 are used as input for a top-down estimate of emission and emission ratio trends. In East Asia, the analysis reveals an increasing trend (4.2±0.9%/a) of the CO2-to-NOx emission ratio. This results from a large positive trend of CO2 emissions (9.8±0.7%/a) primarily driven by the growing Chinese economy exceeding the positive trend of NOx emissions (5.8±0.3%/a). The results confirm that the newly installed and renewed technology (power plants, transportation, etc.) is significantly cleaner in terms of NOx emissions. In North America and Europe negative CO2 trends balance similarly large negative NO2 trends so that no significant trends of the emission ratios are observed.

  11. Emissions of volatile organic compounds from hybrid poplar depend on CO2 concentration and genotype

    NASA Astrophysics Data System (ADS)

    Eller, A. S.; de Gouw, J. A.; Monson, R. K.

    2010-12-01

    Hybrid poplar is a fast-growing tree species that is likely to be an important source of biomass for the production of cellulose-based biofuels and may influence regional atmospheric chemistry through the emission of volatile organic compounds (VOCs). We used proton-transfer reaction mass spectrometry to measure VOC emissions from the leaves of four different hybrid poplar genotypes grown under ambient (400 ppm) and elevated (650 ppm) carbon dioxide concentration (CO2). The purpose of this experiment was to determine whether VOC emissions are different among genotypes and whether these emissions are likely to change as atmospheric CO2 rises. Methanol and isoprene made up over 90% of the VOC emissions and were strongly dependent on leaf age, with young leaves producing primarily methanol and switching to isoprene production as they matured. Monoterpene emissions were small, but tended to be higher in young leaves. Plants grown under elevated CO2 emitted smaller quantities of both methanol and isoprene, but the magnitude of the effect was dependent on genotype. Isoprene emission rates from mature leaves dropped from ~35 to ~28 nmol m-2 s-1 when plants were grown under elevated CO2. Emissions from individuals grown under ambient CO2 varied more based on genotype than those grown under elevated CO2, which means that we might expect smaller differences between genotypes in the future. Genotype and CO2 also affected how much carbon (C) individuals allocated to the production of VOCs. The emission rate of C from VOCs was 0.5 - 2% of the rate at which C was assimilated via net photosynthesis. The % C emitted was strongly related to genotype; clones from crosses between Populus deltoides and P. trichocarpa (T x D) allocated a greater % of their C to VOC emissions than clones from crosses of P. deltoids and P. nigra (D x N). Individuals from all four genotypes allocated a smaller % of their C to the emission of VOCs when they were grown under elevated CO2. These results

  12. Spatial Relationships of Sector-Specific Fossil-fuel CO2 Emissions in the United States

    SciTech Connect

    Zhou, Yuyu; Gurney, Kevin R.

    2011-07-01

    Quantification of the spatial distribution of sector-specific fossil fuel CO2 emissions provides strategic information to public and private decision-makers on climate change mitigation options and can provide critical constraints to carbon budget studies being performed at the national to urban scales. This study analyzes the spatial distribution and spatial drivers of total and sectoral fossil fuel CO2 emissions at the state and county levels in the United States. The spatial patterns of absolute versus per capita fossil fuel CO2 emissions differ substantially and these differences are sector-specific. Area-based sources such as those in the residential and commercial sectors are driven by a combination of population and surface temperature with per capita emissions largest in the northern latitudes and continental interior. Emission sources associated with large individual manufacturing or electricity producing facilities are heterogeneously distributed in both absolute and per capita metrics. The relationship between surface temperature and sectoral emissions suggests that the increased electricity consumption due to space cooling requirements under a warmer climate may outweigh the savings generated by lessened space heating. Spatial cluster analysis of fossil fuel CO2 emissions confirms that counties with high (low) CO2 emissions tend to be clustered close to other counties with high (low) CO2 emissions and some of the spatial clustering extends to multi-state spatial domains. This is particularly true for the residential and transportation sectors, suggesting that emissions mitigation policy might best be approached from the regional or multi-state perspective. Our findings underscore the potential for geographically focused, sector-specific emissions mitigation strategies and the importance of accurate spatial distribution of emitting sources when combined with atmospheric monitoring via aircraft, satellite and in situ measurements. Keywords: Fossil

  13. Comparison of soil CO2 emission in poorly and well-drained mineral soil at a small agricultural hillside scale

    NASA Astrophysics Data System (ADS)

    TETE, Emmanuel; Viaud, Valerie; Flechard, Chris; Walter, Christian

    2014-05-01

    The increase of greenhouse gases (GHG) in the atmosphere and the climate change which results from it, will have major effects in the 21th century. In agricultural landscapes and others ecosystems, soil CO2 emissions are controlled by thermal and hydrological regimes, but their relative importance seems to be dependant of soil drainage conditions. The purpose of this study was to measure and model soil CO2 emissions at the scale of a hillslope presenting a gradient of soil drainage conditions. The studied hillslope is located in the Kervidy-Naizin headwater catchment (Brittany, France, 48°00'N 2°50W) and corresponds to an agricultural field cropped in a maize / winter wheat rotation. Soil CO2 emissions were measured once per week from February 2013 to March 2014, in two locations contrasting by soil drainage condition: (1) well-drained mineral (WDM) soil classified as Cambisol in upslope position, (2) poorly-drained mineral (PDM) soil classified as Haplic Albeluvisol and which undergoes continuous or periodic saturation and reduction conditions in downslope position. The measurement sites of 9m2 were equipped for continuous measurement of soil water content (TDR probes) and soil temperature. Soil CO2 emissions were measured with the infrared gas analyzer (IRGA) Li-8100A (Li-Cor, Lincoln, USA) until now. Results showed that PDM soils were waterlogged in winter and autumn inducing a low CO2 emission (average of 1.1±0.2µmol.m-2.s-1) which was two times lower than CO2 emissions in WDM soil. A shift of soil moisture to field capacity leading to an availability of oxygen in soil in the spring and summer induced an increase of soil CO2 emissions in PDM soil with a maximum of 5.03±0.5µmol.m-2.s-1 at the end of July. In WDM soil, CO2 emissions were high at the end of spring (average of 7µmol.m-2.s-1) and decreased of 65% at the end of summer because of the drought conditions. The modeling of temporal variability of soil CO2 emission by temperature and moisture

  14. Biophysical and economic limits to negative CO2 emissions

    NASA Astrophysics Data System (ADS)

    Smith, Pete; Davis, Steven J.; Creutzig, Felix; Fuss, Sabine; Minx, Jan; Gabrielle, Benoit; Kato, Etsushi; Jackson, Robert B.; Cowie, Annette; Kriegler, Elmar; van Vuuren, Detlef P.; Rogelj, Joeri; Ciais, Philippe; Milne, Jennifer; Canadell, Josep G.; McCollum, David; Peters, Glen; Andrew, Robbie; Krey, Volker; Shrestha, Gyami; Friedlingstein, Pierre; Gasser, Thomas; Grübler, Arnulf; Heidug, Wolfgang K.; Jonas, Matthias; Jones, Chris D.; Kraxner, Florian; Littleton, Emma; Lowe, Jason; Moreira, José Roberto; Nakicenovic, Nebojsa; Obersteiner, Michael; Patwardhan, Anand; Rogner, Mathis; Rubin, Ed; Sharifi, Ayyoob; Torvanger, Asbjørn; Yamagata, Yoshiki; Edmonds, Jae; Yongsung, Cho

    2016-01-01

    To have a >50% chance of limiting warming below 2 °C, most recent scenarios from integrated assessment models (IAMs) require large-scale deployment of negative emissions technologies (NETs). These are technologies that result in the net removal of greenhouse gases from the atmosphere. We quantify potential global impacts of the different NETs on various factors (such as land, greenhouse gas emissions, water, albedo, nutrients and energy) to determine the biophysical limits to, and economic costs of, their widespread application. Resource implications vary between technologies and need to be satisfactorily addressed if NETs are to have a significant role in achieving climate goals.

  15. High-resolution emissions of CO2 from power generation in the USA

    NASA Astrophysics Data System (ADS)

    PéTron, Garielle; Tans, Pieter; Frost, Gregory; Chao, Danlei; Trainer, Michael

    2008-12-01

    Electricity generation accounts for close to 40% of the U.S. CO2 emissions from fossil fuel burning, making it the economic sector with the largest source of CO2. Since the late 1990s, the Environmental Protection Agency Clean Air Markets Division (EPA CAMD) has kept a repository of hourly CO2 emission data for most power plants in the conterminous United States. In this study, the CAMD CO2 data are used to derive a high spatiotemporal resolution CO2 emissions inventory for the electricity generation sector (inventory available on request). Data from 1998 to 2006 have been processed. This unique inventory can be used to improve the understanding of the carbon cycle at fine temporal and spatial scales. The CAMD data set provides the first quantitative estimates of the diurnal and seasonal cycles of the emissions as well as the year to year variability. Emissions peak in the summertime owing to the widespread use of air conditioning. Summertime emissions are in fact highly correlated with the daily average temperature. In conjunction with the EPA Emissions and Generation Resource Integrated Database (eGRID), we have derived high-resolution maps of CO2 emissions by fossil fuel burned (coal, gas, oil) for the year 2004. The CAMD data set also reflects regional anomalies in power generation such as the August 2003 blackout in the northeastern United States and the 2000-2001 increase in production in California. We recommend that all sectors of the economy report similar high-resolution CO2 emissions because of their great usefulness both for carbon cycle science and for greenhouse gases emissions mitigation and regulation.

  16. Determinants of CO2 emissions in ASEAN countries using energy and mining indicators

    NASA Astrophysics Data System (ADS)

    Nordin, Sayed Kushairi Sayed; Samat, Khairul Fadzli; Ismail, Siti Fatimah; Hamzah, Khairum; Halim, Bushra Abdul; Kun, Sek Siok

    2015-05-01

    Carbon dioxide (CO2) is the main greenhouse gas emitted from human activities. Industrial revolution is one of the triggers to accelerate the quantity of CO2 in the atmosphere which lead to undesirable changes in the cycle of carbon. Like China and United States which are affected by the economic development growth, the atmospheric CO2 level in ASEAN countries is expected to be higher from year to year. This study focuses on energy and mining indicators, namely alternative and nuclear energy, energy production, combustible renewables and waste, fossil fuel energy consumption and the pump price for diesel fuel that contribute to CO2 emissions. Six ASEAN countries were examined from 1970 to 2010 using panel data approach. The result shows that model of cross section-fixed effect is the most appropriate model with the value of R-squared is about 86%. Energy production and fossil fuel energy consumption are found to be significantly influenced to CO2 emissions.

  17. Atmospheric CO2 capture by algae: Negative carbon dioxide emission path.

    PubMed

    Moreira, Diana; Pires, José C M

    2016-09-01

    Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures.

  18. Diurnal tracking of anthropogenic CO2 emissions in the Los Angeles basin megacity during spring, 2010

    NASA Astrophysics Data System (ADS)

    Newman, S.; Jeong, S.; Fischer, M. L.; Xu, X.; Haman, C. L.; Lefer, B.; Alvarez, S.; Rappenglueck, B.; Kort, E. A.; Andrews, A. E.; Peischl, J.; Gurney, K. R.; Miller, C. E.; Yung, Y. L.

    2012-02-01

    Attributing observed CO2 variations to human or natural cause is critical to deducing and tracking emissions from observations. We have used in situ CO2, CO, and planetary boundary layer height (PBLH) measurements recorded during the CalNex-LA (CARB et al., 2008) ground campaign of 15 May-15 June 2010, in Pasadena, CA, to deduce the diurnally varying anthropogenic component of observed CO2 in the megacity of Los Angeles (LA). This affordable and simple technique, validated by carbon isotope observations, is shown to robustly attribute observed CO2 variation to anthropogenic or biogenic origin. During CalNex-LA, local fossil fuel combustion contributed up to ~50 % of the observed CO2 enhancement overnight, and ~100 % during midday. This suggests midday column observations over LA, such as those made by satellites relying on reflected sunlight, can be used to track anthropogenic emissions.

  19. Atmospheric CO2 capture by algae: Negative carbon dioxide emission path.

    PubMed

    Moreira, Diana; Pires, José C M

    2016-09-01

    Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures. PMID:27005790

  20. CO2 Emissions from the Los Angeles Basin During Spring of 2010 - Measurements vs. Model

    NASA Astrophysics Data System (ADS)

    Newman, S.; Jeong, S.; Fischer, M. L.; Xu, X.; Gurney, K. R.; Alvarez, S. L.; Rappenglueck, B.; Haman, C. L.; Lefer, B. L.; Miller, C. E.; Yung, Y. L.

    2011-12-01

    More than half of the world's population now lives in urban areas, contributing large fluxes of greenhouse gas to the atmosphere. Quantifying the spatiotemporal distribution of these emissions is critical for providing independent verification of future mitigation activities. We have used high precision measurements of CO2 and CO to determine the contribution of fossil fuel combustion (ffCO2 mixing ratio) to the total CO2 emissions in the Los Angeles basin during the CalNex-LA ground campaign of May-June 2010 in Pasadena. The ratio of COxs/CO2xs (the excess of each species above free tropospheric levels) varies significantly by time of day, giving a proxy for the fraction of ffCO2/CO2xs. Using an emission ratio for CO/CO2 for fossil fuel combustion of 0.011±0.002 (Wunch et al., 2009, Geophys Res Lett 36, L15810), we determined that burning of fossil fuels contributed ~50% overnight - 100% during midday of the total local contribution, resulting in ffCO2 of 13 - 23 ppm, respectively. These values compare very well with those calculated from Δ14C for measurements of two samples aggregated from 7-8 flask samples collected at 14:00 PST on alternate days during the first and second half of the CalNex-LA campaign: 17 and 24 ppm ffCO2, respectively. We then compared the measured values of ffCO2 with predictions combining a diurnally averaged version of the Vulcan 2.0 ffCO2 emission inventory (http://www.purdue.edu/eas/carbon/vulcan/index.php) and mesoscale transport computed with the Weather Research and Forecast (WRF) and Stochastic Time-Inverted Lagrangian Transport (STILT) models. To evaluate transport model uncertainty, we compared predicted and measured planetary boundary layer height (PBLH) and found WRF predictions compared favorably with ceilometer measurements made during the day at the Pasadena site. Initial comparison of the diurnal cycle of ffCO2 determined by the CO/CO2 ratios to that predicted with a temporally constant map of diurnal mean emissions shows

  1. Method for reducing CO2, CO, NOX, and SOx emissions

    DOEpatents

    Lee, James Weifu; Li, Rongfu

    2002-01-01

    Industrial combustion facilities are integrated with greenhouse gas-solidifying fertilizer production reactions so that CO.sub.2, CO, NO.sub.x, and SO.sub.x emissions can be converted prior to emission into carbonate-containing fertilizers, mainly NH.sub.4 HCO.sub.3 and/or (NH.sub.2).sub.2 CO, plus a small fraction of NH.sub.4 NO.sub.3 and (NH.sub.4).sub.2 SO.sub.4. The invention enhances sequestration of CO.sub.2 into soil and the earth subsurface, reduces N0.sub.3.sup.- contamination of surface and groundwater, and stimulates photosynthetic fixation of CO.sub.2 from the atmosphere. The method for converting CO.sub.2, CO, NO.sub.x, and SO.sub.x emissions into fertilizers includes the step of collecting these materials from the emissions of industrial combustion facilities such as fossil fuel-powered energy sources and transporting the emissions to a reactor. In the reactor, the CO.sub.2, CO, N.sub.2, SO.sub.x, and/or NO.sub.x are converted into carbonate-containing fertilizers using H.sub.2, CH.sub.4, or NH.sub.3. The carbonate-containing fertilizers are then applied to soil and green plants to (1) sequester inorganic carbon into soil and subsoil earth layers by enhanced carbonation of groundwater and the earth minerals, (2) reduce the environmental problem of NO.sub.3.sup.- runoff by substituting for ammonium nitrate fertilizer, and (3) stimulate photosynthetic fixation of CO.sub.2 from the atmosphere by the fertilization effect of the carbonate-containing fertilizers.

  2. Low-dimensional models for the estimation of anthropogenic CO2 emissions from atmospheric observations

    NASA Astrophysics Data System (ADS)

    van Bloemen Waanders, B.; Ray, J.; McKenna, S. A.; Yadav, V.; Michalak, A. M.

    2011-12-01

    The estimation of anthropogenic fossil fuel emissions using atmospheric observations of CO2 has recently attracted increasing interest due to its relevance to monitoring of CO2 mitigation treaties and programs. To date, techniques to perform large-scale inversions had primarily been developed within the context of understanding biospheric and oceanic fluxes. Such fluxes tend to vary relatively smoothly in space and time, making it possible to use multiGaussian models to parameterize and regularize such inversions, predicated on limited measurements of CO2 concentrations. However, the spatial distribution of anthropogenic emissions is non-stationary and multiscale, and therefore makes the use of multiGaussians models less suitable. Thus, a need exists to identify how anthropogenic emissions may be represented in a low-dimensional manner (i.e., with few parameters), for use in top-down estimation. Certain aspects of the spatial extent of anthropogenic emissions can be represented using easily measurable proxies such as nightlights, population density and GDP; in fact, fossil fuel inventories regularly use them to disaggregate regional emission budgets to finer spatial resolutions. However, such proxies can also be used to construct a priori models for anthropogenic emissions, which can then be updated, with data, through inverse modeling. In this presentation, we compare 3 low-dimensional parameterizations to characterize anthropogenic sources. The models are derived from images of nightlights over the continental USA, but adopt different arguments to achieve their dimensionality reduction. In the first model, we threshold nightlights and fit bivariate Gaussian kernels over clusters to represent emission sources; the emission field is modeled as a weighted sum of the kernels. The second approach models emissions as a weighted superposition of a filtered nightlight-distribution and a multiresolution defect, modeled with Haar wavelet. The nightlight-based methods

  3. LA Megacity: An Integrated Land-Atmosphere System for Urban CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Feng, S.; Lauvaux, T.; Newman, S.; Rao, P.; Patarasuk, R.; o'Keefe, D.; Huang, J.; Ahmadov, R.; Wong, C.; Song, Y.; Gurney, K. R.; Diaz Isaac, L. I.; Jeong, S.; Fischer, M. L.; Miller, C. E.; Duren, R. M.; Li, Z.; Yung, Y. L.; Sander, S. P.

    2015-12-01

    About 10% of the global population lives in the word's 20 megacities (cities with urban populations greater than 10 million people). Megacities account for approximately 20% of the global anthropogenic fossil fuel CO2 (FFCO2) emissions, and their proportion of emissions increases monotonically with the world population and urbanization. Megacities range in spatial extent from ~1000 - 10,000 km2 with complex topography and variable landscapes. We present here the first attempt at building an integrated land-atmosphere modeling system for megacity environments, developed and evaluated for urban CO2 emissions over the Los Angeles (LA) Megacity area. The Weather Research and Forecasting (WRF) - Chem model was coupled to a ~1.3-km FFCO2 emission product, "Hestia-LA", to simulate the transport of CO2 across the LA magacity. We define the optimal model resolution to represent both the spatial variability of the atmospheric dynamics and the spatial patterns from the CO2 emission distribution. In parallel, we evaluate multiple configurations of WRF with various physical schemes, using meteorological observations from the CalNex-LA campaign of May-June 2010. Our results suggest that there is no remarkable difference between the medium- (4-km) and high- (1.3-km) resolution simulations in terms of atmospheric model performance. However, the high-resolution modeled CO2 mixing ratios clearly outperform the results at medium resolution for capturing both the spatial distribution and the temporal variability of the urban CO2 signals. We compare the impact of physical representation errors and emission aggregation errors on the modeled CO2 mixing ratios across the LA megacity. Finally, we present a novel approach to evaluate the design of the current surface network over the LA megacity using the modeled spatial correlations. These results reinforce the importance of using high-resolution emission products over megacities to represent correctly the large spatial gradients in

  4. Variations in Mid-Ocean Ridge CO2 Emissions Driven By Glacial Cycles

    NASA Astrophysics Data System (ADS)

    Burley, J. M.; Katz, R. F.; Huybers, P. J.

    2014-12-01

    Glacial cycles impact continental volcanism through pressure changes associated with growth and retreat of ice sheets [e.g. Iceland - Jull, 1996]. Similarly, changes in sea level accompanying glacial cycles modulate mid-ocean ridge (MOR) volcanism by pressure changes and their influence on melt production [Crowley 2014; Lund 2011; Huybers 2009]. CO2 transport through the upper mantle is sensitive to mantle melting because CO2 partitions completely into the melt phase when present. Melt then transports CO2 to the ridge axis, where it enters the climate system. We present models of CO2 transport that investigate how sea level modulates the rate of CO2 emission from MORs. The total carbon reservoir in the mantle is circa 10^7 GtC [Dasgupta 2010], orders of magnitude more than the oceans (40,000 GtC) and atmosphere (600 GtC). Changes in the rate of CO2 emission from the solid Earth therefore have the potential to significantly affect the surface carbon system. We have developed an analytical model of CO2 transport from the depth of first silicate melting (~60km) to the ridge axis, enabling a calculation of CO2 emission rate for a generic section of MOR. The model assumes homogeneous mantle and energy-conserving melt production from a simplified 2-component mantle; CO2 is taken as a perfectly incompatible trace element. Pressure variations modulate the depth of initial silicate melting and hence the flux of CO2 into the melting regime. The model can also be applied to any species that is strongly partitioned into the melt (eg. Uranium, Thorium, Niobium, Barium, Rubidium). Results suggest that changing sea level over the past Myr could have altered the CO2 emissions from MOR by ~8%. The magnitude of variation in emissions is sensitive to the mantle permeability, the ridge spreading rate, and the rate of change of sea level. The travel time of melt through the mantle causes a delay between sea-level change and the CO2 response of the MOR. This delay is sensitive to plate

  5. Electrochemical reduction of CO2 to formate catalyzed by electroplated tin coating on copper foam

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Zhou, Jing; Lv, Weixin; Fang, Hailin; Wang, Wei

    2016-01-01

    Sn/f-Cu electrode has been prepared by electrodeposition Sn on a Cu foam substrate in aqueous plating solution, which has been used as the cathode for electrochemical reduction of carbon dioxide (CO2) in aqueous KHCO3 solution. Here, we have explored the effects of the deposition time and the electrolysis potential on the Faradaic efficiency for producing formate. The results demonstrate that maximum Faradaic efficiency of 83.5% is obtained at -1.8 V vs. Ag/AgCl when the Sn/f-Cu electrode is prepared by electrodeposition for 35 min. The Sn/f-Cu electrode exhibits excellent catalytic activity for CO2 reduction compared with the Cu foam electrode and the Sn plate electrode. The average current density and the production rate of formate for the Sn/f-Cu electrode are more than twice those for the Sn plate electrode during electrochemical reduction of CO2.

  6. Solar Light Photocatalytic CO2 Reduction: General Considerations and Selected Bench-Mark Photocatalysts

    PubMed Central

    Neaţu, Ştefan; Maciá-Agulló, Juan Antonio; Garcia, Hermenegildo

    2014-01-01

    The reduction of carbon dioxide to useful chemicals has received a great deal of attention as an alternative to the depletion of fossil resources without altering the atmospheric CO2 balance. As the chemical reduction of CO2 is energetically uphill due to its remarkable thermodynamic stability, this process requires a significant transfer of energy. Achievements in the fields of photocatalysis during the last decade sparked increased interest in the possibility of using sunlight to reduce CO2. In this review we discuss some general features associated with the photocatalytic reduction of CO2 for the production of solar fuels, with considerations to be taken into account of the photocatalyst design, of the limitations arising from the lack of visible light response of titania, of the use of co-catalysts to overcome this shortcoming, together with several strategies that have been applied to enhance the photocatalytic efficiency of CO2 reduction. The aim is not to provide an exhaustive review of the area, but to present general aspects to be considered, and then to outline which are currently the most efficient photocatalytic systems. PMID:24670477

  7. Solar light photocatalytic CO2 reduction: general considerations and selected bench-mark photocatalysts.

    PubMed

    Neațu, Stefan; Maciá-Agulló, Juan Antonio; Garcia, Hermenegildo

    2014-03-25

    The reduction of carbon dioxide to useful chemicals has received a great deal of attention as an alternative to the depletion of fossil resources without altering the atmospheric CO2 balance. As the chemical reduction of CO2 is energetically uphill due to its remarkable thermodynamic stability, this process requires a significant transfer of energy. Achievements in the fields of photocatalysis during the last decade sparked increased interest in the possibility of using sunlight to reduce CO2. In this review we discuss some general features associated with the photocatalytic reduction of CO2 for the production of solar fuels, with considerations to be taken into account of the photocatalyst design, of the limitations arising from the lack of visible light response of titania, of the use of co-catalysts to overcome this shortcoming, together with several strategies that have been applied to enhance the photocatalytic efficiency of CO2 reduction. The aim is not to provide an exhaustive review of the area, but to present general aspects to be considered, and then to outline which are currently the most efficient photocatalytic systems.

  8. Photocatalytic and photoelectrocatalytic reduction of CO2 using heterogeneous catalysts with controlled nanostructures.

    PubMed

    Xie, Shunji; Zhang, Qinghong; Liu, Guodong; Wang, Ye

    2016-01-01

    The development of efficient artificial photocatalysts and photoelectrocatalysts for the reduction of CO2 with H2O to fuels and chemicals has attracted much attention in recent years. Although the state-of-the-art for the production of fuels or chemicals from CO2 using solar energy is still far from practical consideration, rich knowledge has been accumulated to understand the key factors that determine the catalytic performances. This Feature article highlights recent advances in the photocatalytic and photoelectrocatalytic reduction of CO2 with H2O using heterogeneous semiconductor-based catalysts. The effects of structural aspects of semiconductors, such as crystalline phases, particle sizes, morphologies, exposed facets and heterojunctions, on their catalytic behaviours are discussed. The roles of different types of cocatalysts and the impact of their nanostructures on surface CO2 chemisorption and reduction are also analysed. The present article aims to provide insights into the rational design of efficient heterogeneous catalysts with controlled nanostructures for the photocatalytic and photoelectrocatalytic reduction of CO2 with H2O.

  9. Frozen cropland soil in northeast China as source of N2O and CO2 emissions.

    PubMed

    Miao, Shujie; Qiao, Yunfa; Han, Xiaozeng; Brancher Franco, Roberta; Burger, Martin

    2014-01-01

    Agricultural soils are important sources of atmospheric N2O and CO2. However, in boreal agro-ecosystems the contribution of the winter season to annual emissions of these gases has rarely been determined. In this study, soil N2O and CO2 fluxes were measured for 6 years in a corn-soybean-wheat rotation in northeast China to quantify the contribution of wintertime N2O and CO2 fluxes to annual emissions. The treatments were chemical fertilizer (NPK), chemical fertilizer plus composted pig manure (NPKOM), and control (Cont.). Mean soil N2O fluxes among all three treatments in the winter (November-March), when soil temperatures are below -7°C for extended periods, were 0.89-3.01 µg N m(-2) h(-1), and in between the growing season and winter (October and April), when freeze-thaw events occur, 1.73-5.48 µg N m(-2) h(-1). The cumulative N2O emissions were on average 0.27-1.39, 0.03-0.08 and 0.03-0.11 kg N2O_N ha(-1) during the growing season, October and April, and winter, respectively. The average contributions of winter N2O efflux to annual emissions were 6.3-12.1%. In all three seasons, the highest N2O emissions occurred in NPKOM, while NPK and Cont. emissions were similar. Cumulative CO2 emissions were 2.73-4.94, 0.13-0.20 and 0.07-0.11 Mg CO2-C ha(-1) during growing season, October and April, and winter, respectively. The contribution of winter CO2 to total annual emissions was 2.0-2.4%. Our results indicate that in boreal agricultural systems in northeast China, CO2 and N2O emissions continue throughout the winter. PMID:25536036

  10. Soil organic carbon dust emission: an omitted global source of atmospheric CO2.

    PubMed

    Chappell, Adrian; Webb, Nicholas P; Butler, Harry J; Strong, Craig L; McTainsh, Grant H; Leys, John F; Viscarra Rossel, Raphael A

    2013-10-01

    Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks.

  11. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data

    NASA Astrophysics Data System (ADS)

    Ogle, Stephen M.; Davis, Kenneth; Lauvaux, Thomas; Schuh, Andrew; Cooley, Dan; West, Tristram O.; Heath, Linda S.; Miles, Natasha L.; Richardson, Scott; Breidt, F. Jay; Smith, James E.; McCarty, Jessica L.; Gurney, Kevin R.; Tans, Pieter; Denning, A. Scott

    2015-03-01

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country’s contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated emissions associated with managing lands for carbon sequestration and other activities, which often have large uncertainties. We report here on the challenges and results associated with a case study using atmospheric measurements of CO2 concentrations and inverse modeling to verify nationally-reported biogenic CO2 emissions. The biogenic CO2 emissions inventory was compiled for the Mid-Continent region of United States based on methods and data used by the US government for reporting to the UNFCCC, along with additional sources and sinks to produce a full carbon balance. The biogenic emissions inventory produced an estimated flux of -408 ± 136 Tg CO2 for the entire study region, which was not statistically different from the biogenic flux of -478 ± 146 Tg CO2 that was estimated using the atmospheric CO2 concentration data. At sub-regional scales, the spatial density of atmospheric observations did not appear sufficient to verify emissions in general. However, a difference between the inventory and inversion results was found in one isolated area of West-central Wisconsin. This part of the region is dominated by forestlands, suggesting that further investigation may be warranted into the forest C stock or harvested wood product data from this portion of the study area. The results suggest that observations of atmospheric CO2 concentration data and inverse modeling could be used to verify biogenic emissions, and provide more confidence in biogenic GHG emissions reporting to the UNFCCC.

  12. Soil organic carbon dust emission: an omitted global source of atmospheric CO2.

    PubMed

    Chappell, Adrian; Webb, Nicholas P; Butler, Harry J; Strong, Craig L; McTainsh, Grant H; Leys, John F; Viscarra Rossel, Raphael A

    2013-10-01

    Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks. PMID:23897802

  13. The contribution of aquatic metabolism to CO2 emissions from New Hampshire streams

    NASA Astrophysics Data System (ADS)

    Koenig, L.; Snyder, L. E.; McDowell, W. H.; Hunt, C. W.

    2015-12-01

    Fluvial networks represent a significant source of carbon dioxide (CO2) to the atmosphere. Recent evidence has highlighted the ubiquity of CO2 supersaturation in streams, rivers, and lakes worldwide, yet our understanding of how the source of this CO2 flux (e.g. in situ aquatic production versus soil and groundwater sources within the catchment) varies in time and across different aquatic systems remains limited. In this study we used continuous, high-frequency measurements of dissolved oxygen (DO) and CO2 to model stream metabolism and CO2 emissions for five stream sites across New Hampshire that vary in size, nutrient loading, and landscape context, with the goal of quantitatively partitioning the aquatic CO2 flux into catchment and aquatic sources, respectively. Spectral analysis of the DO and CO2 time series indicates that these gases often deviated from the pure inverse behavior that would be expected if CO2 flux originated solely from in-stream biological activity. Across all streams, the estimated contribution of aquatic net ecosystem production (NEP) to stream CO2 flux varied from approximately 0% to 50%. For each site, the proportion of CO2 flux supported by aquatic NEP was lower at higher discharge, perhaps due to increased CO2 transport from soils to streams during wetter periods, and/or due to effects of scouring flows and carbon removal on stream metabolism. Our data provides evidence that catchment sources represent substantial contributions to aquatic CO2 flux across temperate streams, but that the proportion of CO2 flux originating from net in situ production and carbon transformation is variable throughout the growing season.

  14. Regulated deficit irrigation can decrease soil CO2 emissions in fruit orchards

    NASA Astrophysics Data System (ADS)

    Zornoza, Raul; Acosta, José Alberto; Martínez-Martínez, Silvia; De la Rosa, Jose M.°; Faz, Angel; Pérez-Pastor, Alejandro

    2016-04-01

    Irrigation water restrictions in the Mediterranean area have created a growing interest in water conservation. Apart from environmental and economic benefits by water savings, regulated deficit irrigation (RDI) may contribute to reduce soil CO2 emissions and enhance C sequestration in soils, by decreasing microbial and root activity in response to decreased soil moisture levels. An experiment was established in four orchards (peach, apricot, Saturn peach and grape) to investigate the effects of regulated deficit irrigation (RDI) on soil CO2 emissions. Two irrigation treatments were assayed: full irrigation (FI), and RDI, irrigated as FI except for postharvest period (peach, apricot, Saturn peach) or post-veraison period (grape) were 50% of FI was applied. The application of deficit caused a significant decrease in CO2 emission rates, with rates in average of 90 mg CO2-C m-2 h-1, 120 mg CO2-C m-2 h-1, 60 mg CO2-C m-2 h-1 and 60 mg CO2-C m-2 h-1 lower than FI during the period when deficit was applied for peach, apricot, Saturn peach and grape. This confirms the high effectiveness of the RDI strategies not only to save water consumption but also to decrease soil CO2 emissions. However, monitoring during longer periods is needed to verify that this trend is long-term maintained, and assess if soil carbon stocks are increase or most CO2 emissions derive from root respiration. Acknowledgements This work has been funded by the European Union LIFE+ project IRRIMAN (LIFE13 ENV/ES/000539).

  15. Enhanced electrocatalytic CO2 reduction via field-induced reagent concentration

    NASA Astrophysics Data System (ADS)

    Liu, Min; Pang, Yuanjie; Zhang, Bo; de Luna, Phil; Voznyy, Oleksandr; Xu, Jixian; Zheng, Xueli; Dinh, Cao Thang; Fan, Fengjia; Cao, Changhong; de Arquer, F. Pelayo García; Safaei, Tina Saberi; Mepham, Adam; Klinkova, Anna; Kumacheva, Eugenia; Filleter, Tobin; Sinton, David; Kelley, Shana O.; Sargent, Edward H.

    2016-09-01

    Electrochemical reduction of carbon dioxide (CO2) to carbon monoxide (CO) is the first step in the synthesis of more complex carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the reaction suffers from slow kinetics owing to the low local concentration of CO2 surrounding typical CO2 reduction reaction catalysts. Alkali metal cations are known to overcome this limitation through non-covalent interactions with adsorbed reagent species, but the effect is restricted by the solubility of relevant salts. Large applied electrode potentials can also enhance CO2 adsorption, but this comes at the cost of increased hydrogen (H2) evolution. Here we report that nanostructured electrodes produce, at low applied overpotentials, local high electric fields that concentrate electrolyte cations, which in turn leads to a high local concentration of CO2 close to the active CO2 reduction reaction surface. Simulations reveal tenfold higher electric fields associated with metallic nanometre-sized tips compared to quasi-planar electrode regions, and measurements using gold nanoneedles confirm a field-induced reagent concentration that enables the CO2 reduction reaction to proceed with a geometric current density for CO of 22 milliamperes per square centimetre at -0.35 volts (overpotential of 0.24 volts). This performance surpasses by an order of magnitude the performance of the best gold nanorods, nanoparticles and oxide-derived noble metal catalysts. Similarly designed palladium nanoneedle electrocatalysts produce formate with a Faradaic efficiency of more than 90 per cent and an unprecedented geometric current density for formate of 10 milliamperes per square centimetre at -0.2 volts, demonstrating the wider applicability of the field-induced reagent concentration concept.

  16. Highly Dense Cu Nanowires for Low-Overpotential CO2 Reduction.

    PubMed

    Raciti, David; Livi, Kenneth J; Wang, Chao

    2015-10-14

    Electrochemical reduction of CO2, an artificial way of carbon recycling, represents one promising solution for energy and environmental sustainability. However, it is challenged by the lack of active and selective catalysts. Here, we report a two-step synthesis of highly dense Cu nanowires as advanced electrocatalysts for CO2 reduction. CuO nanowires were first grown by oxidation of Cu mesh in air and then reduced by either annealing in the presence of hydrogen or applying a cathodic electrochemical potential to produce Cu nanowires. The two reduction methods generated Cu nanowires with similar dimensions but distinct surface structures, which have provided an ideal platform for comparative studies of the effect of surface structure on the electrocatalytic properties. In particular, the Cu nanowires generated by electrochemical reduction were highly active and selective for CO2 reduction, requiring an overpotential of only 0.3 V to reach 1 mA/cm(2) electrode current density and achieving Faradaic efficiency toward CO as high as ∼60%. Our work has advanced the understanding of the structure-property relationship of Cu-based nanocatalysts, which could be valuable for the further development of advanced electrocatalytic materials for CO2 reduction.

  17. Impact of warming on CO2 emissions from streams countered by aquatic photosynthesis

    NASA Astrophysics Data System (ADS)

    Demars, Benoît O. L.; Gíslason, Gísli M.; Ólafsson, Jón S.; Manson, J. Russell; Friberg, Nikolai; Hood, James M.; Thompson, Joshua J. D.; Freitag, Thomas E.

    2016-10-01

    Streams and rivers are an important source of CO2 emissions. One important control of these emissions is the metabolic balance between photosynthesis, which converts CO2 to organic carbon, and respiration, which converts organic carbon into CO2 (refs ,). Carbon emissions from rivers could increase with warming, independently of organic carbon inputs, because the apparent activation energy is predicted to be higher for respiration than photosynthesis. However, physiological CO2-concentrating mechanisms may prevent the increase in photorespiration, limiting photosynthesis with warming. Here we report the thermal response of aquatic photosynthesis from streams located in geothermal areas of North America, Iceland and Kamchatka with water temperatures ranging between 4 and 70 °C. Based on a thermodynamic theory of enzyme kinetics, we show that the apparent activation energy of aquatic ecosystem photosynthesis is approximately 0.57 electron volts (eV) for temperatures ranging from 4 to 45 °C, which is similar to that of respiration. This result and a global synthesis of 222 streams suggest that warming will not create increased stream and river CO2 emissions from a warming-induced imbalance between photosynthesis and respiration. However, temperature could affect annual CO2 emissions from streams if ecosystem respiration is independent of gross primary production, and may be amplified by increasing organic carbon supply.

  18. Status of Geological Storage of CO2 as Part of Negative Emissions Strategy

    NASA Astrophysics Data System (ADS)

    Benson, S. M.

    2014-12-01

    Recent analyses show that many GHG stabilization scenarios require technologies that permanently extract CO2 from the atmosphere -so-called "net negative emissions." Among the most promising negative emissions approaches is bioenergy with carbon capture and storage (BECCS). The most mature options for CO2 storage are in sedimentary rocks located in thick sedimentary basins. Within those basins, CO2 can be stored either in depleted or depleting hydrocarbon formations or in so-called saline aquifers. In addition to the economic costs of bioenergy with CO2 capture, key to the success of and scale at which BECCS can contribute to negative emissions is the ability to store quantities on the order of 1 Gt per year of CO2. Today, about 65 Mt of CO2 per year are injected underground for the purposes of enhancing oil recovery (CO2-EOR) or for CO2 storage, the vast majority being for CO2-EOR. Achieving 1 Gt per year of negative emissions will require a 15-fold scale up of the current injection operations. This paper will review the conditions necessary for storage at this scale, identify what has been learned from nearly 2 decades of experience with CO2 storage that provides insight into the feasibility of CO2 storage on this scale, and identify critical issues that remain to be resolved to meet these ambitious negative emissions targets. Critical technological issues include but are not limited to: the amount of CO2 storage capacity that is available and where it is located in relation to biomass energy resources; identification of sustainable injection rates and how this depends on the properties of the geological formation; the extent to which water extraction will be required to manage the magnitude of pressure buildup; identification of regions at high risk for induced seismicity that could damage structures and infrastructure; and selection of sites with a adequate seals to permanently contain CO2. Social, economic and political issues are also important: including the

  19. Regional estimates of the transient climate response to cumulative CO2 emissions

    NASA Astrophysics Data System (ADS)

    Leduc, Martin; Matthews, H. Damon; de Elía, Ramón

    2016-05-01

    The Transient Climate Response to cumulative carbon Emissions (TCRE) measures the response of global temperatures to cumulative CO2 emissions. Although the TCRE is a global quantity, climate impacts manifest predominantly in response to local climate changes. Here we quantify the link between CO2 emissions and regional temperature change, showing that regional temperatures also respond approximately linearly to cumulative CO2 emissions. Using an ensemble of twelve Earth system models, we present a novel application of pattern scaling to define the regional pattern of temperature change per emission of CO2. Ensemble mean regional TCRE values range from less than 1 °C per TtC for some ocean regions, to more than 5 °C per TtC in the Arctic, with a pattern of higher values over land and at high northern latitudes. We find also that high-latitude ocean regions deviate more strongly from linearity as compared to land and lower-latitude oceans. This suggests that ice-albedo and ocean circulation feedbacks are important contributors to the overall negative deviation from linearity of the global temperature response to high levels of cumulative emissions. The strong linearity of the regional climate response over most land regions provides a robust way to quantitatively link anthropogenic CO2 emissions to local-scale climate impacts.

  20. Tree-ring 14C and CO2 emissions at Mammoth Mountain and Yellowstone, USA

    NASA Astrophysics Data System (ADS)

    Bergfeld, D.; McGeehin, J. P.; King, J.; Heasler, H.; Evans, W. C.

    2010-12-01

    A large pulse of magmatic CO2 began venting through soils on the flanks of Mammoth Mountain CA within months of a local seismic swarm in 1989. Previous workers have shown that the CO2 efflux rate was large enough to kill ~0.5 km2 of forest and cause substantial depletion of 14C in the wood of surviving trees at the edges of the kill zones. CO2 efflux at Mammoth Mountain continues to be well-studied, in part because of the obvious link between the seismic swarm and the onset of outgassing. A somewhat similar event apparently occurred a decade previously in the Yellowstone caldera, where we see a record of 14C depletion of 10-25% in a tree at Cooking Hillside in the Mud Volcano area. The 14C levels in tree core data show that CO2 emissions began to increase during a local seismic swarm in 1978. A huge drop in 14C in the 1979 growth ring suggests that CO2 emissions increased about 5-fold over values earlier in the decade. The emissions spike persisted into 1980 but at greatly reduced levels. This event at Mud Volcano occurred in a thermal area long known to emit CO2 gas and was associated with a substantial increase in surface heating and steam emission, in contrast to the case of Mammoth Mountain. However, the two events share some important similarities: increased CO2 emissions began within months of the onset of shallow (<7 km) seismic swarms, emissions peaked within 1-2 years later, and peak emissions are estimated at ~1000 tonnes of CO2 per day. Seismicity in both cases was likely driven by CO2-rich hydrous fluids; intrusion of magma into the shallow crust seems unlikely, particularly at Yellowstone where the youngest intra-caldera lavas are 70 ka. These similarities imply that, while each event has unique attributes, both are more likely variants on a process that may be fairly common in areas of magmatism. Additional tree coring at Mammoth Mountain will allow a direct comparison between 14C depletion and annual CO2 flux surveys. Ongoing tree-core 14C studies at

  1. Reducing energy-related CO2 emissions using accelerated weathering of limestone

    USGS Publications Warehouse

    Rau, G.H.; Knauss, K.G.; Langer, W.H.; Caldeira, K.

    2007-01-01

    The use and impacts of accelerated weathering of limestone (AWL; reaction: CO2+H2O+CaCO3???Ca2++2(HCO3-) is explored as a CO2 capture and sequestration method. It is shown that significant limestone resources are relatively close to a majority of CO2-emitting power plants along the coastal US, a favored siting location for AWL. Waste fines, representing more than 20% of current US crushed limestone production (>109 tonnes/yr), could provide an inexpensive or free source of AWL carbonate. With limestone transportation then as the dominant cost variable, CO2 mitigation costs of $3-$4/tonne appear to be possible in certain locations. Perhaps 10-20% of US point-source CO2 emissions could be mitigated in this fashion. It is experimentally shown that CO2 sequestration rates of 10-6 to 10-5 moles/sec per m2 of limestone surface area are achievable, with reaction densities on the order of 10-2 tonnes CO2 m-3day-1, highly dependent on limestone particle size, solution turbulence and flow, and CO2 concentration. Modeling shows that AWL would allow carbon storage in the ocean with significantly reduced impacts to seawater pH relative to direct CO2 disposal into the atmosphere or sea. The addition of AWL-derived alkalinity to the ocean may itself be beneficial for marine biota. ?? 2006 Elsevier Ltd. All rights reserved.

  2. Inversions of CO2 Emissions from the Paris Area Using Yearlong Measurement Series

    NASA Astrophysics Data System (ADS)

    Staufer, J.; Broquet, G.; Bréon, F. M.; Puygrenier, V.; Xueref-Remy, I.; Ramonet, M.; Perrussel, O.; Chevallier, F.; Dieudonné, E.; Lopez, M.; Schmidt, M.; Ciais, P.

    2014-12-01

    Estimates of fossil fuel CO2 emission from urban areas rely on inventories that are based upon energy-use consumption for different fuel types, various socio-economic activity data and emission factors. There is growing interest in improving those estimates by using an atmospheric inversion approach based on transport modeling and CO2 measurements. Bréon et al. (ACPD, 2014) have recently developed a Bayesian inversion framework to control the daily CO2 fluxes of the Paris urban area during a 2 months period. The inversion framework relies on the transport model CHIMERE with a 2 km spatial resolution and uses atmospheric CO2 concentrations measurements obtained from three monitoring stations at the edge of the Paris urban area, installed as part of the CO2-MEGAPARIS and ICOS-France projects. The method relies on the measured daytime CO2 gradients between up- and downwind stations to correct the prior 6-hour mean emissions of the Paris area, given by the AIRPARIF regional air quality monitoring agency. The system, however, relies on the spatial distribution of the AIRPARIF inventory and does not attempt at correcting it. Here, we apply the inversion framework to one year of atmospheric CO2 observations (August 2010 - July 2011). We show that the results for the monthly budgets exhibit a reasonable seasonal cycle. We check that the sensitivity to the prior estimates of the monthly budgets and to the meteorological forcing to CHIMERE is low, which demonstrates that the system is strongly controlled by observations.

  3. Rational Design of a Hierarchical Tin Dendrite Electrode for Efficient Electrochemical Reduction of CO2.

    PubMed

    Won, Da Hye; Choi, Chang Hyuck; Chung, Jaehoon; Chung, Min Wook; Kim, Eun-Hee; Woo, Seong Ihl

    2015-09-21

    Catalysis is a key technology for the synthesis of renewable fuels through electrochemical reduction of CO2 . However, successful CO2 reduction still suffers from the lack of affordable catalyst design and understanding the factors governing catalysis. Herein, we demonstrate that the CO2 conversion selectivity on Sn (or SnOx /Sn) electrodes is correlated to the native oxygen content at the subsurface. Electrochemical analyses show that the reduced Sn electrode with abundant oxygen species effectively stabilizes a CO2 (.-) intermediate rather than the clean Sn surface, and consequently results in enhanced formate production in the CO2 reduction. Based on this design strategy, a hierarchical Sn dendrite electrode with high oxygen content, consisting of a multi-branched conifer-like structure with an enlarged surface area, was synthesized. The electrode exhibits a superior formate production rate (228.6 μmol h(-1)  cm(-2) ) at -1.36 VRHE without any considerable catalytic degradation over 18 h of operation. PMID:26219092

  4. Rational Design of a Hierarchical Tin Dendrite Electrode for Efficient Electrochemical Reduction of CO2.

    PubMed

    Won, Da Hye; Choi, Chang Hyuck; Chung, Jaehoon; Chung, Min Wook; Kim, Eun-Hee; Woo, Seong Ihl

    2015-09-21

    Catalysis is a key technology for the synthesis of renewable fuels through electrochemical reduction of CO2 . However, successful CO2 reduction still suffers from the lack of affordable catalyst design and understanding the factors governing catalysis. Herein, we demonstrate that the CO2 conversion selectivity on Sn (or SnOx /Sn) electrodes is correlated to the native oxygen content at the subsurface. Electrochemical analyses show that the reduced Sn electrode with abundant oxygen species effectively stabilizes a CO2 (.-) intermediate rather than the clean Sn surface, and consequently results in enhanced formate production in the CO2 reduction. Based on this design strategy, a hierarchical Sn dendrite electrode with high oxygen content, consisting of a multi-branched conifer-like structure with an enlarged surface area, was synthesized. The electrode exhibits a superior formate production rate (228.6 μmol h(-1)  cm(-2) ) at -1.36 VRHE without any considerable catalytic degradation over 18 h of operation.

  5. Electrochemical Reduction of CO2 at Metal Electrodes in a Distillable Ionic Liquid.

    PubMed

    Chen, Lu; Guo, Si-Xuan; Li, Fengwang; Bentley, Cameron; Horne, Mike; Bond, Alan M; Zhang, Jie

    2016-06-01

    The electroreduction of CO2 in the distillable ionic liquid dimethylammonium dimethylcarbamate (dimcarb) has been investigated with 17 metal electrodes. Analysis of the electrolysis products reveals that aluminum, bismuth, lead, copper, nickel, palladium, platinum, iron, molybdenum, titanium and zirconium electroreduce the available protons in dimcarb to hydrogen rather than reducing CO2 . Conversely, indium, tin, zinc, silver and gold are able to catalyze the reduction of CO2 to predominantly carbon monoxide (CO) and to a lesser extent, formate ([HCOO](-) ). In all cases, the applied potential was found to have a minimal influence on the distribution of the reduction products. Overall, indium was found to be the best electrocatalyst for CO2 reduction in dimcarb, with faradaic efficiencies of approximately 45 % and 40 % for the generation of CO and [HCOO](-) , respectively, at a potential of -1.34 V versus Cc(+/0) (Cc(+) =cobaltocenium) employing a dimethylamine to CO2 ratio of less than 1.8:1. PMID:27164263

  6. Size-dependent electrocatalytic reduction of CO2 over Pd nanoparticles.

    PubMed

    Gao, Dunfeng; Zhou, Hu; Wang, Jing; Miao, Shu; Yang, Fan; Wang, Guoxiong; Wang, Jianguo; Bao, Xinhe

    2015-04-01

    Size effect has been regularly utilized to tune the catalytic activity and selectivity of metal nanoparticles (NPs). Yet, there is a lack of understanding of the size effect in the electrocatalytic reduction of CO2, an important reaction that couples with intermittent renewable energy storage and carbon cycle utilization. We report here a prominent size-dependent activity/selectivity in the electrocatalytic reduction of CO2 over differently sized Pd NPs, ranging from 2.4 to 10.3 nm. The Faradaic efficiency for CO production varies from 5.8% at -0.89 V (vs reversible hydrogen electrode) over 10.3 nm NPs to 91.2% over 3.7 nm NPs, along with an 18.4-fold increase in current density. Based on the Gibbs free energy diagrams from density functional theory calculations, the adsorption of CO2 and the formation of key reaction intermediate COOH* are much easier on edge and corner sites than on terrace sites of Pd NPs. In contrast, the formation of H* for competitive hydrogen evolution reaction is similar on all three sites. A volcano-like curve of the turnover frequency for CO production within the size range suggests that CO2 adsorption, COOH* formation, and CO* removal during CO2 reduction can be tuned by varying the size of Pd NPs due to the changing ratio of corner, edge, and terrace sites.

  7. Historical changes in carbon dioxide (CO2) and dimethyl sulphide (DMS) emissions in the eutrophied Southern North Sea

    NASA Astrophysics Data System (ADS)

    Gypens, N.; Borges, A. V.; Lancelot, C.

    2012-04-01

    Anthropogenic activities after the Second World War have severely increased river nutrient [nitrogen (N) and phosphorus (P)] loads to European coastal areas. The resulting N: P: Si imbalance (compared to phytoplankton requirements) stimulated in the Southern North Sea the growth of Phaeocystis colonies modifying the functioning of the ecosystem and, therefore, the carbon but also the biogenic sulphur cycles. Phaeocystis is a significant producer of DMSP (dimethylsulphide propionate), the precursor of DMS. When emitted to the atmosphere the DMS has a cooling effect on the climate contrarily to the CO2 greenhouse gas. Since the late 1990's specific nutrient reduction policies have however considerably reduced P loads while N is maintained. In this application we explore, with a mathematical tool, the effects of changing N and P loads on air-sea CO2 exchanges and DMS marine emissions. The chosen model is the MIRO-CO2-DMS, a complex biogeochemical model describing carbon, biogenic sulphur and nutrient cycles in the marine domain. Model simulations are performed for the contemporary period since 1950, using real forcing fields for sea surface temperature, wind speed and atmospheric CO2 and RIVERSTRAHLER model simulations for river carbon and nutrient loads. Results are discussing the importance of human activities and river inputs of carbon and nutrients on the eutrophication of coastal areas, their ability to absorb atmospheric CO2 and the importance of DMS emissions associated with phytoplankton blooms, especially Phaeocystis.

  8. A Climactic Feedback? Variations in Mid-Ocean Ridge CO2 Emissions Driven by Glacial Cycles

    NASA Astrophysics Data System (ADS)

    Burley, J. M.; Katz, R. F.; Huybers, P. J.

    2015-12-01

    Changes in sea level associated with glacial cycles affect the pressure beneath a mid-ocean ridge (MOR) [1,2,3]. Pressure controls the depth of first melting, and therefore the rate of change of pressure controls the rate of change of the depth of first melting. The changing depth of first melting alters the effective rate at which mantle, and thus CO2, enters the melting region. Melt then transports CO2 to the ridge axis, where it enters the climate system. We calculate that the lag between sea level change and consequent variation in MOR CO2 emissions is 40-120 kyrs[4], similar to the timescale of glacial cycles. Could these variations in MOR CO2 emissions feed back on climate and lead to ice-age pacing at a small multiple of the obliquity period? [5]To test this hypothesis we begin with a climate model comprised of a global energy balance and a 1D ice sheet. The ice sheet flows under its own weight, accumulates due to precipitation, and melts in response to the local energy balance[6]. This model broadly replicates Early Pleistocene 40 kyr glacial cycles. We extend the model to include a variable greenhouse effect, according to atmospheric CO2, and variable MOR CO2 emissions driven by sea level. The lag between sea level change and MOR CO2 emissions is controlled by mantle permeability. If this model does not demonstrate MOR CO2 emissions altering glacial cycles, it would suggest this hypothesised feedback mechanism can be rejected. References[1] Huybers & Langmuir 2009; 10.1016/j.epsl.2009.07.014[2] Lund & Asimow 2011; 10.1029/2011GC003693[3] Crowley et al 2015; 10.1126/science.1261508[4] Burley & Katz 2015; 10.1016/j.epsl.2015.06.031[5] Huybers (in prep.)[6] Huybers & Tziperman 2008; 10.1029/2007PA001463

  9. Influence of Fossil Fuel Emissions on CO2 Flux Estimation by Atmospheric Inversions

    NASA Astrophysics Data System (ADS)

    Saeki, T.; Patra, P. K.; van der Laan-Luijkx, I. T.; Peters, W.

    2015-12-01

    Top-down approaches (or atmospheric inversions) using atmospheric transport models with CO2 observations are an effective way to estimate carbon fluxes at global and regional scales. CO2 flux estimation by Bayesian inversions require a priori knowledge of terrestrial biosphere and oceanic fluxes and fossil fuel (FF) CO2 emissions. In most inversion frameworks, FF CO2 is assumed to be a known quantity because FF CO2 based on world statistics are thought to be more reliable than natural CO2 fluxes. However different databases of FF CO2 emissions may have different temporal and spatial variations especially at locations where statistics are not so accurate. In this study, we use 3 datasets of fossil fuel emissions in inversion estimations and evaluate the sensitivity of the optimized CO2 fluxes to FF emissions with two different inverse models, JAMSTEC's ACTM and CarbonTracker Europe (CTE). Interannually varying a priori FF CO2 emissions were based on 1) CDIAC database, 2) EDGARv4.2 database, and 3) IEA database, with some modifications. Biosphere and oceanic fluxes were optimized. Except for FF emissions, other conditions were kept the same in our inverse experiments. The three a priori FF emissions showed ~5% (~0.3GtC/yr) differences in their global total emissions in the early 2000's and the differences reached ~9% (~0.9 GtC/yr) in 2010. This resulted in 0.5-1 GtC/yr (2001-2011) and 0.3-0.6 GtC/yr (2007-2011) differences in the estimated global total emissions for the ACTM and CTE inversions, respectively. Regional differences in the FF emissions were relatively large in East Asia (~0.5 GtC/yr for ACTM and ~0.3 GtC/yr for CTE) and Europe (~0.3 GtC/yr for ACTM). These a priori flux differences caused differences in the estimated biosphere fluxes for ACTM in East Asia and Europe and also their neighboring regions such as West Asia, Boreal Eurasia, and North Africa. The main differences in the biosphere fluxes for CTE were found in Asia and the Americas.

  10. Emissions reductions strategies

    SciTech Connect

    Sirois, R.H.

    1996-12-31

    This paper consists of the series of viewgraphs used by the author during his presentation. They tabulate nitrogen oxide reduction techniques, technical evaluation of NOx control techniques, critical system design parameters for SNCR processes, major concerns for SCR retrofit applications, integrating technologies, sulfur dioxide control for a coal fired power plant, heavy metals on US EPA`s HAPs list, and mercury emissions. Other slides show flow charts of some of these processes, as well as diagrams of equipment.

  11. Can satellite-based monitoring techniques be used to quantify volcanic CO2 emissions?

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Carn, Simon A.; Kuze, Akihiko; Kataoka, Fumie; Shiomi, Kei; Goto, Naoki; Popp, Christoph; Ajiro, Masataka; Suto, Hiroshi; Takeda, Toru; Kanekon, Sayaka; Sealing, Christine; Flower, Verity

    2014-05-01

    Since 2010, we investigate and improve possible methods to regularly target volcanic centers from space in order to detect volcanic carbon dioxide (CO2) point source anomalies, using the Japanese Greenhouse gas Observing SATellite (GOSAT). Our long-term goals are: (a) better spatial and temporal coverage of volcano monitoring techniques; (b) improvement of the currently highly uncertain global CO2 emission inventory for volcanoes, and (c) use of volcanic CO2 emissions for high altitude, strong point source emission and dispersion studies in atmospheric science. The difficulties posed by strong relief, orogenic clouds, and aerosols are minimized by a small field of view, enhanced spectral resolving power, by employing repeat target mode observation strategies, and by comparison to continuous ground based sensor network validation data. GOSAT is a single-instrument Earth observing greenhouse gas mission aboard JAXA's IBUKI satellite in sun-synchronous polar orbit. GOSAT's Fourier-Transform Spectrometer (TANSO-FTS) has been producing total column XCO2 data since January 2009, at a repeat cycle of 3 days, offering great opportunities for temporal monitoring of point sources. GOSAT's 10 km field of view can spatially integrate entire volcanic edifices within one 'shot' in precise target mode. While it doesn't have any spatial scanning or mapping capability, it does have strong spectral resolving power and agile pointing capability to focus on several targets of interest per orbit. Sufficient uncertainty reduction is achieved through comprehensive in-flight vicarious calibration, in close collaboration between NASA and JAXA. Challenges with the on-board pointing mirror system have been compensated for employing custom observation planning strategies, including repeat sacrificial upstream reference points to control pointing mirror motion, empirical individualized target offset compensation, observation pattern simulations to minimize view angle azimuth. Since summer 2010

  12. Interdependencies between temperature and moisture sensitivities of CO2 emissions in European land ecosystems

    NASA Astrophysics Data System (ADS)

    Gritsch, C.; Zimmermann, M.; Zechmeister-Boltenstern, S.

    2015-03-01

    Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO2) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO2. In order to assess CO2 emissions from diverse European soils under different land-use and climate (soil moisture and temperature) we conducted a laboratory incubation experiment. Emission measurements of carbon dioxide under controlled conditions were conducted using soil monoliths of nine sites from the ÉCLAIRE flux network. Sites are located all over Europe; from the UK in the west to the Ukraine in the east; Italy in the south to Finland in the north and can be separated according to four land-uses (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory at the temperatures 5, 10, 15, 20, and 25 °C in a two factorial design of five soil moisture levels (5, 20, 40, 60, 80 (100)% water filled pore space, WFPS), before analysed for CO2 fluxes with an automated laboratory incubation measurement system. Land-use generally had a substantial influence on carbon dioxide fluxes, with the order of CO2 emission rates of the different land-uses being grassland > peatland > forest/arable land (P < 0.001). CO2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO2 emissions between 40-70% WFPS and a positive relationship between CO2 emissions and temperature. The relationship between temperature and CO2 emissions could be well described by a Gaussian model. Q10 values ranged between 0.86-10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q10 was very low. In addition under cold temperatures Q10 varied with moisture contents indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. We found at both coniferous forest sites a strong

  13. Reduction of CO2 using a Rhenium Bipyridine Complex Containing Ancillary BODIPY Moieties

    PubMed Central

    Teesdale, Justin J.; Pistner, Allen J.; Yap, Glenn P.A.; Ma, Ying-Zhong; Lutterman, Daniel A.; Rosenthal, Joel

    2014-01-01

    The reduction of carbon dioxide to chemical fuels such as carbon monoxide is an important challenge in the field of renewable energy conversion. Given the thermodynamic stability of carbon dioxide, it is difficult to efficiently activate this substrate in a selective fashion and the development of new electrocatalysts for CO2 reduction is of prime importance. To this end, we have prepared and studied a new fac-ReI(CO)3 complex supported by a bipyridine ligand containing ancillary BODIPY moieties ([Re(BB2)(CO)3Cl]). Voltammetry experiments revealed that this system displays a rich redox chemistry under N2, as [Re(BB2)(CO)3Cl] can be reduced by up to four electrons at modest potentials. These redox events have been characterized as the ReI/0 couple, and three ligand based reductions – two of which are localized on the BODIPY units. The ability of the BB2 ligand to serve as a non-innocent redox reservoir is manifest in an enhanced electrocatalysis with CO2 as compared to an unsubstituted Re-bipyridine complex lacking BODIPY units ([Re(bpy)(CO)3Cl]). The second order rate constant for reduction of CO2 by [Re(BB2)(CO)3Cl] was measured to be k = 3400 M−1s−1 at an applied potential of −2.0 V versus SCE, which is roughly three times greater than the corresponding unsubstituted Re-bipyridine homologue. Photophysical and photochemical studies were also carried out to determine if [Re(BB2)(CO)3Cl] was a competent platform for CO2 reduction using visible light. These experiments showed that this complex supports unusual excited state dynamics that precludes efficient CO2 reduction and are distinct from those that are typically observed for fac-ReI(CO)3 complexes. PMID:25395735

  14. Reduction of CO2 using a Rhenium Bipyridine Complex Containing Ancillary BODIPY Moieties.

    PubMed

    Teesdale, Justin J; Pistner, Allen J; Yap, Glenn P A; Ma, Ying-Zhong; Lutterman, Daniel A; Rosenthal, Joel

    2014-04-15

    The reduction of carbon dioxide to chemical fuels such as carbon monoxide is an important challenge in the field of renewable energy conversion. Given the thermodynamic stability of carbon dioxide, it is difficult to efficiently activate this substrate in a selective fashion and the development of new electrocatalysts for CO2 reduction is of prime importance. To this end, we have prepared and studied a new fac-Re(I)(CO)3 complex supported by a bipyridine ligand containing ancillary BODIPY moieties ([Re(BB2)(CO)3Cl]). Voltammetry experiments revealed that this system displays a rich redox chemistry under N2, as [Re(BB2)(CO)3Cl] can be reduced by up to four electrons at modest potentials. These redox events have been characterized as the Re(I/0) couple, and three ligand based reductions - two of which are localized on the BODIPY units. The ability of the BB2 ligand to serve as a non-innocent redox reservoir is manifest in an enhanced electrocatalysis with CO2 as compared to an unsubstituted Re-bipyridine complex lacking BODIPY units ([Re(bpy)(CO)3Cl]). The second order rate constant for reduction of CO2 by [Re(BB2)(CO)3Cl] was measured to be k = 3400 M(-1)s(-1) at an applied potential of -2.0 V versus SCE, which is roughly three times greater than the corresponding unsubstituted Re-bipyridine homologue. Photophysical and photochemical studies were also carried out to determine if [Re(BB2)(CO)3Cl] was a competent platform for CO2 reduction using visible light. These experiments showed that this complex supports unusual excited state dynamics that precludes efficient CO2 reduction and are distinct from those that are typically observed for fac-Re(I)(CO)3 complexes. PMID:25395735

  15. Reductive Cleavage of CO2 by Metal-Ligand-Cooperation Mediated by an Iridium Pincer Complex.

    PubMed

    Feller, Moran; Gellrich, Urs; Anaby, Aviel; Diskin-Posner, Yael; Milstein, David

    2016-05-25

    A unique mode of stoichiometric CO2 activation and reductive splitting based on metal-ligand-cooperation is described. The novel Ir hydride complexes [((t)Bu-PNP*)Ir(H)2] (2) ((t)Bu-PNP*, deprotonated (t)Bu-PNP ligand) and [((t)Bu-PNP)Ir(H)] (3) react with CO2 to give the dearomatized complex [((t)Bu-PNP*)Ir(CO)] (4) and water. Mechanistic studies have identified an adduct in which CO2 is bound to the ligand and metal, [((t)Bu-PNP-COO)Ir(H)2] (5), and a di-CO2 iridacycle [((t)Bu-PNP)Ir(H)(C2O4-κC,O)] (6). DFT calculations confirm the formation of 5 and 6 as reversibly formed side products, and suggest an η(1)-CO2 intermediate leading to the thermodynamic product 4. The calculations support a metal-ligand-cooperation pathway in which an internal deprotonation of the benzylic position by the η(1)-CO2 ligand leads to a carboxylate intermediate, which further reacts with the hydride ligand to give complex 4 and water. PMID:27124097

  16. Valuing Non-CO2 GHG Emission Changes in Benefit-Cost Analysis

    EPA Science Inventory

    The climate impacts of greenhouse gas (GHG) emissions impose social costs on society. To date, EPA has not had an approach to estimate the economic benefits of reducing emissions of non-CO2 GHGs (or the costs of increasing them) that is consistent with the methodology underlying...

  17. Negative CO2 emissions via subsurface mineral carbonation in fractured peridotite

    NASA Astrophysics Data System (ADS)

    Kelemen, P. B.; Matter, J.

    2014-12-01

    Uptake of CO2 from surface water via mineral carbonation in peridotite can be engineered to achieve negative CO2 emissions. Reaction with peridotite, e.g., CO2 + olivine (A), serpentine (B) and brucite (C), forms inert, non-toxic, solid carbonates such as magnesite. Experimental studies show that A can be 80% complete in a few hours with 30 micron powders and elevated P(CO2) [1,2,3]. B is slower, but in natural systems the rate of B+C is significant [4]. Methods for capture of dilute CO2 via mineral carbonation [4,5,6,7] are not well known, though CO2 storage via mineral carbonation has been discussed for decades [8,9]. Where crushed peridotite is available, as in mine tailings, increased air or water flow could enhance CO2 uptake at a reasonable cost [4,5]. Here we focus on enhancing subsurface CO2 uptake from surface water flowing in fractured peridotite, in systems driven by thermal convection such as geothermal power plants. Return of depleted water to the surface would draw down CO2 from the air [6,7]. CO2 uptake from water, rate limited by flow in input and output wells, could exceed 1000 tons CO2/yr [7]. If well costs minus power sales were 0.1M to 1M and each system lasts 10 years this costs < 10 to 100 per ton CO2. As for other CCS methods, upscaling requires infrastructure resembling the oil industry. Uptake of 1 Gt CO2/yr at 1000 t/well/yr requires 1M wells, comparable to the number of producing oil and gas wells in the USA. Subsurface CO2 uptake could first be applied in coastal, sub-seafloor peridotite with onshore drilling. Sub-seafloor peridotite is extensive off Oman, New Caledonia and Papua New Guinea, with smaller amounts off Spain, Morocco, USA, etc. This would be a regional contribution, used in parallel with other methods elsewhere. To achieve larger scale is conceivable. There is a giant mass of seafloor peridotite along slow-spreading mid-ocean ridges. Could robotic drills enhance CO2 uptake at a reasonable cost, while fabric chimneys

  18. Optical Emission Spectroscopy for CO2 Dissociation using a Dielectric Barrier Discharge (VADER)

    NASA Astrophysics Data System (ADS)

    Lindon, Michael; Scime, Earl; Gallagher, Michael; Shekhawat, Dushyant; Bergen, Mike; Berry, Dave

    2010-11-01

    VADER (the Versatile Atmospheric Dielectric barrier discharge ExpeRiment) operates at atmospheric pressure and employs high voltage pulses across a quartz dielectric spanning an anode-cathode pair to create a high density, non-thermal, cool plasma in a variety of gasses. In CO2 plasmas, energetic electrons from the tail of the non-thermal electron distribution excite CO2 molecular states and provide a pathway for CO2 dissociation that requires less energy per molecule than conventional thermal dissociation processes. CO2 dissociation by-products can then be used as feedstock gasses for chemical synthesis. Here we have used optical emission spectroscopy in the reaction zone of VADER to monitor the density of reaction products and optimize the dissociation process. The optical emission measurements are correlated with real-time residual gas analyzer (RGA) measurements of the discharge exhaust gas.

  19. Shade trees reduce building energy use and CO2 emissions from power plants.

    PubMed

    Akbari, H

    2002-01-01

    Urban shade trees offer significant benefits in reducing building air-conditioning demand and improving urban air quality by reducing smog. The savings associated with these benefits vary by climate region and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree-planting programs can be designed to have lower costs so that they offer potential savings to communities that plant trees. Our calculations suggest that urban trees play a major role in sequestering CO2 and thereby delay global warming. We estimate that a tree planted in Los Angeles avoids the combustion of 18 kg of carbon annually, even though it sequesters only 4.5-11 kg (as it would if growing in a forest). In this sense, one shade tree in Los Angeles is equivalent to three to five forest trees. In a recent analysis for Baton Rouge, Sacramento, and Salt Lake City, we estimated that planting an average of four shade trees per house (each with a top view cross section of 50 m2) would lead to an annual reduction in carbon emissions from power plants of 16,000, 41,000, and 9000 t, respectively (the per-tree reduction in carbon emissions is about 10-11 kg per year). These reductions only account for the direct reduction in the net cooling- and heating-energy use of buildings. Once the impact of the community cooling is included, these savings are increased by at least 25%. PMID:11833899

  20. Permeability reduction produced by grain reorganization and accumulation of exsolved CO2 during geologic carbon sequestration: a new CO2 trapping mechanism.

    PubMed

    Luhmann, Andrew J; Kong, Xiang-Zhao; Tutolo, Benjamin M; Ding, Kang; Saar, Martin O; Seyfried, William E

    2013-01-01

    Carbon sequestration experiments were conducted on uncemented sediment and lithified rock from the Eau Claire Formation, which consisted primarily of K-feldspar and quartz. Cores were heated to accentuate reactivity between fluid and mineral grains and to force CO(2) exsolution. Measured permeability of one sediment core ultimately reduced by 4 orders of magnitude as it was incrementally heated from 21 to 150 °C. Water-rock interaction produced some alteration, yielding sub-μm clay precipitation on K-feldspar grains in the core's upstream end. Experimental results also revealed abundant newly formed pore space in regions of the core, and in some cases pores that were several times larger than the average grain size of the sediment. These large pores likely formed from elevated localized pressure caused by rapid CO(2) exsolution within the core and/or an accumulating CO(2) phase capable of pushing out surrounding sediment. CO(2) filled the pores and blocked flow pathways. Comparison with a similar experiment using a solid arkose core indicates that CO(2) accumulation and grain reorganization mainly contributed to permeability reduction during the heated sediment core experiment. This suggests that CO(2) injection into sediments may store more CO(2) and cause additional permeability reduction than is possible in lithified rock due to grain reorganization. PMID:23140278

  1. Permeability reduction produced by grain reorganization and accumulation of exsolved CO2 during geologic carbon sequestration: a new CO2 trapping mechanism.

    PubMed

    Luhmann, Andrew J; Kong, Xiang-Zhao; Tutolo, Benjamin M; Ding, Kang; Saar, Martin O; Seyfried, William E

    2013-01-01

    Carbon sequestration experiments were conducted on uncemented sediment and lithified rock from the Eau Claire Formation, which consisted primarily of K-feldspar and quartz. Cores were heated to accentuate reactivity between fluid and mineral grains and to force CO(2) exsolution. Measured permeability of one sediment core ultimately reduced by 4 orders of magnitude as it was incrementally heated from 21 to 150 °C. Water-rock interaction produced some alteration, yielding sub-μm clay precipitation on K-feldspar grains in the core's upstream end. Experimental results also revealed abundant newly formed pore space in regions of the core, and in some cases pores that were several times larger than the average grain size of the sediment. These large pores likely formed from elevated localized pressure caused by rapid CO(2) exsolution within the core and/or an accumulating CO(2) phase capable of pushing out surrounding sediment. CO(2) filled the pores and blocked flow pathways. Comparison with a similar experiment using a solid arkose core indicates that CO(2) accumulation and grain reorganization mainly contributed to permeability reduction during the heated sediment core experiment. This suggests that CO(2) injection into sediments may store more CO(2) and cause additional permeability reduction than is possible in lithified rock due to grain reorganization.

  2. Application of Carbon Isotope Fractionation during the Reduction Process from CO 2 to CH 4

    NASA Astrophysics Data System (ADS)

    Li, Jin; Hu, Guoyi; Zhang, Ying; Yang, Guifang; Cui, Huiying; Cao, Hongming; Hu, Xülong

    The CO 2 reduced to CH 4 pathway is important for the generation of biogas in the geological history. The Quaternary biogenic gas fields in Qaidam Basin of China belong to the CO 2/H 2 reduction biogenic gas. According to the theory of H 2/CO 2 reduction, we have carried out the biosimulation experiments with different occurrences and different initial carbon isotope values of carbon sources. The experimental results indicate that there is a positive correlation between the δ 13C methane values and the δ 13C values of the substrate in products; In response to the existence of excessive substrate, the occurrence of substrate has its effect on the δ 13C methane values. The δ 13C methane values from free CO 2 reduced to CH 4 is relatively lower than those coming from HCO 3- and CO 32- ions. By applying to the Quaternary biogenic gas filed in the east of Qaidam Basin, the source and occurrences of the main substrate CO 2 are discussed, and these have import reference significance for evaluating the biogas resources and searching for favorable exploration areas.

  3. Plant acclimation impacts carbon allocation to isoprene emissions: evidence from past to future CO2 levels

    NASA Astrophysics Data System (ADS)

    de Boer, Hugo J.; van der Laan, Annick; Dekker, Stefan C.; Holzinger, Rupert

    2016-04-01

    Isoprene (C5H8) is produced in plant leaves as a side product of photosynthesis, whereby approximately 0.1-2.0% of the photosynthetic carbon uptake is released back into the atmosphere via isoprene emissions. Isoprene biosynthesis is thought to alleviate oxidative stress, specifically in warm, dry and high-light environments. Moreover, isoprene biosynthesis is influenced by atmospheric CO2 concentrations in the short term (CO2 concentration (Ci), and in the long term (>weeks) via acclimation in photosynthetic biochemistry. In order to understand the effects of CO2-induced climate change on carbon allocation in plants it is therefore important to quantify how isoprene biosynthesis and emissions are effected by both short-term responses and long-term acclimation to rising atmospheric CO2 levels. A promising development for modelling CO2-induced changes in isoprene emissions is the Leaf-Energetic-Status model (referred to as LES-model hereafter, see Harrison et al., 2013 and Morfopoulos et al., 2014). This model simulates isoprene emissions based on the hypothesis that isoprene biosynthesis depends on the imbalance between the photosynthetic electron supply of reducing power and the electron demands of carbon fixation. In addition to environmental conditions, this imbalance is determined by the photosynthetic electron transport capacity (Jmax) and the maximum carboxylation capacity of Rubisco (V cmax). Here we compare predictions of the LES-model with observed isoprene emission responses of Quercus robur (pedunculate oak) specimen that acclimated to CO2 levels representative of the last glacial, the present and the end of this century (200, 400 and 800 ppm, respectively) for two growing seasons. Plants were grown in walk-in growth chambers with tight control of light, temperature, humidity and CO2 concentrations. Photosynthetic biochemical parameters V cmax and Jmax were determined with a Licor LI-6400XT photosynthesis system

  4. Atomic carbon emission from photodissociation of CO2. [planetary atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Wu, C. Y. R.; Phillips, E.; Lee, L. C.; Judge, D. L.

    1978-01-01

    Atomic carbon fluorescence, C I 1561, 1657, and 1931 A, has been observed from photodissociation of CO2, and the production cross sections have been measured. A line emission source provided the primary photons at wavelengths from threshold to 420 A. The present results suggest that the excited carbon atoms are produced by total dissociation of CO2 into three atoms. The cross sections for producing the O I 1304-A fluorescence through photodissociation of CO2 are found to be less than 0.01 Mb in the wavelength region from 420 to 835 A. The present data have implications with respect to photochemical processes in the atmospheres of Mars and Venus.

  5. Dissociative excitation of vacuum ultraviolet emission features by electron impact on molecular gases. 3: CO2

    NASA Technical Reports Server (NTRS)

    Mumma, M. J.; Borst, W. L.; Zipf, E. C.

    1972-01-01

    Vacuum ultraviolet multiplets of C I, C II, and O I were produced by electron impact on CO2. Absolute emission cross sections for these multiplets were measured from threshold to 350 eV. The electrostatically focused electron gun used is described in detail. The atomic multiplets which were produced by dissociative excitation of CO2 and the cross sections at 100 eV are presented. The dependence of the excitation functions on electron energy shows that these multiplets are produced by electric-dipole-allowed transitions in CO2.

  6. China's transportation energy consumption and CO2 emissions from a global perspective

    SciTech Connect

    Yin, Xiang; Chen, Wenying; Eom, Jiyong; Clarke, Leon E.; Kim, Son H.; Patel, Pralit L.; Yu, Sha; Kyle, G. Page

    2015-07-01

    ABSTRACT Rapidly growing energy demand from China's transportation sector in the last two decades have raised concerns over national energy security, local air pollution, and carbon dioxide (CO2) emissions, and there is broad consensus that China's transportation sector will continue to grow in the coming decades. This paper explores the future development of China's transportation sector in terms of service demands, final energy consumption, and CO2 emissions, and their interactions with global climate policy. This study develops a detailed China transportation energy model that is nested in an integrated assessment model—Global Change Assessment Model (GCAM)—to evaluate the long-term energy consumption and CO2 emissions of China's transportation sector from a global perspective. The analysis suggests that, without major policy intervention, future transportation energy consumption and CO2 emissions will continue to rapidly increase and the transportation sector will remain heavily reliant on fossil fuels. Although carbon price policies may significantly reduce the sector's energy consumption and CO2 emissions, the associated changes in service demands and modal split will be modest, particularly in the passenger transport sector. The analysis also suggests that it is more difficult to decarbonize the transportation sector than other sectors of the economy, primarily owing to its heavy reliance on petroleum products.

  7. Variations in mid-ocean ridge CO2 emissions driven by glacial cycles

    NASA Astrophysics Data System (ADS)

    Burley, Jonathan M. A.; Katz, Richard F.

    2015-09-01

    The geological record documents links between glacial cycles and volcanic productivity, both subaerially and, tentatively, at mid-ocean ridges. Sea-level-driven pressure changes could also affect chemical properties of mid-ocean ridge volcanism. We consider how changing sea-level could alter the CO2 emissions rate from mid-ocean ridges on both the segment and global scale. We develop a simplified transport model for a highly incompatible trace element moving through a homogeneous mantle; variations in the concentration and the emission rate of the element are the result of changes in the depth of first silicate melting. The model predicts an average global mid-ocean ridge CO2 emissions rate of 53 Mt/yr or 91 Mt/yr for an average source mantle CO2 concentration of 125 or 215 ppm by weight, in line with other estimates. We show that falling sea level would cause an increase in ridge CO2 emissions about 100 kyrs after the causative sea level change. The lag and amplitude of the response are sensitive to mantle permeability and plate spreading rate. For a reconstructed sea-level time series of the past million years, we predict variations of up to 12% in global mid-ocean ridge CO2 emissions.

  8. CO2 hydrogenation to formate and methanol as an alternative to photo- and electrochemical CO2 reduction

    DOE PAGES

    Wang, Wan -Hui; Himeda, Yuichiro; Muckerman, James T.; Manbeck, Gerald F.; Fujita, Etsuko

    2015-09-03

    In this study, carbon dioxide is one of the end products of combustion, and is not a benign component of the atmosphere. The concentration of CO2 in the atmosphere has reached unprecedented levels and continues to increase owing to an escalating rate of fossil fuel combustion, causing concern about climate change and rising sea levels. In view of the inevitable depletion of fossil fuels, a possible solution to this problem is the recycling of carbon dioxide, possibly captured at its point of generation, to fuels. Researchers in this field are using solar energy for CO2 activation and utilization in severalmore » ways: (i) so-called artificial photosynthesis using photo-induced electrons; (ii) bulk electrolysis of a CO2 saturated solution using electricity produced by photovoltaics; (iii) CO2 hydrogenation using solar-produced H2; and (iv) the thermochemical reaction of metal oxides at extremely high temperature reached by solar collectors. Since the thermodynamics of CO2 at high temperature (> 1000 ºC) are quite different from those near room temperature, only chemistry below 200 ºC is discussed in this review.« less

  9. 40 CFR 600.210-12 - Calculation of fuel economy and CO2 emission values for labeling.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Calculation of fuel economy and CO2... Calculation of fuel economy and CO2 emission values for labeling. (a) General labels. Except as specified in paragraphs (d) and (e) of this section, fuel economy and CO2 emissions for general labels may be...

  10. 40 CFR 600.210-12 - Calculation of fuel economy and CO2 emission values for labeling.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Calculation of fuel economy and CO2... Calculation of fuel economy and CO2 emission values for labeling. (a) General labels. Except as specified in paragraphs (d) and (e) of this section, fuel economy and CO2 emissions for general labels may be...

  11. Indirect CO2 Emission Implications of Energy System Pathways: Linking IO and TIMES Models for the UK.

    PubMed

    Daly, Hannah E; Scott, Kate; Strachan, Neil; Barrett, John

    2015-09-01

    Radical changes to current national energy systems-including energy efficiency and the decarbonization of electricity-will be required in order to meet challenging carbon emission reduction commitments. Technology explicit energy system optimization models (ESOMs) are widely used to define and assess such low-carbon pathways, but these models only account for the emissions associated with energy combustion and either do not account for or do not correctly allocate emissions arising from infrastructure, manufacturing, construction and transport associated with energy technologies and fuels. This paper addresses this shortcoming, through a hybrid approach that estimates the upstream CO2 emissions across current and future energy technologies for the UK using a multiregional environmentally extended input-output model, and explicitly models the direct and indirect CO2 emissions of energy supply and infrastructure technologies within a national ESOM (the UK TIMES model). Results indicate the large significance of nondomestic indirect emissions, particularly coming from fossil fuel imports, and finds that the marginal abatement cost of mitigating all emissions associated with UK energy supply is roughly double that of mitigating only direct emissions in 2050. PMID:26053304

  12. Indirect CO2 Emission Implications of Energy System Pathways: Linking IO and TIMES Models for the UK.

    PubMed

    Daly, Hannah E; Scott, Kate; Strachan, Neil; Barrett, John

    2015-09-01

    Radical changes to current national energy systems-including energy efficiency and the decarbonization of electricity-will be required in order to meet challenging carbon emission reduction commitments. Technology explicit energy system optimization models (ESOMs) are widely used to define and assess such low-carbon pathways, but these models only account for the emissions associated with energy combustion and either do not account for or do not correctly allocate emissions arising from infrastructure, manufacturing, construction and transport associated with energy technologies and fuels. This paper addresses this shortcoming, through a hybrid approach that estimates the upstream CO2 emissions across current and future energy technologies for the UK using a multiregional environmentally extended input-output model, and explicitly models the direct and indirect CO2 emissions of energy supply and infrastructure technologies within a national ESOM (the UK TIMES model). Results indicate the large significance of nondomestic indirect emissions, particularly coming from fossil fuel imports, and finds that the marginal abatement cost of mitigating all emissions associated with UK energy supply is roughly double that of mitigating only direct emissions in 2050.

  13. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO 2 concentration data

    DOE PAGES

    Ogle, Stephen; Davis, Kenneth J.; Lauvaux, Thomas; Schuh, Andrew E.; Cooley, Dan; West, Tristram O.; Heath, L.; Miles, Natasha; Richardson, S. J.; Breidt, F. Jay; et al

    2015-03-10

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country’s contribution to GHG concentrations in the atmosphere. Verification could include a variety of evidence, but arguably the most convincing verification would be confirmation of a change in GHG concentrations in the atmosphere that is consistent with reported emissions to the UNFCCC. We report here on a case study evaluating this option based on a prototype atmospheric CO2 measurement network deployed in the Mid-Continent Region of themore » conterminous United States. We found that the atmospheric CO2 measurement data did verify the accuracy of the emissions inventory within the confidence limits of the emissions estimates, suggesting that this technology could be further developed and deployed more widely in the future for verifying reported emissions.« less

  14. Future CO2 emissions and climate change from existing energy infrastructure.

    PubMed

    Davis, Steven J; Caldeira, Ken; Matthews, H Damon

    2010-09-10

    Slowing climate change requires overcoming inertia in political, technological, and geophysical systems. Of these, only geophysical warming commitment has been quantified. We estimated the commitment to future emissions and warming represented by existing carbon dioxide-emitting devices. We calculated cumulative future emissions of 496 (282 to 701 in lower- and upper-bounding scenarios) gigatonnes of CO2 from combustion of fossil fuels by existing infrastructure between 2010 and 2060, forcing mean warming of 1.3 degrees C (1.1 degrees to 1.4 degrees C) above the pre-industrial era and atmospheric concentrations of CO2 less than 430 parts per million. Because these conditions would likely avoid many key impacts of climate change, we conclude that sources of the most threatening emissions have yet to be built. However, CO2-emitting infrastructure will expand unless extraordinary efforts are undertaken to develop alternatives.

  15. GOSAT/TANSO-FTS Measurement of Volcanic and Geothermal CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Carn, Simon A.; Newhall, Christopher G.

    2010-05-01

    Approximately one tenth of the Earth's human population lives in direct reach of volcanic hazards. Being able to provide sufficiently early and scientifically sound warning is a key to volcanic hazard mitigation. Quantitative time-series monitoring of volcanic CO2 emissions will likely play a key role in such early warning activities in the future. Impending volcanic eruptions or any potentially disastrous activity that involves movement of magma in the subsurface, is often preceded by an early increase of CO2 emissions. Conventionally, volcanic CO2 monitoring is done either in campaigns of soil emission measurements (grid of one-time measuring points) that are labor intensive and slow, or by ground-based remote FTIR measurements in emission plumes. These methods are not easily available at all sites of potential activity and prohibitively costly to employ on a large number of volcanoes. In addition, both of these ground-based approaches pose a significant risk to the workers conducting these measurements. Some aircraft-based measurements have been conducted as well in the past, however these are limited by the usually meager funding situation of individual observatories, the hazard such flights pose to equipment and crew, and by the inaccessibility of parts of the plume due to ash hazards. The core motivation for this study is therefore to develop a method for volcanic CO2 monitoring from space that will provide sufficient coverage, resolution, and data quality for an application to quantitative time series monitoring and correlation with other available datasets, from a safe distance and with potentially global reach. In summary, the purpose of the proposed research is to quantify volcanic CO2 emissions using satellite-borne observations. Quantitative estimates will be useful for warning of impending volcanic eruptions, and assessing the contribution of volcanic CO2 to global GHG. Our approach encompasses method development and testing for the detection of

  16. Hybrid life-cycle assessment (LCA) of CO2 emission with management alternatives for household food wastes in Japan.

    PubMed

    Inaba, Rokuta; Nansai, Keisuke; Fujii, Minoru; Hashimoto, Seiji

    2010-06-01

    In this study, we conducted a hybrid life-cycle assessment (LCA) to evaluate reductions in CO(2) emissions by food waste biogasification of household food wastes in Japan. Two alternative scenarios were examined. In one alternative (Ref), all combustible municipal solid wastes (MSWs), including food waste, are incinerated. In the other (Bio), food waste is biogasified, while the other combustible wastes are incinerated. An inventory analysis of energy and material flow in the MSW management system was conducted. Subsequently, the inventory data were summarized into an input-output format, and a make-use input-output framework was applied. Furthermore, a production equilibrium model was established using a matrix representing the input- output relationship of energy and materials among the processes and sectors. Several levels of power generation efficiency from incineration were applied as a sensitivity analysis. The hybrid LCA indicated that the difference between the Bio and Ref scenarios, from the perspective of CO( 2) emissions, is relatively small. However, a 13-14% reduction of CO(2) emissions of the total waste management sector in Japan may be achieved by improving the efficiency of power generation from incineration from 10% to 25%.

  17. Hybrid life-cycle assessment (LCA) of CO2 emission with management alternatives for household food wastes in Japan.

    PubMed

    Inaba, Rokuta; Nansai, Keisuke; Fujii, Minoru; Hashimoto, Seiji

    2010-06-01

    In this study, we conducted a hybrid life-cycle assessment (LCA) to evaluate reductions in CO(2) emissions by food waste biogasification of household food wastes in Japan. Two alternative scenarios were examined. In one alternative (Ref), all combustible municipal solid wastes (MSWs), including food waste, are incinerated. In the other (Bio), food waste is biogasified, while the other combustible wastes are incinerated. An inventory analysis of energy and material flow in the MSW management system was conducted. Subsequently, the inventory data were summarized into an input-output format, and a make-use input-output framework was applied. Furthermore, a production equilibrium model was established using a matrix representing the input- output relationship of energy and materials among the processes and sectors. Several levels of power generation efficiency from incineration were applied as a sensitivity analysis. The hybrid LCA indicated that the difference between the Bio and Ref scenarios, from the perspective of CO( 2) emissions, is relatively small. However, a 13-14% reduction of CO(2) emissions of the total waste management sector in Japan may be achieved by improving the efficiency of power generation from incineration from 10% to 25%. PMID:19942648

  18. Nanoporous copper incorporated platinum composites for electrocatalytic reduction of CO2 in ionic liquid BMIMBF4

    NASA Astrophysics Data System (ADS)

    Feng, Qiuju; Liu, Suqin; Wang, Xuanyun; Jin, Ganhua

    2012-04-01

    A three-dimensional porous nanostructure electrode composed of copper skeletons and platinum shells (NPC-Pt) was prepared by electroless plating for the first time. The electrochemical behavior of this electrode for electrocatalytic reduction CO2 in ionic liquid, 1-butyl-3-methylimidazoliumtetrafluoborate (BMIMBF4), had been studied by cyclic voltammogram and electrochemical impedance spectroscopy with a reduction peak at -2.24 V (vs. Ag) which was more positive 180 mV than that obtained on a pure platinum electrode. The electrolyses experiments were carried out in an undivided cell under mild conditions without any toxic solvents, catalysts and supporting electrolytes, affording the dimethyl carbonate in a good yield (81%). In addition, the current for the CO2 reduction at NPC-Pt electrode was stable, with a higher current density and current efficiency (83%). Moreover, current efficiency remained after reusing it for five times.

  19. Exploring the intermediates of photochemical CO2 reduction: reaction of Re(dmb)(CO)3 COOH with CO2.

    PubMed

    Agarwal, Jay; Sanders, Brian C; Fujita, Etsuko; Schaefer, Henry F; Harrop, Todd C; Muckerman, James T

    2012-07-11

    We have investigated the reaction of Re(dmb)(CO)(3)COOH with CO(2) using density functional theory, and propose a mechanism for the production of CO. This mechanism supports the role of Re(dmb)(CO)(3)COOH as a key intermediate in the formation of CO. Our new experimental work supports the proposed scheme.

  20. 40 CFR 1037.106 - Exhaust emission standards for CO2 for tractors above 26,000 pounds GVWR.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.106 Exhaust emission standards for CO2 for tractors... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Exhaust emission standards for CO2...

  1. 40 CFR 1037.106 - Exhaust emission standards for CO2 for tractors above 26,000 pounds GVWR.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.106 Exhaust emission standards for CO2 for tractors... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Exhaust emission standards for CO2...

  2. 40 CFR 1037.106 - Exhaust emission standards for CO2 for tractors above 26,000 pounds GVWR.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.106 Exhaust emission standards for CO2 for tractors... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Exhaust emission standards for CO2...

  3. High-resolution mapping of combustion processes and implications for CO2 emissions

    NASA Astrophysics Data System (ADS)

    Wang, R.; Tao, S.; Ciais, P.; Shen, H. Z.; Huang, Y.; Chen, H.; Shen, G. F.; Wang, B.; Li, W.; Zhang, Y. Y.; Lu, Y.; Zhu, D.; Chen, Y. C.; Liu, X. P.; Wang, W. T.; Wang, X. L.; Liu, W. X.; Li, B. G.; Piao, S. L.

    2013-05-01

    High-resolution mapping of fuel combustion and CO2 emission provides valuable information for modeling pollutant transport, developing mitigation policy, and for inverse modeling of CO2 fluxes. Previous global emission maps included only few fuel types, and emissions were estimated on a grid by distributing national fuel data on an equal per capita basis, using population density maps. This process distorts the geographical distribution of emissions within countries. In this study, a sub-national disaggregation method (SDM) of fuel data is applied to establish a global 0.1° × 0.1° geo-referenced inventory of fuel combustion (PKU-FUEL) and corresponding CO2 emissions (PKU-CO2) based upon 64 fuel sub-types for the year 2007. Uncertainties of the emission maps are evaluated using a Monte Carlo method. It is estimated that CO2 emission from combustion sources including fossil fuel, biomass, and solid wastes in 2007 was 11.2 Pg C yr-1 (9.1 Pg C yr-1 and 13.3 Pg C yr-1 as 5th and 95th percentiles). Of this, emission from fossil fuel combustion is 7.83 Pg C yr-1, which is very close to the estimate of the International Energy Agency (7.87 Pg C yr-1). By replacing national data disaggregation with sub-national data in this study, the average 95th minus 5th percentile ranges of CO2 emission for all grid points can be reduced from 417 to 68.2 Mg km-2 yr-1. The spread is reduced because the uneven distribution of per capita fuel consumptions within countries is better taken into account by using sub-national fuel consumption data directly. Significant difference in per capita CO2 emissions between urban and rural areas was found in developing countries (2.08 vs. 0.598 Mg C/(cap. × yr)), but not in developed countries (3.55 vs. 3.41 Mg C/(cap. × yr)). This implies that rapid urbanization of developing countries is very likely to drive up their emissions in the future.

  4. Improved Fossil/Industrial CO2 Emissions Modeling for the North American Carbon Program

    NASA Astrophysics Data System (ADS)

    Gurney, K. R.; Seib, B.; Mendoza, D.; Knox, S.; Fischer, M.; Murtishaw, S.

    2006-12-01

    The quantification of fossil fuel CO2 emissions has implications for a wide variety of scientific and policy- related questions. Improvement in inverse-estimated carbon fluxes, country-level carbon budgeting, analysis of regional emissions trading systems, and targeting of observational systems are all important applications better served by improvements in understanding where and when fossil fuel/industrial CO2 is emitted. Traditional approaches to quantifying fossil/industrial CO2 emissions have relied on national sales/consumption of fossil fuels with secondary spatial footprints performed via proxies such as population. This approach has provided global spatiotemporal resolution of one degree/monthly. In recent years the need has arisen for emission estimates that not only achieve higher spatiotemporal scales but include a process- level component. This latter attribute provides dynamic linkages between energy policy/decisionmaking and emissions for use in projecting changes to energy systems and the implications these changes may have on climate change. We have embarked on a NASA-funded research strategy to construct a process-level fossil/industrial CO2 emissions model/database for North America that will resolve fossil/industrial CO2 emissions hourly and at 36 km. This project is a critical component of the North American Carbon Program. Our approach builds off of many decades of air quality monitoring for regulated pollutants such as NOx, VOCs and CO that has been performed by regional air quality managers, states, and the Environmental Protection Agency in the United States. By using the highly resolved monitoring data supplied to the EPA, we have computed CO2 emissions for residential, commercial/industrial, transportation, and biogenic sources. This effort employs a new emissions modeling system (CONCEPT) that spatially and temporally distributes the monitored emissions across the US. We will provide a description of the methodology we have employed, the

  5. Improved Fossil/Industrial CO2 Emissions Modeling for the North American Carbon Program

    NASA Astrophysics Data System (ADS)

    Gurney, K. R.; Seib, B.; Mendoza, D.; Knox, S.; Fischer, M.; Murtishaw, S.

    2005-05-01

    The quantification of fossil fuel CO2 emissions has implications for a wide variety of scientific and policy- related questions. Improvement in inverse-estimated carbon fluxes, country-level carbon budgeting, analysis of regional emissions trading systems, and targeting of observational systems are all important applications better served by improvements in understanding where and when fossil fuel/industrial CO2 is emitted. Traditional approaches to quantifying fossil/industrial CO2 emissions have relied on national sales/consumption of fossil fuels with secondary spatial footprints performed via proxies such as population. This approach has provided global spatiotemporal resolution of one degree/monthly. In recent years the need has arisen for emission estimates that not only achieve higher spatiotemporal scales but include a process- level component. This latter attribute provides dynamic linkages between energy policy/decisionmaking and emissions for use in projecting changes to energy systems and the implications these changes may have on climate change. We have embarked on a NASA-funded research strategy to construct a process-level fossil/industrial CO2 emissions model/database for North America that will resolve fossil/industrial CO2 emissions hourly and at 36 km. This project is a critical component of the North American Carbon Program. Our approach builds off of many decades of air quality monitoring for regulated pollutants such as NOx, VOCs and CO that has been performed by regional air quality managers, states, and the Environmental Protection Agency in the United States. By using the highly resolved monitoring data supplied to the EPA, we have computed CO2 emissions for residential, commercial/industrial, transportation, and biogenic sources. This effort employs a new emissions modeling system (CONCEPT) that spatially and temporally distributes the monitored emissions across the US. We will provide a description of the methodology we have employed, the

  6. Spectral albedo and emissivity of CO2 in Martian polar caps - Model results

    NASA Technical Reports Server (NTRS)

    Warren, Stephen G.; Wiscombe, Warren J.; Firestone, John F.

    1990-01-01

    In this paper, a snow albedo model previously developed for terrestrial snow is extended to the case of CO2 snow on Mars. Pure CO2 snow is calculated to have high albedo at visible wavelengths but not as high as that of water snow. At any given wavelength, the primary variable controlling albedo and emissivity is the snow grain size, with albedo decreasing and emissivity increasing as grain size increases. Observations that red albedo is much higher than blue albedo in the Martian south polar cap indicates that the snow or the atmosphere is contaminated with red dust. The absorption coefficient of CO2 ice in the thermal infrared is two to three orders of magnitude smaller than that measured for H2O ice. CO2 snow emissivity is therefore much lower than H2O snow, varying substantially with wavelength and quite sensitive to grain size and emission angle. Factors tending to increase emissivity are large grain size, small emission angle, and large concentrations of dust or water.

  7. China's growing CO2 emissions--a race between increasing consumption and efficiency gains.

    PubMed

    Peters, Glen P; Weber, Christopher L; Guan, Dabo; Hubacek, Klaus

    2007-09-01

    China's rapidly growing economy and energy consumption are creating serious environmental problems on both local and global scales. Understanding the key drivers behind China's growing energy consumption and the associated CO2 emissions is critical for the development of global climate policies and provides insight into how other emerging economies may develop a low emissions future. Using recently released Chinese economic input-output data and structural decomposition analysis we analyze how changes in China's technology, economic structure, urbanization, and lifestyles affect CO2 emissions. We find that infrastructure construction and urban household consumption, both in turn driven by urbanization and lifestyle changes, have outpaced efficiency improvements in the growth of CO2 emissions. Net trade had a small effect on total emissions due to equal, but significant, growth in emissions from the production of exports and emissions avoided by imports. Technology and efficiency improvements have only partially offset consumption growth, but there remains considerable untapped potential to reduce emissions by improving both production and consumption systems. As China continues to rapidly develop there is an opportunity to further implement and extend policies, such as the Circular Economy, that will help China avoid the high emissions path taken by today's developed countries. PMID:17937264

  8. China's growing CO2 emissions--a race between increasing consumption and efficiency gains.

    PubMed

    Peters, Glen P; Weber, Christopher L; Guan, Dabo; Hubacek, Klaus

    2007-09-01

    China's rapidly growing economy and energy consumption are creating serious environmental problems on both local and global scales. Understanding the key drivers behind China's growing energy consumption and the associated CO2 emissions is critical for the development of global climate policies and provides insight into how other emerging economies may develop a low emissions future. Using recently released Chinese economic input-output data and structural decomposition analysis we analyze how changes in China's technology, economic structure, urbanization, and lifestyles affect CO2 emissions. We find that infrastructure construction and urban household consumption, both in turn driven by urbanization and lifestyle changes, have outpaced efficiency improvements in the growth of CO2 emissions. Net trade had a small effect on total emissions due to equal, but significant, growth in emissions from the production of exports and emissions avoided by imports. Technology and efficiency improvements have only partially offset consumption growth, but there remains considerable untapped potential to reduce emissions by improving both production and consumption systems. As China continues to rapidly develop there is an opportunity to further implement and extend policies, such as the Circular Economy, that will help China avoid the high emissions path taken by today's developed countries.

  9. Future land-use change emissions: CO2, BVOC and wildfire

    NASA Astrophysics Data System (ADS)

    Arneth, A.; Knorr, W.; Hantson, S.; Anthoni, P.; Szogs, S.

    2015-12-01

    Historical land-use (LUC) change is known to have been a large source of CO2 emissions, mostly from deforestation: the equivalent of around 1/3 of today's CO2 in the atmosphere arises from LUC. And LUC will continue into the future, although the expected area change, the type of LUC (deforestation vs. afforestation/reforestation) and regions where the LUC will take place will differ greatly, depending on the future scenario. But LUC is not only of importance for projecting emissions of CO2. It also affects greatly emissions of biogenic volatile organic carbon, and from wildfires - all of which are important for the quantification of precursor substances relevant to air quality, and interactions with climate change. We show here that accounting for future socio-economic developments and LUC scenarios has the potential to override climate change and effects of CO2 fertilisation on fire and BVOC emission, regionally and in some cases also globally. Simulation experiments with the dynamic global vegetation model LPJ-GUESS will be performed, covering the 20th and 21st century, and assessing a rage of future population growth, LUC and climate change scenarios. For wildfire emissions, we find that burned area and emissions depend greatly on the type of population growth scenario, and on the distribution of urban vs rural population. BVOC emissions depend greatly on the amount and location of deforestation vs the region and magnitude of forest expansion in response to warming, such as through expansion of vegetation in the northern hemisphere, and via reforestation/afforestation. LUC so far has not been given sufficient attention for simulations of future air quality-climate interactions. In terms of terrestrial precursor emissions of atmospherically reactive substances our simulations clearly demonstrate the importance of including LUC in combination with vegetation that responds dynamically to changes in climate and atmospheric CO2 levels.

  10. Driving forces in energy-related CO2 emissions in south and east coastal China: commonality and variations

    NASA Astrophysics Data System (ADS)

    Gao, C.; Liu, Y.; Jin, J.; Wei, T.

    2015-12-01

    East and south coastal China contributes to respectively about 30% and 8% of CO2 emissions in China and the world, and therefore play a critical role in achieving the national goal of emission reduction to mitigate the global warming. It also serves as a benchmark for the less developed regions of China, in terms of achieving the developed world's human development standard under lower per capita emissions. We analyze the driving forces of emissions in this region and their provincial characteristics by applying the Logarithmic Mean Divisia Index method. Our findings show that emissions have been doubled during the period from 2000 to 2012, along with three and two folds increase in economy and energy consumption, respectively. This suggests a persistent lock between economic growth and emissions, even in this socioeconomically advanced region in China. Provincial difference in annual emission growth reveals three distinguished low-carbon developmental stages, owning mainly to the effectiveness of energy efficiency in reducing emission growth. This may explain why previous climate policies have aimed to reduce carbon intensity. These results indicate that targeted measures on enhancing energy efficiency in the short term and de-carbonization of both the economic and energy structure in the long term can lower the emission growth more effectively and efficiently. They also suggest that factor-driven emission reduction strategies and policies are needed in the geographically and socioeconomically similar regions.

  11. Dynamics of diffuse CO2 emission and eruptive cycle at Cerro Negro volcano, Nicaragua

    NASA Astrophysics Data System (ADS)

    Rodriguez, F.; Melian, G.; Barrancos, J.; Padilla, G.; Diaz, M.; Calvo, D.; Nolasco, D.; Perez, N.; Hernandez Perez, P. A.; Ibarra, M.; Strauch, W.; Muñoz, A.

    2009-12-01

    Cerro Negro volcano is the youngest of a group of cinder cones NW of Las Pilas at 25 km from León (Nicaragua) with 685 meters above sea level and one of the most active volcanoes of Nicaragua. It has erupted 21 times since its birth in 1850, with an eruptive cycle about 7-8 years. Since the last eruption, occurred on 5 August 1999, with erupted lava flows and ash clouds together with gas emissions, a research collaboration program between INETER and ITER was established for monitoring diffuse CO2 emissions from Cerro Negro. Since then, ten CO2 surface efflux surveys have been undertaken covering an area of 0,6 km2, in order to evaluate the spatial and temporal variations of CO2 degassing rate in relation with the eruptive cycle of Cerro Negro. Soil CO2 efflux measurements were performed always by means of a portable NDIR sensor according to the accumulation chamber method. A total diffuse CO2 emission output of 1869 t d-1 was estimated for the 1999 survey; just 3 months after the 1999 eruption which can be considered within the post-eruptive phase. For the 2002 and 2003 surveys, considered within the inter-eruptive phase, a clear decreasing tendency on the total diffuse CO2 output was observed, with estimates of 431 and 84 t d-1, respectively. However, during the 2004 a slightly increase on the total diffuse CO2 emission was observed, reaching up to 256 t d-1. The observed relatively increase was addressed to the occurrence of a seismic swarm at Cerro Negro during the survey. The yearly surveys performed at Cerro Negro from 2005 until present, have always shown background levels of CO2 emission, with 68, 38, 45, 10 and 12 t d-1, respectively. The temporal evolution of the diffuse CO2 emissions from Cerro Negro will allow us to determine the typical range of seasonal or other transient departures from its normal or “baseline” behaviour and its relation with the eruptive cycle.

  12. Diurnal tracking of anthropogenic CO2 emissions in the Los Angeles basin megacity during spring 2010

    NASA Astrophysics Data System (ADS)

    Newman, S.; Jeong, S.; Fischer, M. L.; Xu, X.; Haman, C. L.; Lefer, B.; Alvarez, S.; Rappenglueck, B.; Kort, E. A.; Andrews, A. E.; Peischl, J.; Gurney, K. R.; Miller, C. E.; Yung, Y. L.

    2013-04-01

    Attributing observed CO2 variations to human or natural cause is critical to deducing and tracking emissions from observations. We have used in situ CO2, CO, and planetary boundary layer height (PBLH) measurements recorded during the CalNex-LA (CARB et al., 2008) ground campaign of 15 May-15 June 2010, in Pasadena, CA, to deduce the diurnally varying anthropogenic component of observed CO2 in the megacity of Los Angeles (LA). This affordable and simple technique, validated by carbon isotope observations and WRF-STILT (Weather Research and Forecasting model - Stochastic Time-Inverted Lagrangian Transport model) predictions, is shown to robustly attribute observed CO2 variation to anthropogenic or biogenic origin over the entire diurnal cycle. During CalNex-LA, local fossil fuel combustion contributed up to ~50% of the observed CO2 enhancement overnight, and ~100% of the enhancement near midday. This suggests that sufficiently accurate total column CO2 observations recorded near midday, such as those from the GOSAT or OCO-2 satellites, can potentially be used to track anthropogenic emissions from the LA megacity.

  13. Mapping man-made CO2 emissions using satellite-observed nighttime lights

    NASA Astrophysics Data System (ADS)

    Oda, T.; Maksyutov, S. S.; Andres, R. J.; Elvidge, C.; Baugh, K.; Hsu, F. C.; Roman, M. O.

    2015-12-01

    The Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC) is a global high spatial resolution (1x1km) emission dataset for CO2 emissions from fossil fuel combustion. The original version of ODIAC was developed at the Japanese Greenhouse Gas Observing Satellite (GOSAT) project to prescribe their inverse model. ODIAC first introduced the combined use of satellite-observed nighttime light data and individual power plant emission/geolocation information to estimate the spatial extent of fossil fuel CO2. The ODIAC emission data has been widely used by the international carbon cycle research community and appeared in a number of publications in the literature. Since its original publication in 2011, we have made numerous modifications to the ODIAC emission model and the emission data have been updated on annual basis. We are switching from BP statistical data based emission estimates to estimates made by Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory. In recent versions of ODIAC data, the emission seasonality has been adopted from the CDIAC monthly emission dataset. The emissions from international bunkers, which are not included in the CDIAC gridded emission data, are estimated using the UN Energy Database and included with the spatial distributions. In the next version of ODIAC emission model, we will explore the use of satellite data collected by the NASA's Suomi National Polar-orbiting Partnership (NPP) satellite. We will estimate emission spatial distributions using global 500x500m nighttime lights data created from VIIRS data. We will also utilize a combustion detection algorithm Nightfire developed at NOAA National Geophysical Data Center to map gas flaring emissions. We also plan to expand our two emission sector emission distributing approach (power plant emission and non-point source emissions) by introducing a transportation emission sector which should improve emission distributions in urban and rural areas.

  14. Effects of simulated spring thaw of permafrost from mineral cryosol on CO2 emissions and atmospheric CH4 uptake

    NASA Astrophysics Data System (ADS)

    Stackhouse, Brandon T.; Vishnivetskaya, Tatiana A.; Layton, Alice; Chauhan, Archana; Pfiffner, Susan; Mykytczuk, Nadia C.; Sanders, Rebecca; Whyte, Lyle G.; Hedin, Lars; Saad, Nabil; Myneni, Satish; Onstott, Tullis C.

    2015-09-01

    Previous studies investigating organic-rich tundra have reported that increasing biodegradation of Arctic tundra soil organic carbon (SOC) under warming climate regimes will cause increasing CO2 and CH4 emissions. Organic-poor, mineral cryosols, which comprise 87% of Arctic tundra, are not as well characterized. This study examined biogeochemical processes of 1 m long intact mineral cryosol cores (1-6% SOC) collected in the Canadian high Arctic. Vertical profiles of gaseous and aqueous chemistry and microbial composition were related to surface CO2 and CH4 fluxes during a simulated spring/summer thaw under light versus dark and in situ versus water saturated treatments. CO2 fluxes attained 0.8 ± 0.4 mmol CO2 m-2 h-1 for in situ treatments, of which 85 ± 11% was produced by aerobic SOC oxidation, consistent with field observations and metagenomic analyses indicating aerobic heterotrophs were the dominant phylotypes. The Q10 values of CO2 emissions ranged from 2 to 4 over the course of thawing. CH4 degassing occurred during initial thaw; however, all cores were CH4 sinks at atmospheric concentration CH4. Atmospheric CH4 uptake rates ranged from -126 ± 77 to -207 ± 7 nmol CH4 m-2 h-1 with CH4 consumed between 0 and 35 cm depth. Metagenomic and gas chemistry analyses revealed that high-affinity Type II methanotrophic sequence abundance and activity were highest between 0 and 35 cm depth. Microbial sulfate reduction dominated the anaerobic processes, outcompeting methanogenesis for H2 and acetate. Fluxes, microbial community composition, and biogeochemical rates indicate that mineral cryosols of Axel Heiberg Island act as net CO2 sources and atmospheric CH4 sinks during summertime thaw under both in situ and water saturated states.

  15. A multiyear, global gridded fossil fuel CO2 emission data product: Evaluation and analysis of results

    NASA Astrophysics Data System (ADS)

    Asefi-Najafabady, S.; Rayner, P. J.; Gurney, K. R.; McRobert, A.; Song, Y.; Coltin, K.; Huang, J.; Elvidge, C.; Baugh, K.

    2014-09-01

    High-resolution, global quantification of fossil fuel CO2 emissions is emerging as a critical need in carbon cycle science and climate policy. We build upon a previously developed fossil fuel data assimilation system (FFDAS) for estimating global high-resolution fossil fuel CO2 emissions. We have improved the underlying observationally based data sources, expanded the approach through treatment of separate emitting sectors including a new pointwise database of global power plants, and extended the results to cover a 1997 to 2010 time series at a spatial resolution of 0.1°. Long-term trend analysis of the resulting global emissions shows subnational spatial structure in large active economies such as the United States, China, and India. These three countries, in particular, show different long-term trends and exploration of the trends in nighttime lights, and population reveal a decoupling of population and emissions at the subnational level. Analysis of shorter-term variations reveals the impact of the 2008-2009 global financial crisis with widespread negative emission anomalies across the U.S. and Europe. We have used a center of mass (CM) calculation as a compact metric to express the time evolution of spatial patterns in fossil fuel CO2 emissions. The global emission CM has moved toward the east and somewhat south between 1997 and 2010, driven by the increase in emissions in China and South Asia over this time period. Analysis at the level of individual countries reveals per capita CO2 emission migration in both Russia and India. The per capita emission CM holds potential as a way to succinctly analyze subnational shifts in carbon intensity over time. Uncertainties are generally lower than the previous version of FFDAS due mainly to an improved nightlight data set.

  16. Reduction of CO2 using a Rhenium Bipyridine Complex Containing Ancillary BODIPY Redox Reservoirs

    SciTech Connect

    Teesdale, Justin; Pistner, Allen; Yapp, Glenn P. A.; Ma, Yingzhong; Lutterman, Daniel A; Rosenthal, Joel

    2014-01-01

    The reduction of carbon dioxide to chemical fuels such as carbon monoxide is an important challenge in the field of renewable energy conversion. Given the thermodynamic stability of carbon dioxide, it is difficult to efficiently activate this substrate in a selective fashion and the development of new electrocatalysts for CO2 reduction is of prime importance. To this end, we have prepared and studied a new fac-ReI(CO)3 complex supported by a bipyridine ligand containing ancillary BODIPY moieties ([Re(BB2)(CO)3Cl]). Voltammetry experiments revealed that this system displays a rich redox chemistry under N2, as [Re(BB2)(CO)3Cl] can be reduced by up to four electrons at modest potentials. These redox events have been characterized as the ReI/0 couple, and three ligand based reductions two of which are localized on the BODIPY units. The ability of the BB2 ligand to serve as a noninnocent redox reservoir is manifest in an enhanced electrocatalysis with CO2 as compared to an unsubstituted Re-bipyridine complex lacking BODIPY units ([Re(bpy)(CO)3Cl]). The second order rate constant for reduction of CO2 by [Re(BB2)(CO)3Cl] was measured to be k = 3400 M 1s 1 at an applied potential of 2.0 V versus SCE, which is roughly three times greater than the corresponding unsubstituted Re-bipyridine homologue. Photophysical and photochemical studies were also carried out to determine if [Re(BB2)(CO)3Cl] was a competent platform for CO2 reduction using visible light. These experiments showed that this complex supports unusual excited state dynamics that are not typically observed for fac- ReI(CO)3 complexes.

  17. Regional Heterogeneity in the Rates of Warming from CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Ricke, K.; Caldeira, K.

    2015-12-01

    While it is commonly understood that the magnitudes of global warming from anthropogenic emissions are and will be spatially heterogeneous, little work has been done exploring heterogeneity in the timing of effects from an emission of carbon dioxide (CO2). Using the results from the Coupled Model Intercomparison Project v5 (CMIP5) abrupt4xco2 experiment, we explore regional differences in the timing, as opposed to magnitude, of the warming from emissions of CO2. Our analysis reveals a surprisingly high amount of regional diversity in the pace of realization of the warming effect of a CO2 emission, with relatively accelerated warming for areas such as the eastern United States and Central Asia and a relatively long lag between emission and warming effect for Australia and Amazonia. Figure 1 shows the ratio of the ensemble median rate of warming in the first decade after a change in CO2 concentration to the rate of warming for the remainder of the first century. Because estimates of social cost of carbon implicitly assume similar timing of warming for all regions, the observed effects have important implications for climate policy.

  18. Tree-core records of CO2 emissions at three western USA volcanoes

    NASA Astrophysics Data System (ADS)

    Evans, W.; McGeehin, J. P.; King, J.; Mangan, M.

    2012-12-01

    Emissions of magmatic CO2 at quiescent volcanoes are often large enough to cause local 14C depletion in atmospheric CO2 relative to normal ambient values. This 14C-depleted CO2 is fixed by vegetation, including trees, which preserve a record of the depletion in the cellulose of their annual growth rings. We have examined this record by analyzing tree cores collected at Mammoth Mountain, Yellowstone, and Lassen volcanoes as a way to reconstruct the history of gas emission strength. At Mammoth Mountain, tree-core records from an area of cold, diffuse degassing near Horseshoe Lake show 14C depletions up to 16% and indicate peaks in emission strength in the early 1990s and in the last two years. Both peaks closely follow notable seismic swarms thought to reflect intrusion of magmatic fluids at depth. At Yellowstone, 14C depletions spiked in the 1970s at two thermal areas, Mud Volcano and Terrace, reaching 26% and 8.4%, respectively. These spikes correlate with seismic events, but the relation is more complex than at Mammoth Mountain, with some major seismic swarms not obviously linked to increased emissions. Depletions in 14C are detectable at a number of other thermal sites at Yellowstone, offering the possibility to study areal variability in CO2 emissions. Tree cores from two thermal sites (Devil's Kitchen and Bumpass Hell) and a non-thermal feature at Lassen show little or no 14C depletion (3.9% maximum), even though tree locations appear to be favorable for capturing emitted CO2. Emission strength at these sites is apparently too low to affect the 14C of CO2 at canopy height, a critical limitation to the use of the tree-core method. Other drawbacks to the method include sizeable sample processing costs and the need for precise dendrochronology to ensure that the growth rings analyzed correspond to specific years of known seismic or volcanic unrest. On the positive side, the method affords the opportunity to develop long-term (centuries) records of emission

  19. Future CO2 Emissions and Climate Change from Existing Energy Infrastructure

    NASA Astrophysics Data System (ADS)

    Davis, S. J.; Caldeira, K.; Matthews, D.

    2010-12-01

    If current greenhouse gas (GHG) concentrations remain constant, the world would be committed to several centuries of increasing global mean temperatures and sea level rise. By contrast, near elimination of anthropogenic CO2 emissions would be required to produce diminishing GHG concentrations consistent with stabilization of mean temperatures. Yet long-lived energy and transportation infrastructure now operating can be expected to contribute substantial CO2 emissions over the next 50 years. Barring widespread retrofitting of existing power plants with carbon capture and storage (CCS) technologies or the early decommissioning of serviceable infrastructure, these “committed emissions” represent infrastructural inertia which may be the primary contributor to total future warming commitment. With respect to GHG emissions, infrastructural inertia may be thought of as having two important and overlapping components: (i) infrastructure that directly releases GHGs to the atmosphere, and (ii) infrastructure that contributes to the continued production of devices that emit GHGs to the atmosphere. For example, the interstate highway and refueling infrastructure in the United States facilitates continued production of gasoline-powered automobiles. Here, we focus only on the warming commitment from infrastructure that directly releases CO2 to the atmosphere. Essentially, we answer the question: What if no additional CO2-emitting devices (e.g., power plants, motor vehicles) were built, but all the existing CO2-emitting devices were allowed to live out their normal lifetimes? What CO2 levels and global mean temperatures would we attain? Of course, the actual lifetime of devices may be strongly influenced by economic and policy constraints. For instance, a ban on new CO2-emitting devices would create tremendous incentive to prolong the lifetime of existing devices. Thus, our scenarios are not realistic, but offer a means of gauging the threat of climate change from existing

  20. Updating soil CO2 emission experiments to assess climate change effects and extracellular soil respiration

    NASA Astrophysics Data System (ADS)

    Vidal Vazquez, Eva; Paz Ferreiro, Jorge

    2014-05-01

    Experimental work is an essential component in training future soil scientists. Soil CO2 emission is a key issue because of the potential impacts of this process on the greenhouse effect. The amount of organic carbon stored in soils worldwide is about 1600 gigatons (Gt) compared to 750 Gt in the atmosphere mostly in the form of CO2. Thus, if soil respiration increased slightly so that just 10% of the soil carbon pool was converted to CO2, atmospheric CO2 concentrations in the atmosphere could increase by one-fifth. General circulation model predictions indicate atmosphere warming between 2 and 5°C (IPCC 2007) and precipitation changes ranging from about -15 to +30%. Traditionally, release of CO2 was thought to occur only in an intracellular environment; however, recently CO2 emissions have been in irradiated soil, in the absence of microorganisms (Maire et al., 2013). Moreover, soil plays a role in the stabilization of respiration enzymes promoting CO2 release after microorganism death. Here, we propose to improve CO2 emission experiments commonly used in soil biology to investigate: 1) effects of climatic factors on soil CO2 emissions, and 2) rates of extracellular respiration in soils and how these rates are affected by environmental factors. Experiment designed to assess the effect of climate change can be conducted either in field conditions under different ecosystems (forest, grassland, cropland) or in a greenhouse using simple soil chambers. The interactions of climate change in CO2 emissions are investigated using climate-manipulation experiment that can be adapted to field or greenhouse conditions (e.g. Mc Daniel et al., 2013). The experimental design includes a control plot (without soil temperature and rain manipulation) a warming treatment as well as wetting and/or drying treatments. Plots are warmed to the target temperature by procedures such as infrared heaters (field) or radiant cable (greenhouse). To analyze extracellular respiration, rates of CO2

  1. Multivariate regulation of soil CO2 and N2 O pulse emissions from agricultural soils.

    PubMed

    Liang, Liyin L; Grantz, David A; Jenerette, G Darrel

    2016-03-01

    Climate and land-use models project increasing occurrence of high temperature and water deficit in both agricultural production systems and terrestrial ecosystems. Episodic soil wetting and subsequent drying may increase the occurrence and magnitude of pulsed biogeochemical activity, affecting carbon (C) and nitrogen (N) cycles and influencing greenhouse gas (GHG) emissions. In this study, we provide the first data to explore the responses of carbon dioxide (CO2 ) and nitrous oxide (N2 O) fluxes to (i) temperature, (ii) soil water content as percent water holding capacity (%WHC), (iii) substrate availability throughout, and (iv) multiple soil drying and rewetting (DW) events. Each of these factors and their interactions exerted effects on GHG emissions over a range of four (CO2 ) and six (N2 O) orders of magnitude. Maximal CO2 and N2 O fluxes were observed in environments combining intermediate %WHC, elevated temperature, and sufficient substrate availability. Amendments of C and N and their interactions significantly affected CO2 and N2 O fluxes and altered their temperature sensitivities (Q10 ) over successive DW cycles. C amendments significantly enhanced CO2 flux, reduced N2 O flux, and decreased the Q10 of both. N amendments had no effect on CO2 flux and increased N2 O flux, while significantly depressing the Q10 for CO2 , and having no effect on the Q10 for N2 O. The dynamics across DW cycles could be attributed to changes in soil microbial communities as the different responses to wetting events in specific group of microorganisms, to the altered substrate availabilities, or to both. The complex interactions among parameters influencing trace gas fluxes should be incorporated into next generation earth system models to improve estimation of GHG emissions. PMID:26470015

  2. High Performance Fe Porphyrin/Ionic Liquid Co-catalyst for Electrochemical CO2 Reduction.

    PubMed

    Choi, Jaecheol; Benedetti, Tania M; Jalili, Rouhollah; Walker, Ashley; Wallace, Gordon G; Officer, David L

    2016-09-26

    The efficient and selective catalytic reduction of CO2 is a highly promising process for both of the storage of renewable energy as well as the production of valuable chemical feedstocks. In this work, we show that the addition of an ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, in an aprotic electrolyte containing a proton source and FeTPP, promotes the in situ formation of the [Fe(0) TPP](2-) homogeneous catalyst at a less negative potential, resulting in lower overpotentials for the CO2 reduction (670 mV) and increased kinetics of electron transfer. This co-catalysis exhibits high Faradaic efficiency for CO production (93 %) and turnover number (2 740 000 after 4 hour electrolysis), with a four-fold increase in turnover frequency (TOF) when compared with the standard system without the ionic liquid.

  3. High Performance Fe Porphyrin/Ionic Liquid Co-catalyst for Electrochemical CO2 Reduction.

    PubMed

    Choi, Jaecheol; Benedetti, Tania M; Jalili, Rouhollah; Walker, Ashley; Wallace, Gordon G; Officer, David L

    2016-09-26

    The efficient and selective catalytic reduction of CO2 is a highly promising process for both of the storage of renewable energy as well as the production of valuable chemical feedstocks. In this work, we show that the addition of an ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, in an aprotic electrolyte containing a proton source and FeTPP, promotes the in situ formation of the [Fe(0) TPP](2-) homogeneous catalyst at a less negative potential, resulting in lower overpotentials for the CO2 reduction (670 mV) and increased kinetics of electron transfer. This co-catalysis exhibits high Faradaic efficiency for CO production (93 %) and turnover number (2 740 000 after 4 hour electrolysis), with a four-fold increase in turnover frequency (TOF) when compared with the standard system without the ionic liquid. PMID:27464300

  4. Visible-light-driven CO2 reduction with carbon nitride: enhancing the activity of ruthenium catalysts.

    PubMed

    Kuriki, Ryo; Sekizawa, Keita; Ishitani, Osamu; Maeda, Kazuhiko

    2015-02-16

    A heterogeneous photocatalyst system that consists of a ruthenium complex and carbon nitride (C3N4), which act as the catalytic and light-harvesting units, respectively, was developed for the reduction of CO2 into formic acid. Promoting the injection of electrons from C3N4 into the ruthenium unit as well as strengthening the electronic interactions between the two units enhanced its activity. The use of a suitable solvent further improved the performance, resulting in a turnover number of greater than 1000 and an apparent quantum yield of 5.7% at 400 nm. These are the best values that have been reported for heterogeneous photocatalysts for CO2 reduction under visible-light irradiation to date.

  5. Mapping CO2 emission in highly urbanized region using standardized microbial respiration approach

    NASA Astrophysics Data System (ADS)

    Vasenev, V. I.; Stoorvogel, J. J.; Ananyeva, N. D.

    2012-12-01

    Urbanization is a major recent land-use change pathway. Land conversion to urban has a tremendous and still unclear effect on soil cover and functions. Urban soil can act as a carbon source, although its potential for CO2 emission is also very high. The main challenge in analysis and mapping soil organic carbon (SOC) in urban environment is its high spatial heterogeneity and temporal dynamics. The urban environment provides a number of specific features and processes that influence soil formation and functioning and results in a unique spatial variability of carbon stocks and fluxes at short distance. Soil sealing, functional zoning, settlement age and size are the predominant factors, distinguishing heterogeneity of urban soil carbon. The combination of these factors creates a great amount of contrast clusters with abrupt borders, which is very difficult to consider in regional assessment and mapping of SOC stocks and soil CO2 emission. Most of the existing approaches to measure CO2 emission in field conditions (eddy-covariance, soil chambers) are very sensitive to soil moisture and temperature conditions. They require long-term sampling set during the season in order to obtain relevant results. This makes them inapplicable for the analysis of CO2 emission spatial variability at the regional scale. Soil respiration (SR) measurement in standardized lab conditions enables to overcome this difficulty. SR is predominant outgoing carbon flux, including autotrophic respiration of plant roots and heterotrophic respiration of soil microorganisms. Microbiota is responsible for 50-80% of total soil carbon outflow. Microbial respiration (MR) approach provides an integral CO2 emission results, characterizing microbe CO2 production in optimal conditions and thus independent from initial difference in soil temperature and moisture. The current study aimed to combine digital soil mapping (DSM) techniques with standardized microbial respiration approach in order to analyse and

  6. Effectiveness of US state policies in reducing CO2 emissions from power plants

    NASA Astrophysics Data System (ADS)

    Grant, Don; Bergstrand, Kelly; Running, Katrina

    2014-11-01

    President Obama's landmark initiative to reduce the CO2 emissions of existing power plants, the nation's largest source of greenhouse gas (GHG) pollutants, depends heavily on states and their ability to devise policies that meet the goals set by the Environmental Protection Agency (EPA). Under the EPA's proposed Clean Power Plan, states will be responsible for cutting power plants' carbon pollution 30% from 2005 levels by 2030. States have already adopted several policies to reduce the electricity sector's climate impact. Some of these policies focus on reducing power plants' CO2 emissions, and others address this outcome in a more roundabout fashion by encouraging energy efficiency and renewable energy. However, it remains unclear which, if any, of these direct and indirect strategies actually mitigate plants' emissions because scholars have yet to test their effects using plant-level emission data. Here we use a newly released data source to determine whether states' policies significantly shape individual power plants' CO2 emissions. Findings reveal that certain types of direct strategy (emission caps and GHG targets) and indirect ones (public benefit funds and electric decoupling) lower plants' emissions and thus are viable building blocks of a federal climate regime.

  7. High resolution fossil fuel combustion CO2 emission fluxes for the United States.

    PubMed

    Gurney, Kevin R; Mendoza, Daniel L; Zhou, Yuyu; Fischer, Marc L; Miller, Chris C; Geethakumar, Sarath; de la Rue du Can, Stephane

    2009-07-15

    Quantification of fossil fuel CO2 emissions at fine space and time resolution is emerging as a critical need in carbon cycle and climate change research. As atmospheric CO2 measurements expand with the advent of a dedicated remote sensing platform and denser in situ measurements, the ability to close the carbon budget at spatial scales of approximately 100 km2 and daily time scales requires fossil fuel CO2 inventories at commensurate resolution. Additionally, the growing interest in U.S. climate change policy measures are best served by emissions that are tied to the driving processes in space and time. Here we introduce a high resolution data product (the "Vulcan" inventory: www.purdue.edu/eas/carbon/vulcan/) that has quantified fossil fuel CO2 emissions for the contiguous U.S. at spatial scales less than 100 km2 and temporal scales as small as hours. This data product completed for the year 2002, includes detail on combustion technology and 48 fuel types through all sectors of the U.S. economy. The Vulcan inventory is built from the decades of local/regional air pollution monitoring and complements these data with census, traffic, and digital road data sets. The Vulcan inventory shows excellent agreement with national-level Department of Energy inventories, despite the different approach taken by the DOE to quantify U.S. fossil fuel CO2 emissions. Comparison to the global 1degree x 1 degree fossil fuel CO2 inventory, used widely by the carbon cycle and climate change community prior to the construction of the Vulcan inventory, highlights the space/time biases inherent in the population-based approach.

  8. High resolution fossil fuel combustion CO2 emission fluxes for the United States.

    PubMed

    Gurney, Kevin R; Mendoza, Daniel L; Zhou, Yuyu; Fischer, Marc L; Miller, Chris C; Geethakumar, Sarath; de la Rue du Can, Stephane

    2009-07-15

    Quantification of fossil fuel CO2 emissions at fine space and time resolution is emerging as a critical need in carbon cycle and climate change research. As atmospheric CO2 measurements expand with the advent of a dedicated remote sensing platform and denser in situ measurements, the ability to close the carbon budget at spatial scales of approximately 100 km2 and daily time scales requires fossil fuel CO2 inventories at commensurate resolution. Additionally, the growing interest in U.S. climate change policy measures are best served by emissions that are tied to the driving processes in space and time. Here we introduce a high resolution data product (the "Vulcan" inventory: www.purdue.edu/eas/carbon/vulcan/) that has quantified fossil fuel CO2 emissions for the contiguous U.S. at spatial scales less than 100 km2 and temporal scales as small as hours. This data product completed for the year 2002, includes detail on combustion technology and 48 fuel types through all sectors of the U.S. economy. The Vulcan inventory is built from the decades of local/regional air pollution monitoring and complements these data with census, traffic, and digital road data sets. The Vulcan inventory shows excellent agreement with national-level Department of Energy inventories, despite the different approach taken by the DOE to quantify U.S. fossil fuel CO2 emissions. Comparison to the global 1degree x 1 degree fossil fuel CO2 inventory, used widely by the carbon cycle and climate change community prior to the construction of the Vulcan inventory, highlights the space/time biases inherent in the population-based approach. PMID:19708393

  9. Experimental and Numerical Modelling of CO2 Atmospheric Dispersion in Hazardous Gas Emission Sites.

    NASA Astrophysics Data System (ADS)

    Gasparini, A.; sainz Gracia, A. S.; Grandia, F.; Bruno, J.

    2015-12-01

    Under stable atmospheric conditions and/or in presence of topographic depressions, CO2 concentrations can reach high values resulting in lethal effect to living organisms. The distribution of denser than air gases released from the underground is governed by gravity, turbulence and dispersion. Once emitted, the gas distribution is initially driven by buoyancy and a gas cloud accumulates on the ground (gravitational phase); with time the density gradient becomes less important due to dispersion or mixing and gas distribution is mainly governed by wind and atmospheric turbulence (passive dispersion phase). Natural analogues provide evidences of the impact of CO2 leakage. Dangerous CO2 concentration in atmosphere related to underground emission have been occasionally reported although the conditions favouring the persistence of such a concentration are barely studied.In this work, the dynamics of CO2 in the atmosphere after ground emission is assessed to quantify their potential risk. Two approaches have been followed: (1) direct measurement of air concentration in a natural emission site, where formation of a "CO2 lake" is common and (2) numerical atmospheric modelling. Two sites with different morphology were studied: (a) the Cañada Real site, a flat terrain in the Volcanic Field of Campo de Calatrava (Spain); (b) the Solforata di Pomezia site, a rough terrain in the Alban Hills Volcanic Region (Italy). The comparison between field data and model calculations reveal that numerical dispersion models are capable of predicting the formation of CO2 accumulation over the ground as a consequence of underground gas emission. Therefore, atmospheric modelling could be included as a valuable methodology in the risk assessment of leakage in natural degassing systems and in CCS projects. Conclusions from this work provide clues on whether leakage may be a real risk for humans and under which conditions this risk needs to be included in the risk assessment.

  10. On the relation between soil CO2 emission and aspects of soil diffuse reflectance

    NASA Astrophysics Data System (ADS)

    Bahia, A. S. R. S.; Marques, J., Jr.; La Scala, N., Jr.; Panosso, A. R.; Barron, V.; Torrent, J.

    2012-04-01

    Carbon dioxide (CO2) is the greenhouse gas that has shown the most significant increases on its atmospheric concentration during the last years. According to the Intergovernmental Panel on Climate Change (IPCC), increasing of CO2 atmospheric concentration is the main cause of global warming, corresponding to around 60% of the enhanced greenhouse effect. In the agricultural sector, 22% of CO2 emissions could be related to land use and land use change, such as deforestation. The process of soil CO2 emissions, known as soil respiration, is the second largest source of emissions of CO2 into the atmosphere, following only to burning of fossil fuels. It is known that this process of soil carbon loss to the atmosphere is the result of microbial activity (chemical oxidation) and roots respiration. These processes, in turn, are influenced by several soil properties, which provide spatial and temporal variability to soil CO2 emission. Therefore, the objective of this study was to investigate the relationship between CO2 emissions and some properties of a tropical Brazilian Oxisol used for the cultivation of sugarcane. Soil samples were collected at points of intersection of an irregularly gridded, georeferenced with minimum distances of 0,5 m in depth from 0,00 to 0,20 m, covering a total area of 50 x 50 m, totaling 89 points. Those points were measured soil respiration with two portable systems manufactured by LI-8100 LI-COR Company. The spectra were recorded every 0.5 nm in the wavelength range from 380 to 730 nm in a spectrophotometer Lambda 950 UV/VIS/NIR PerkinElmer equipped with an integrating sphere. It was observed that some aspects of the diffuse reflectance spectroscopy were linear correlated with the values of soil respiration measured in the field. The content of the iron oxides hematite and goethite and iron content of the clay, dithionite and oxalate showed a directly proportional relation to CO2 emission, indicating a complex link between the clay minerals

  11. Bias present in US federal agency power plant CO2 emissions data and implications for the US clean power plan

    NASA Astrophysics Data System (ADS)

    Gurney, K. R.; Huang, J.; Coltin, K.

    2016-06-01

    Power plants constitute roughly 40% of carbon dioxide (CO2) emissions in the United States. Climate change science, air pollution regulation, and potential carbon trading policies rely on accurate, unbiased quantification of these large point sources. Two US federal agencies—the Department of Energy and the Environmental Protection Agency—tabulate the emissions from US power plants using two different methodological approaches. We have analyzed those two data sets and have found that when averaged over all US facilities, the median percentage difference is less than 3%. However, this small difference masks large, non-Gaussian, positive and negative differences at individual facilities. For example, over the 2001–2009 time period, nearly one-half of the facilities have monthly emission differences that exceed roughly ±6% and one-fifth exceed roughly ±13%. It is currently not possible to assess whether one, or both, of the datasets examined here are responsible for the emissions difference. Differences this large at the individual facility level raise concerns regarding the operationalization of policy within the United States such as the recently announced Clean Power Plan. This policy relies on the achievement of state-level CO2 emission rate targets. When examined at the state-level we find that one-third of the states have differences that exceed 10% of their assigned reduction amount. Such levels of uncertainty raise concerns about the ability of individual states to accurately quantify emission rates in order to meet the regulatory targets.

  12. Bias present in US federal agency power plant CO2 emissions data and implications for the US clean power plan

    NASA Astrophysics Data System (ADS)

    Gurney, K. R.; Huang, J.; Coltin, K.

    2016-06-01

    Power plants constitute roughly 40% of carbon dioxide (CO2) emissions in the United States. Climate change science, air pollution regulation, and potential carbon trading policies rely on accurate, unbiased quantification of these large point sources. Two US federal agencies—the Department of Energy and the Environmental Protection Agency—tabulate the emissions from US power plants using two different methodological approaches. We have analyzed those two data sets and have found that when averaged over all US facilities, the median percentage difference is less than 3%. However, this small difference masks large, non-Gaussian, positive and negative differences at individual facilities. For example, over the 2001-2009 time period, nearly one-half of the facilities have monthly emission differences that exceed roughly ±6% and one-fifth exceed roughly ±13%. It is currently not possible to assess whether one, or both, of the datasets examined here are responsible for the emissions difference. Differences this large at the individual facility level raise concerns regarding the operationalization of policy within the United States such as the recently announced Clean Power Plan. This policy relies on the achievement of state-level CO2 emission rate targets. When examined at the state-level we find that one-third of the states have differences that exceed 10% of their assigned reduction amount. Such levels of uncertainty raise concerns about the ability of individual states to accurately quantify emission rates in order to meet the regulatory targets.

  13. Delay-feedback control strategy for reducing CO2 emission of traffic flow system

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Dong; Zhu, Wen-Xing

    2015-06-01

    To study the signal control strategy for reducing traffic emission theoretically, we first presented a kind of discrete traffic flow model with relative speed term based on traditional coupled map car-following model. In the model, the relative speed difference between two successive running cars is incorporated into following vehicle's acceleration running equation. Then we analyzed its stability condition with discrete control system stability theory. Third, we designed a delay-feedback controller to suppress traffic jam and decrease traffic emission based on modern controller theory. Last, numerical simulations are made to support our theoretical results, including the comparison of models' stability analysis, the influence of model type and signal control on CO2 emissions. The results show that the temporal behavior of our model is superior to other models, and the traffic signal controller has good effect on traffic jam suppression and traffic CO2 emission, which fully supports the theoretical conclusions.

  14. The Impact of CO2 Emission Contraints on U.S. Electric Sector Water Use

    EPA Science Inventory

    The U.S. electric power sector’s reliance on water makes it vulnerable to increased water temperature and drought resulting from climate change. Here we analyze how constraints on U.S. energy system carbon dioxide (CO2) emissions could affect water withdrawal and consumpti...

  15. Passenger transport and CO 2 emissions: What does the French transport survey tell us?

    NASA Astrophysics Data System (ADS)

    Nicolas, Jean-Pierre; David, Damien

    The aim of this article is to analyse CO 2 emissions caused by passenger transport in France: which socio-demographic groups travel, for what kinds of journey (local or long distance), how and why? Research focusing on the analysis of individual travel can improve the understanding of CO 2 emissions by identifying upstream socio-economic factors, and also enable a better assessment of the potential social impact of measures introduced to limit greenhouse gases due to transport. Calculations are based on the latest French national transport survey (1994). Distances covered and CO 2 emissions were estimated for each journey and for each surveyed individual. A socio-demographic characteristic typology was built and results were obtained through this analysis. If equity and accessibility issues are to be taken into account, planned policies cannot be of the same type if linked to mobility segments. An environmental tax system to limit CO 2 emission increases appears appropriate for long-distance trips. Results are more varied for local journeys, which are often more of a necessity. Nevertheless, income brackets, and measures concerning urban planning or the growth of new car fleets, seem more pertinent.

  16. Increased soil emissions of potent greenhouse gases under increased atmospheric CO2.

    PubMed

    van Groenigen, Kees Jan; Osenberg, Craig W; Hungate, Bruce A

    2011-07-13

    Increasing concentrations of atmospheric carbon dioxide (CO(2)) can affect biotic and abiotic conditions in soil, such as microbial activity and water content. In turn, these changes might be expected to alter the production and consumption of the important greenhouse gases nitrous oxide (N(2)O) and methane (CH(4)) (refs 2, 3). However, studies on fluxes of N(2)O and CH(4) from soil under increased atmospheric CO(2) have not been quantitatively synthesized. Here we show, using meta-analysis, that increased CO(2) (ranging from 463 to 780 parts per million by volume) stimulates both N(2)O emissions from upland soils and CH(4) emissions from rice paddies and natural wetlands. Because enhanced greenhouse-gas emissions add to the radiative forcing of terrestrial ecosystems, these emissions are expected to negate at least 16.6 per cent of the climate change mitigation potential previously predicted from an increase in the terrestrial carbon sink under increased atmospheric CO(2) concentrations. Our results therefore suggest that the capacity of land ecosystems to slow climate warming has been overestimated.

  17. Determinants of overwinter variation in CO2 emission from natural landscapes

    NASA Astrophysics Data System (ADS)

    Graham, L. M.; Risk, D. A.; Natali, S.; Nickerson, N. R.

    2013-12-01

    the model must be higher than the diffusivity of CO2 in free air, at magnitudes approaching those of a turbulent free atmosphere, in order to induce the variability and quick step changes in concentration seen in natural landscapes. This confirms the expectation that advective transport, such as wind, regulates wintertime CO2 efflux through a soil-snow profile. Overall, this study helps to show that snowpack, soil diffusivity, and CO2 production all play a role in regulating CO2 efflux through a soil-snow profile. Winter gas transport regimes are complex, and vary dynamically in accordance with snowpack and climatic characteristics. Monitoring tools like FD that measure only the diffusive efflux component may in some cases significantly underestimate total emissions.

  18. Dissecting the steps of CO2 reduction: 2. The interaction of CO and CO2 with Pd/γ-Al2O3: an in situ FTIR study

    SciTech Connect

    Szanyi, Janos; Kwak, Ja Hun

    2014-08-07

    Alumina supported Pd catalysts with metal loadings of 0.5, 2.5 and 10 wt% were investigated by in situ FTIR spectroscopy in order to understand the nature of adsorbed species formed during their exposure to CO2 and CO. Exposing the annealed samples to CO2 at 295 K resulted in the formation of alumina support-bound surface species only: linear adsorbed CO2, bidentate carbonates and bicarbonates. Room temperature exposure of all three samples to CO produced IR features characteristic of both ionic and metallic Pd, as well as bands we observed upon CO2 adsorption (alumina support-bound species). Low temperature (100 K) adsorption of CO on the three samples provided information about the state of Pd after oxidation and reduction. Oxidized samples contained exclusively ionic Pd, while mostly metallic Pd was present in the reduced samples. Subsequent annealing of the CO-saturated samples revealed the facile (low temperature) reduction of PdOx species by adsorbed CO. This process was evidenced by the variations in IR bands characteristic of ionic and metallic Pd-bound CO, as well as by the appearance of IR bands associated with CO2 adsorption as a function of annealing temperature. Samples containing oxidized Pd species (oxidized, annealed or reduced) always produced CO2 upon their exposure to CO, while CO2-related surface entities were observed on samples having only fully reduced (metallic) Pd. Acknowledgements: The catalyst preparation was supported by a Laboratory Directed Research and Development (LDRD) project. This work was supported by the US Department of Energy Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy. JHK also acknowledges the support of this work by the 2013 Research Fund of UNIST (Ulsan National Institute of Science and Technology, Ulsan, Korea).

  19. Storage of Renewable Energy by Reduction of CO2 with Hydrogen.

    PubMed

    Züttel, Andreas; Mauron, Philippe; Kato, Shunsuke; Callini, Elsa; Holzer, Marco; Huang, Jianmei

    2015-01-01

    The main difference between the past energy economy during the industrialization period which was mainly based on mining of fossil fuels, e.g. coal, oil and methane and the future energy economy based on renewable energy is the requirement for storage of the energy fluxes. Renewable energy, except biomass, appears in time- and location-dependent energy fluxes as heat or electricity upon conversion. Storage and transport of energy requires a high energy density and has to be realized in a closed materials cycle. The hydrogen cycle, i.e. production of hydrogen from water by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines, is a closed cycle. However, the hydrogen density in a storage system is limited to 20 mass% and 150 kg/m(3) which limits the energy density to about half of the energy density in fossil fuels. Introducing CO(2) into the cycle and storing hydrogen by the reduction of CO(2) to hydrocarbons allows renewable energy to be converted into synthetic fuels with the same energy density as fossil fuels. The resulting cycle is a closed cycle (CO(2) neutral) if CO(2) is extracted from the atmosphere. Today's technology allows CO(2) to be reduced either by the Sabatier reaction to methane, by the reversed water gas shift reaction to CO and further reduction of CO by the Fischer-Tropsch synthesis (FTS) to hydrocarbons or over methanol to gasoline. The overall process can only be realized on a very large scale, because the large number of by-products of FTS requires the use of a refinery. Therefore, a well-controlled reaction to a specific product is required for the efficient conversion of renewable energy (electricity) into an easy to store liquid hydrocarbon (fuel). In order to realize a closed hydrocarbon cycle the two major challenges are to extract CO(2) from the atmosphere close to the thermodynamic limit and to reduce CO(2) with hydrogen in a controlled reaction to a specific hydrocarbon. Nanomaterials with

  20. Storage of Renewable Energy by Reduction of CO2 with Hydrogen.

    PubMed

    Züttel, Andreas; Mauron, Philippe; Kato, Shunsuke; Callini, Elsa; Holzer, Marco; Huang, Jianmei

    2015-01-01

    The main difference between the past energy economy during the industrialization period which was mainly based on mining of fossil fuels, e.g. coal, oil and methane and the future energy economy based on renewable energy is the requirement for storage of the energy fluxes. Renewable energy, except biomass, appears in time- and location-dependent energy fluxes as heat or electricity upon conversion. Storage and transport of energy requires a high energy density and has to be realized in a closed materials cycle. The hydrogen cycle, i.e. production of hydrogen from water by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines, is a closed cycle. However, the hydrogen density in a storage system is limited to 20 mass% and 150 kg/m(3) which limits the energy density to about half of the energy density in fossil fuels. Introducing CO(2) into the cycle and storing hydrogen by the reduction of CO(2) to hydrocarbons allows renewable energy to be converted into synthetic fuels with the same energy density as fossil fuels. The resulting cycle is a closed cycle (CO(2) neutral) if CO(2) is extracted from the atmosphere. Today's technology allows CO(2) to be reduced either by the Sabatier reaction to methane, by the reversed water gas shift reaction to CO and further reduction of CO by the Fischer-Tropsch synthesis (FTS) to hydrocarbons or over methanol to gasoline. The overall process can only be realized on a very large scale, because the large number of by-products of FTS requires the use of a refinery. Therefore, a well-controlled reaction to a specific product is required for the efficient conversion of renewable energy (electricity) into an easy to store liquid hydrocarbon (fuel). In order to realize a closed hydrocarbon cycle the two major challenges are to extract CO(2) from the atmosphere close to the thermodynamic limit and to reduce CO(2) with hydrogen in a controlled reaction to a specific hydrocarbon. Nanomaterials with

  1. Visible light plasmonic heating of Au-ZnO for the catalytic reduction of CO2

    DOE PAGES

    Wang, Congjun; Ranasingha, Oshadha; Natesakhawat, Sittichai; Ohodnicki, Paul R.; Andio, Mark; Lewis, James P.; Matranga, Christopher

    2013-01-01

    Plasmonic excitation of Au nanoparticles attached to the surface of ZnO catalysts using low power 532 nm laser illumination leads to significant heating of the catalyst and the conversion of CO2 and H2 reactants to CH4 and CO products. Temperature-calibrated Raman spectra of ZnO phonons show that intensity-dependent plasmonic excitation can controllably heat Au–ZnO from 30 to ~600 °C and simultaneously tune the CH4 : CO product ratio. The laser induced heating and resulting CH4 : CO product distribution agrees well with predictions from thermodynamic models and temperature-programmed reaction experiments indicating that the reaction is a thermally driven process resultingmore » from the plasmonic heating of the Au-ZnO. The apparent quantum yield for CO2 conversion under continuous wave (cw) 532 nm laser illumination is 0.030%. The Au-ZnO catalysts are robust and remain active after repeated laser exposure and cycling. The light intensity required to initiate CO2 reduction is low ( ~2.5 x 105 W m-2) and achievable with solar concentrators. Our results illustrate the viability of plasmonic heating approaches for CO2 utilization and other practical thermal catalytic applications.« less

  2. Laboratory Measurement of the CO Cameron Bands and Visible Emissions Following VUV Photodissociation of CO{_2}

    NASA Astrophysics Data System (ADS)

    Kalogerakis, K. S.; Romanescu, C.; Slanger, T. G.; Lee, L. C.; Ahmed, M.; Wilson, K. R.

    2009-06-01

    The CO(a^{3}Π-X^{1}Σ^{+}) Cameron bands are one of the most important emission features in the UV dayglow of the CO{_2} planets, as demonstrated in the case of Mars by the measurements performed by Mariner and Mars Express missions. One of the mechanisms to produce electronically excited CO(a^{3}Π) is photodissociation of CO{_2} at wavelengths shorter than 108 nm. At wavelengths below 100 nm, new CO{_2} photodissociation channels open leading to formation of higher energy triplet states of CO. These states cascade into the lower triplet state by emission in the visible spectral region before radiating in the Cameron system. This two step relaxation pathway was demonstrated by Lee and Judge for the 90-93 nm photodissociation of CO{_2}. We have further investigated this process using the 85-110 nm tunable synchrotron radiation at the Advanced Light Source facility at Lawrence Berkeley Laboratory. The experimental results confirmed that once a triplet state excitation threshold is exceeded, a fraction of the Cameron band emission is accompanied by visible emission. These results indicate that the emission corresponding to the CO(a^'-a, d-a, e-a) triplet bands must be part of the visible Mars / Venus dayglow. The same is true for CO{_2} photoexcitation in cometary atmospheres. This work was supported by the NASA Outer Planets Research Program under grant NNX06AB82G. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. D. L. Judge and L. C. Lee, J. Chem. Phys., 58, 104 (1973)

  3. Geological modelling for investigating CO2 emissions in Florina Basin, Greece

    NASA Astrophysics Data System (ADS)

    Koukouzas, Nikolaos; Tasianas, Alexandros; Gemeni, Vasiliki; Alexopoulos, Dimitrios; Vasilatos, Charalampos

    2015-10-01

    This paper presents an investigation of naturally occurring CO2 emissions from the Florina natural analogue site in Greece. The main objective was to interpret previously collected depth sounding data, convert them into surfaces, and use them as input to develop, for the first time, 3D geological models of the Florina basin. By also locating the extent of the aquifer, the location of the CO2 source, the location of other natural CO2 accumulations, and the points where CO2 reaches the surface, we were able to assess the potential for CO2 leakage. Geological models provided an estimate of the lithological composition of the Florina Basin and allowed us to determine possible directions of groundwater flow and pathways of CO2 flow throughout the basin. Important modelling parameters included the spatial positions of boundaries, faults, and major stratigraphic units (which were subdivided into layers of cells). We used various functions in Petrel software to first construct a structural model describing the main rock boundaries.We then defined a 3D mesh honouring the structural model, and finally we populated each cell in the mesh with geologic properties, such as rock type and relative permeability. According to the models, the thickest deposits are located around Mesochorion village where we estimate that around 1000 m of sediments were deposited above the basement. Initiation of CO2 flow at Florina Basin could have taken place between 6.5 Ma and 1.8 Ma ago. The NESW oriented faults, which acted as fluid flow pathways, are still functioning today, allowing for localised leakage at the surface. CO2 leakage may be spatially variable and episodic in rate. The episodicity can be linked to the timing of Almopia volcanic activity in the area.

  4. A multiresolution random field model for estimating fossil-fuel CO2 emissions

    NASA Astrophysics Data System (ADS)

    Ray, J.; Yadav, V.; Michalak, A. M.; Lee, J.; Lefantzi, S.; VanBloemenWaanders, B.

    2013-12-01

    We present a multiscale random field model (MsRF) that can be used for representing fossil-fuel CO2 (ffCO2) emissions. It is low-dimensional and is meant to be used in atmospheric inversions. The MsRF is constructed using wavelets. In this work, we will demonstrate a synthetic-data inversion aimed at estimating ffCO2 emissions, with 1o x 1o resolution, in the lower 48 states of the US. Measurements from 35 towers will be used. The measurements are constructed using the Vulcan inventory. The MsRF consists of a subset of Haar wavelets that can be defined in a rectangle bounding the US. By subjecting the Vulcan database to wavelet-transforms with a wide choice, the Haar wavelet was found to offer the most compressible representation. The MsRF was constructed by subjecting an image of lights at night to Haar transforms and retaining those with large weights. The lights-at-night image is correlated with ffCO2 inversions and have been used to downscale national ffCO2 aggregates when constructing spatially resolved ffCO2 emission inventories. The MsRF is then used to solve the linear inverse problem that underlies ffCO2 emission estimation. The number of parameters in the MsRF is far too large to be constrained by the measurements and thus we enforce sparsity to regularize the inverse problem. Further, we show that the transport model is only somewhat incoherent with respect to the chosen Haar bases, indicating that sparsification will be insufficient and further regularization using a prior emission model is required. This model is obtained by scaling up the nightlights to match EDGAR emissions. Finally, we present the results of the inversion and show that the resulting inversion mechanism can extract information from the observation to update and improve upon the predictive accuracy of prior model. The density of measurements dominates the accuracy of the inversion. We find that sparsification plays an important role since it removes about 50% of the wavelets in the Ms

  5. Effect of inter-row cultivation on soil CO2 emission in a peach plantation

    NASA Astrophysics Data System (ADS)

    Tóth, E.; Farkas, Cs.; Gelybó, Gy.; Lagzi, I.

    2012-04-01

    We examined the effect of inter-row cultivation on soil CO2 emission in a peach plantation planted in 1991. The soil is Ramann type brown forest soil /Mollic Cambisol/ developed on sandy loam. Every second row in the orchard is covered with undisturbed grass, and every other row is disked (depth: 12-15cm) with a two-three-week frequency. The humus content varies from 1,69% to 2,28% in the upper 20 cm layer, where the sand, loam and clay contents are 58%, 21% and 19 %, respectively. The average annual precipitation total is 570 mm (330 mm for the growing season) at the site. During the vegetation period of 2009 soil CO2 emission measurements were carried out with static chamber method in the differently managed rows. Parallel with CO2 measurements soil volumetric water content and soil temperature were also determined. Soil microbiological properties water-extractable organic carbon (WEOC) and water-extractable nitrogen (WEN) as well as substrate-induced respiration (SIR) were determined from disturbed soil samples collected on the first measurement day. The measured soil physical properties showed that different soil management practices influence soil water content, bulk density and soil temperature as well. Soil water content was higher in the grass covered row on 10 of the 13 measurement days, the difference - which reached 10 v% - was the highest on the warmest days. Soil temperature is also different in case of disked and grass covered rows, found to be lower in the grass covered rows on every measurement days. SIR, WEOC and WEN were all higher in the grass covered row (19.45 μg CO2-C g-1 soil 36.91 μg g-1 soil, 139.36 μg g-1 soil, respectively) than in the disked row (4.88 μg CO2-C g-1 soil 25.43 μg C g-1 soil, 61.25 μg N g-1 soil, respectively) in 2009. Soil CO2 emission also differed between the two rows, grass covered rows produced higher emission in all measurements days without exemption. The difference between CO2 fluxes from the two cultivation

  6. Molybdenum carbide as alternative catalysts to precious metals for highly selective reduction of CO2 to CO.

    PubMed

    Porosoff, Marc D; Yang, Xiaofang; Boscoboinik, J Anibal; Chen, Jingguang G

    2014-06-23

    Rising atmospheric CO2 is expected to have negative effects on the global environment from its role in climate change and ocean acidification. Utilizing CO2 as a feedstock to make valuable chemicals is potentially more desirable than sequestration. A substantial reduction of CO2 levels requires a large-scale CO2 catalytic conversion process, which in turn requires the discovery of low-cost catalysts. Results from the current study demonstrate the feasibility of using the non-precious metal material molybdenum carbide (Mo2C) as an active and selective catalyst for CO2 conversion by H2.

  7. Riverine GHG emissions: one year of CO2, 13CO2 and CH4 flux measurements on Vistula river in Krakow, southern Poland

    NASA Astrophysics Data System (ADS)

    Jasek, Alina; Wachniew, Przemyslaw; Zimnoch, Miroslaw

    2013-04-01

    Terrestrial surface waters are generally considered to be sources of carbon dioxide and methane, because respiration of organic matter via aerobic and anaerobic pathways causes supersaturation of surface waters with respect to CO2 and CH4, respectively. In rivers, these processes are influenced by such anthropogenic factors as changes of land-use, wastewater and alteration of river channels. The research object is Vistula, the largest Polish river. It has the length of 1047 km and annual runoff of 6.2x1010m3. The urban section of Vistula in Krakow receives large amounts of organic matter from highly urbanized catchment and point discharges of urban waste waters within the city limits. The river was sampled regularly at three points: the entrance to the city, the center and the point where Vistula leaves the agglomeration. A floating chamber coupled with Picarro G2101-i analyzer was applied to quantify CO2, 13CO2 and CH4 fluxes leaving the surface of the river. A floating chamber was equipped with sensors to measure air pressure, temperature and humidity inside the chamber and the temperature of water. The chamber was equipped with a set of floats and an anchor. The measurements started in October 2011, and were repeated with approximately monthly frequency. Physicochemical properties of water (temperature, conductivity, pH, CO2 partial pressure over the water surface and alkalinity) were also measured during each measurement campaign. In addition, at each site short-term variability of the measured fluxes was also investigated. Additionally, short-term variability of the measured fluxes of CO2, 13CO2 and CH4 were performed in all three sites. The results indicate that fluxes of CO2 released from the river are comparable with the soil emissions of this gas measured in Krakow area. The δ13CO2 signature of riverine CO2 flux allowed to identify decomposition of C3 organic matter as the major source of this gas. No distinct seasonal variability of the CO2 emission and

  8. Covalent Immobilization of a Molecular Catalyst on Cu2O Photocathodes for CO2 Reduction.

    PubMed

    Schreier, Marcel; Luo, Jingshan; Gao, Peng; Moehl, Thomas; Mayer, Matthew T; Grätzel, Michael

    2016-02-17

    Sunlight-driven CO2 reduction is a promising way to close the anthropogenic carbon cycle. Integrating light harvester and electrocatalyst functions into a single photoelectrode, which converts solar energy and CO2 directly into reduced carbon species, is under extensive investigation. The immobilization of rhenium-containing CO2 reduction catalysts on the surface of a protected Cu2O-based photocathode allows for the design of a photofunctional unit combining the advantages of molecular catalysts with inorganic photoabsorbers. To achieve large current densities, a nanostructured TiO2 scaffold, processed at low temperature, was deposited on the surface of protected Cu2O photocathodes. This led to a 40-fold enhancement of the catalytic photocurrent as compared to planar devices, resulting in the sunlight-driven evolution of CO at large current densities and with high selectivity. Potentiodynamic and spectroelectrochemical measurements point toward a similar mechanism for the catalyst in the bound and unbound form, whereas no significant production of CO was observed from the scaffold in the absence of a molecular catalyst. PMID:26804626

  9. China: Emissions pattern of the world leader in CO2 emissions from fossil fuel consumption and cement production

    SciTech Connect

    Gregg, J; Andres, Robert Joseph; Marland, Gregg

    2008-01-01

    Release of carbon dioxide (CO2) from fossil fuel combustion and cement manufacture is the primary anthropogenic driver of climate change. Our best estimate is that China became the largest national source of CO2 emissions during 2006. Previously, the United States (US) had occupied that position. However, the annual emission rate in the US has remained relatively stable between 2001-2006 while the emission rate in China has more than doubled, apparently eclipsing that of the US in late 2006. Here we present the seasonal and spatial pattern of CO2 emissions in China, as well as the sectoral breakdown of emissions. Though our best point estimate places China in the lead position in terms of CO2 emissions, we qualify this statement in a discussion of the uncertainty in the underlying data (3-5% for the US; 15-20% for China). Finally, we comment briefly on the implications of China's new position with respect to international agreements to mitigate climate change.

  10. Effects of population and affluence on CO2emissions

    PubMed Central

    Dietz, Thomas; Rosa, Eugene A.

    1997-01-01

    We developed a stochastic version of the Impact = Population·Affluence·Technology (IPAT) model to estimate the effects of population, affluence, and technology on national CO2 emissions. Our results suggest that, for population, there are diseconomies of scale for the largest nations that are not consistent with the assumption of direct proportionality (log–linear effects) common to most previous research. In contrast, the effects of affluence on CO2 emissions appear to reach a maximum at about $10,000 in per- capita gross domestic product and to decline at higher levels of affluence. These results confirm the general value of the IPAT model as a starting point for understanding the anthropogenic driving forces of global change and suggest that population and economic growth anticipated over the next decade will exacerbate greenhouse gas emissions. PMID:8990181

  11. Enhanced visible light emission from Co 2+ doped ZnS nanoparticles

    NASA Astrophysics Data System (ADS)

    Sarkar, R.; Tiwary, C. S.; Kumbhakar, P.; Mitra, A. K.

    2009-11-01

    ZnS nanoparticles with Co 2+ doping have been prepared at room temperature through a soft chemical route, namely the chemical co-precipitation method. The nanostructures of the prepared nanoparticles have been analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected-area electron diffraction (SAED), and UV-vis spectrophotometer. The sizes of as prepared nanoparticles are found to be in 1-4 nm range. Room-temperature photoluminescence (PL) spectrum of the undoped sample exhibits emission in the blue region with multiple peaks under UV excitation. On the other hand, in the Co 2+ doped ZnS samples enhanced visible light emissions with emission intensities of ~35 times larger than that of the undoped sample are observed under the same UV excitation wavelength of 280 nm.

  12. Industrial sources of CO 2 emissions in Poland in the light of underground storage possibilities

    NASA Astrophysics Data System (ADS)

    Tarkowski, Radosław

    2005-07-01

    Industrial sectors responsible for large part of CO 2 emissions in Poland are characterized from the point of view of possibilities of sequestration of this gas by underground storage. On the basis of official statistics and data obtained from local administration and individual plants, attempt was made to evaluate the magnitude of emissions from selected categories, sub-categories and sectors of the industry (in accordance with methodology of IPCC), concentration of CO 2 in combustion gases and those emitted by industry, and to identify major point sources of emission of this gas in Poland. A special attention was paid to those sectors of industry that may be the first to act as a source of carbon dioxide for sequestration by underground storage in the nearest future. To cite this article: R. Tarkowski, C. R. Geoscience 337 (2005).

  13. An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements

    NASA Astrophysics Data System (ADS)

    Bréon, F. M.; Broquet, G.; Puygrenier, V.; Chevallier, F.; Xueref-Remy, I.; Ramonet, M.; Dieudonné, E.; Lopez, M.; Schmidt, M.; Perrussel, O.; Ciais, P.

    2015-02-01

    Atmospheric concentration measurements are used to adjust the daily to monthly budget of fossil fuel CO2 emissions of the Paris urban area from the prior estimates established by the Airparif local air quality agency. Five atmospheric monitoring sites are available, including one at the top of the Eiffel Tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model. The inversion adjusts prior knowledge about the anthropogenic and biogenic CO2 fluxes from the Airparif inventory and an ecosystem model, respectively, with corrections at a temporal resolution of 6 h, while keeping the spatial distribution from the emission inventory. These corrections are based on assumptions regarding the temporal autocorrelation of prior emissions uncertainties within the daily cycle, and from day to day. The comparison of the measurements against the atmospheric transport simulation driven by the a priori CO2 surface fluxes shows significant differences upwind of the Paris urban area, which suggests a large and uncertain contribution from distant sources and sinks to the CO2 concentration variability. This contribution advocates that the inversion should aim at minimising model-data misfits in upwind-downwind gradients rather than misfits in mole fractions at individual sites. Another conclusion of the direct model-measurement comparison is that the CO2 variability at the top of the Eiffel Tower is large and poorly represented by the model for most wind speeds and directions. The model's inability to reproduce the CO2 variability at the heart of the city makes such measurements ill-suited for the inversion. This and the need to constrain the budgets for the whole city suggests the assimilation of upwind-downwind mole fraction gradients between sites at the edge of the urban area only. The inversion significantly improves the agreement

  14. The CO2 inhibition of terrestrial isoprene emission significantly affects future ozone projections

    NASA Astrophysics Data System (ADS)

    Young, P. J.; Arneth, A.; Schurgers, G.; Zeng, G.; Pyle, J. A.

    2008-11-01

    Simulations of future tropospheric composition often include substantial increases in biogenic isoprene emissions arising from the Arrhenius-like leaf emission response and warmer surface temperatures, and from enhanced vegetation productivity in response to temperature and atmospheric CO2 concentration. However, a number of recent laboratory and field data have suggested a direct inhibition of leaf isoprene production by increasing atmospheric CO2 concentration, notwithstanding isoprene being produced from precursor molecules that include some of the primary products of carbon assimilation. The cellular mechanism that underlies the decoupling of leaf photosynthesis and isoprene production still awaits a full explanation but accounting for this observation in a dynamic vegetation model that contains a semi-mechanistic treatment of isoprene emissions has been shown to change future global isoprene emission estimates notably. Here we use these estimates in conjunction with a chemistry-climate model to compare the effects of isoprene simulations without and with a direct CO2-inhibition on late 21st century O3 and OH levels. The impact on surface O3 was significant. Including the CO2-inhibition of isoprene resulted in opposing responses in polluted (O3 decreases of up to 10 ppbv) vs. less polluted (O3 increases of up to 10 ppbv) source regions, due to isoprene nitrate and peroxy acetyl nitrate (PAN) chemistry. OH concentration increased with relatively lower future isoprene emissions, decreasing methane lifetime by ~7 months. Our simulations underline the large uncertainties in future chemistry and climate studies due to biogenic emission patterns and emphasize the problems of using globally averaged climate metrics to quantify the atmospheric impact of reactive, heterogeneously distributed substances.

  15. The CO2 inhibition of terrestrial isoprene emission significantly affects future ozone projections

    NASA Astrophysics Data System (ADS)

    Young, P. J.; Arneth, A.; Schurgers, G.; Zeng, G.; Pyle, J. A.

    2009-04-01

    Simulations of future tropospheric composition often include substantial increases in biogenic isoprene emissions arising from the Arrhenius-like leaf emission response and warmer surface temperatures, and from enhanced vegetation productivity in response to temperature and atmospheric CO2 concentration. However, a number of recent laboratory and field data have suggested a direct inhibition of leaf isoprene production by increasing atmospheric CO2 concentration, notwithstanding isoprene being produced from precursor molecules that include some of the primary products of carbon assimilation. The cellular mechanism that underlies the decoupling of leaf photosynthesis and isoprene production still awaits a full explanation but accounting for this observation in a dynamic vegetation model that contains a semi-mechanistic treatment of isoprene emissions has been shown to change future global isoprene emission estimates notably. Here we use these estimates in conjunction with a chemistry-climate model to compare the effects of isoprene simulations without and with a direct CO2-inhibition on late 21st century O3 and OH levels. The impact on surface O3 was significant. Including the CO2-inhibition of isoprene resulted in opposing responses in polluted (O3 decreases of up to 10 ppbv) vs. less polluted (O3 increases of up to 10 ppbv) source regions, due to isoprene nitrate and peroxy acetyl nitrate (PAN) chemistry. OH concentration increased with relatively lower future isoprene emissions, decreasing methane lifetime by ~7 months (6.6%). Our simulations underline the large uncertainties in future chemistry and climate studies due to biogenic emission patterns and emphasize the problems of using globally averaged climate metrics (such as global radiative forcing) to quantify the atmospheric impact of reactive, heterogeneously distributed substances.

  16. Effect of Alumina on the Gaseous Reduction of Magnetite in CO/CO2 Gas Mixtures

    NASA Astrophysics Data System (ADS)

    Kapelyushin, Yury; Xing, Xing; Zhang, Jianqiang; Jeong, Sunkwang; Sasaki, Yasushi; Ostrovski, Oleg

    2015-03-01

    Reduction of magnetite doped with alumina (3, 6 and 12 mass pct Al2O3) was studied using CO/CO2 gas mixture (80 vol pct CO) at 1023 K and 1123 K (750 °C and 850 °C). The reduction rate and degree of reduction were evaluated from the weight loss of a sample with time. The reduction behavior was analyzed using the results of XRD and SEM-EDS measurements and thermodynamic analysis. Effect of alumina on the magnetite reduction depended on the alumina content and temperature. Magnetite reduction at 1023 K (750 °C) was accelerated by the addition of 3 mass pct Al2O3, however, the rate of reduction significantly decreased with the further increase in the alumina content to 6 and 12 mass pct. Different effect of alumina was observed in reduction at 1123 K (850 °C); the rate of reduction of the Fe3O4-Al2O3 mixture with 6 mass pct Al2O3 was the fastest. Reduction of un-doped magnetite was developed topochemically with the formation of a dense iron shell. However, reduction of alumina-doped magnetite to wüstite started along certain lattice planes with the formation of network-like structure. In the course of reduction, Al3+ ions diffused from wüstite to the Fe3O4-FeAl2O4 solution enriching hercynite content in the solution at the reaction interface. Further reduction of alumina-rich Fe3O4-FeAl2O4 solution resulted in the formation of micro-cracks which enhanced the rate of the reduction process.

  17. Gas Hazard from Natural CO2 Emissions in Central and Southern Italy.

    NASA Astrophysics Data System (ADS)

    Cardellini, C.; Chiodini, G.; Costa, A.; Avino, R.; Baldini, A.; Caliro, S.; Frondini, F.; Granieri, D.; Minopoli, C.; Morgantini, N.

    2006-12-01

    Recent studies at regional scale showed that the central and southern Italy are affected by an active and intense process of CO2 Earth degassing. Considering the deeply derived carbon dissolved in the groundwater of large regional aquifers, Chiodini et al. (2004) elaborated a regional map of CO2 Earth degassing, pointing out the presence of two large CO2 degassing structures (62000 km2) a northern one, the tuscan roman degassing structure (TRDS) and a southern one, the campanian degassing structure (CDS). The deeply derived CO2 released by these two structures was estimated in ~ 9.2 Mt/y (Chiodini et al., 2004). This amount, which is globally relevant being ~ 10% of the present-day total CO2 discharge from subaerial volcanoes of the Earth, is of low magnitude with respect to the amount of CO2 that is estimated to be injected in the storage sites. TRDS and CDS are characterized by the presence of many vents of cold CO2 rich gases and areas of anomalous soil diffuse degassing of CO2. The gas manifestations are generally fed by buried carbonate reservoirs, covered by low permeability formations, where the gas produced at depth accumulates before the expulsion at the surface. More than 100 gas emissions are located in the Italian territory and represent a serious hazard for humans and animals. Gas flow rates are very high. For example, the biggest gas emissions daily release into atmosphere hundreds of tons of CO2, amounts similar to those released by diffuse degassing from active volcanoes (CO2 fluxes from 6 t/d to 2800 t/d, mean of 430 t/d, Morner and Etiope, 2002). Under stable atmospheric conditions and/or in presence of topographic depressions, CO2 air concentration can reach high values resulting in lethal effects to humans or animals. The last lethal accident occurred in 2003 in Tuscany, at Mt. Amiata. However, the most dangerous gas emission is Mefite d'Ansanto, located in the Southern Apennine, where three persons were killed during 1990's and historical

  18. No catalyst addition and highly efficient dissociation of H2O for the reduction of CO2 to formic acid with Mn.

    PubMed

    Lyu, Lingyun; Zeng, Xu; Yun, Jun; Wei, Feng; Jin, Fangming

    2014-05-20

    The "greenhouse effect" caused by the increasing atmospheric CO2 level is becoming extremely serious, and thus, the reduction of CO2 emissions has become an extensive, urgent, and long-term task. The dissociation of water for CO2 reduction with solar energy is regarded as one of the most promising methods for the sustainable development of the environment and energy. However, a high solar-to-fuel efficiency keeps a great challenge. In this work, the first observation of a highly effective, highly selective, and robust system of dissociating water for the reduction of carbon dioxide (CO2) into formic acid with metallic manganese (Mn) is reported. A considerably high formic acid yield of more than 75% on a carbon basis from NaHCO3 was achieved with 98% selectivity in the presence of simple commercially available Mn powder without the addition of any catalyst, and the proposed process is exothermic. Thus, this study may provide a promising method for the highly efficient dissociation of water for CO2 reduction by combining solar-driven thermochemistry with the reduction of MnO into Mn.

  19. No catalyst addition and highly efficient dissociation of H2O for the reduction of CO2 to formic acid with Mn.

    PubMed

    Lyu, Lingyun; Zeng, Xu; Yun, Jun; Wei, Feng; Jin, Fangming

    2014-05-20

    The "greenhouse effect" caused by the increasing atmospheric CO2 level is becoming extremely serious, and thus, the reduction of CO2 emissions has become an extensive, urgent, and long-term task. The dissociation of water for CO2 reduction with solar energy is regarded as one of the most promising methods for the sustainable development of the environment and energy. However, a high solar-to-fuel efficiency keeps a great challenge. In this work, the first observation of a highly effective, highly selective, and robust system of dissociating water for the reduction of carbon dioxide (CO2) into formic acid with metallic manganese (Mn) is reported. A considerably high formic acid yield of more than 75% on a carbon basis from NaHCO3 was achieved with 98% selectivity in the presence of simple commercially available Mn powder without the addition of any catalyst, and the proposed process is exothermic. Thus, this study may provide a promising method for the highly efficient dissociation of water for CO2 reduction by combining solar-driven thermochemistry with the reduction of MnO into Mn. PMID:24787746

  20. Impact of Heavy Duty Vehicle Emissions Reductions on Global Climate

    SciTech Connect

    Calvin, Katherine V.; Thomson, Allison M.

    2010-08-01

    The impact of a specified set of emissions reductions from heavy duty vehicles on climate change is calculated using the MAGICC 5.3 climate model. The integrated impact of the following emissions changes are considered: CO2, CH4, N2O, VOC, NOx, and SO2. This brief summarizes the assumptions and methods used for this calculation.

  1. Dual-phase spinel MnCo2O4 and spinel MnCo2O4/nanocarbon hybrids for electrocatalytic oxygen reduction and evolution.

    PubMed

    Ge, Xiaoming; Liu, Yayuan; Goh, F W Thomas; Hor, T S Andy; Zong, Yun; Xiao, Peng; Zhang, Zheng; Lim, Suo Hon; Li, Bing; Wang, Xin; Liu, Zhaolin

    2014-08-13

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential reactions for energy-storage and -conversion devices relying on oxygen electrochemistry. High-performance, nonprecious metal-based hybrid catalysts are developed from postsynthesis integration of dual-phase spinel MnCo2O4 (dp-MnCo2O4) nanocrystals with nanocarbon materials, e.g., carbon nanotube (CNT) and nitrogen-doped reduced graphene oxide (N-rGO). The synergic covalent coupling between dp-MnCo2O4 and nanocarbons effectively enhances both the bifunctional ORR and OER activities of the spinel/nanocarbon hybrid catalysts. The dp-MnCo2O4/N-rGO hybrid catalysts exhibited comparable ORR activity and superior OER activity compared to commercial 30 wt % platinum supported on carbon black (Pt/C). An electrically rechargeable zinc-air battery using dp-MnCo2O4/CNT hybrid catalysts on the cathode was successfully operated for 64 discharge-charge cycles (or 768 h equivalent), significantly outperforming the Pt/C counterpart, which could only survive up to 108 h under similar conditions. PMID:25058393

  2. Dual-phase spinel MnCo2O4 and spinel MnCo2O4/nanocarbon hybrids for electrocatalytic oxygen reduction and evolution.

    PubMed

    Ge, Xiaoming; Liu, Yayuan; Goh, F W Thomas; Hor, T S Andy; Zong, Yun; Xiao, Peng; Zhang, Zheng; Lim, Suo Hon; Li, Bing; Wang, Xin; Liu, Zhaolin

    2014-08-13

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential reactions for energy-storage and -conversion devices relying on oxygen electrochemistry. High-performance, nonprecious metal-based hybrid catalysts are developed from postsynthesis integration of dual-phase spinel MnCo2O4 (dp-MnCo2O4) nanocrystals with nanocarbon materials, e.g., carbon nanotube (CNT) and nitrogen-doped reduced graphene oxide (N-rGO). The synergic covalent coupling between dp-MnCo2O4 and nanocarbons effectively enhances both the bifunctional ORR and OER activities of the spinel/nanocarbon hybrid catalysts. The dp-MnCo2O4/N-rGO hybrid catalysts exhibited comparable ORR activity and superior OER activity compared to commercial 30 wt % platinum supported on carbon black (Pt/C). An electrically rechargeable zinc-air battery using dp-MnCo2O4/CNT hybrid catalysts on the cathode was successfully operated for 64 discharge-charge cycles (or 768 h equivalent), significantly outperforming the Pt/C counterpart, which could only survive up to 108 h under similar conditions.

  3. Examining ruthenium chromophores for the photochemical reduction of CO2 to methanol

    NASA Astrophysics Data System (ADS)

    Boston, David J.

    Our consumption of energy for transportation and electricity has been growing as quickly as our population. As this demand for energy increases we increase our production of carbon dioxide by the burning of fossil fuels to try and meet this increasing demand. A sustainable method to convert carbon dioxide (CO2) to a viable liquid fuel is one potential way in which both the increasing energy demand and increasing CO2 concentration issues can both be helped. Currently such methods being investigated include thermal, electrochemical, and photochemical processes. Because thermal conversion is not an ideal situation because of the requirement of strong reducing agents or extreme conditions such as steam reformation reactions, we need to find better alternatives such as electrochemical and photochemical methods. Both electrochemical and photochemical methods have the ability to be sustainable, however, the vast majority of these systems are limited to producing CO and/or formic acid, with only a few performing deeper reduction to products such formaldehyde, methanol and methane. All of the systems capable of reducing CO2 past two electrons involve either a heterogeneous catalyst (e.g. TiO2) or an electrode. In recent times Bocarsly and coworkers have shown that pyridine was capable of reducing CO2 to methanol through a sequential process of proton and electron transfers. This process seems to start with the formation of a CO2-pyridine adduct in solution that is reduced one more time to form formate/formic acid. The next reduction is a slow process and allows for a buildup of formate in solution leading to a higher formate concentration in solution. The subsequent reductions seem to occur very rapidly and form methanol at good efficiencies. Theoretical work done recently has argued for the necessity of the Pt, Pd, or GaP surface in the electrochemistry. Carter and coworkers have claimed that the surface of the electrode is a necessary part of the catalysis with the

  4. How could the family-scale photovoltaic module help the poor farmer out of poverty and reduce CO2 emission?

    NASA Astrophysics Data System (ADS)

    Qiu, Xu; Jin, Ran

    2016-04-01

    China, the world's most populous country, is facing great opportunities and challenges. On the one hand, China's increasing economy is raising hundreds of millions of people out of poverty. On the other hand, there are still 100 million of whose daily income is less than 1 US dollar. In addition, China is the world's largest solar panel producer and also the largest emitter of greenhouse gases. Could we find a feasible way to use solar panels to help the poor and meanwhile reduce CO2 emissions? To do this, we reviewed the literature and investigated the related field sites and institutions in China. Results show that the extension of family-scale photovoltaic modules to countryside could help. The 3 kW-module is recommended for widely distribution because its technology is mature and the cost is relatively low (3500 US dollars). Besides their own use to improve their living standard, farmers can sell the excess electricity to the grid at the price of 0.17 UD/kWh. The farmer's annual income could be increased by 460-615 US dollars by selling electricity, and this is equivalent to half of their annual income in many rural regions. The photovoltaic module can be used for 25 years and the payback period is 7 years. In addition to its economic benefit, the photovoltaic module can reduce CO2 emissions by 0.93 kg/kWh. This is equivalent to annual reduction of 3000-4000 kg CO2 per family. Therefore, it is concluded that the family-scale photovoltaic module not only can help the farmers out of poverty but also can reduce CO2 emissions significantly. To promote its sustainable development, it is worthwhile to further investigations its business models as well as the effects of long-term support policies under different social and nature conditions.

  5. Dissecting the steps of CO2 reduction: 1. The interaction of CO and CO2 with γ-Al2O3: an in situ FTIR study

    SciTech Connect

    Szanyi, Janos; Kwak, Ja Hun

    2014-08-07

    The adsorption of CO2 and CO was investigated on a pure γ-Al2O3 support material that has been used for the preparation of Pd and Ru catalysts for the catalytic reduction of CO2. The adsorption of CO2 resulted in the formation of carbonates, bicarbonates and linearly adsorbed CO2 species. The amount and the nature of the adsorbed species were dependent on the annealing temperature of the alumina support. On γ-Al2O3 annealed at 473 K mostly bicarbonates formed, while no adsorbed CO2 was seen on this highly hydroxylated surface. With increasing calcinations temperature, i.e., increasing extent of dehydroxylation, the amounts of both surface nitrates and linear adsorbed CO2 increased, but still the most abundant surface species were bicarbonates. Surface carbonates and adsorbed CO2 can readily be removed from the alumina surface, while bicarbonates are stable to elevated temperatures. The interaction of CO with γ-Al2O3 is much weaker than that of CO2. At room temperatures CO adsorbs only on Lewis acid sites, and can be readily removed by evacuation. At 100 K CO can probe different defect sites on the alumina surface (both Lewis acid sites and surface hydroxyls). Under no conditions we have observed the formation of any carbonates or bicarbonates upon the interaction of CO with the pure alumina support. In co-adsorption experiments CO competes for adsorption sites with the linearly adsorbed CO2 on the 773 K-annealed γ-Al2O3 surface; but it does not result in the desorption of CO2, rather in the increase of weakly-held carbonate production. After the removal of adsorbed CO, CO2 moves back to its original adsorption sites, i.e., Lewis acidic Al3+ centers. The exposure of a CO2-saturated γ-Al2O3 to H2O did not affect any of the adsorbed surface species. The findings of this study will be used to rationalize the results of our ongoing in situ and in operando studies on the reduction of CO2 on supported Pd and Ru catalysts. Acknowledgements: We gratefully acknowledge

  6. Reduction of CO2 to methanol catalyzed by a biomimetic organo-hydride produced from pyridine.

    PubMed

    Lim, Chern-Hooi; Holder, Aaron M; Hynes, James T; Musgrave, Charles B

    2014-11-12

    We use quantum chemical calculations to elucidate a viable mechanism for pyridine-catalyzed reduction of CO2 to methanol involving homogeneous catalytic steps. The first phase of the catalytic cycle involves generation of the key catalytic agent, 1,2-dihydropyridine (PyH2). First, pyridine (Py) undergoes a H(+) transfer (PT) to form pyridinium (PyH(+)), followed by an e(-) transfer (ET) to produce pyridinium radical (PyH(0)). Examples of systems to effect this ET to populate PyH(+)'s LUMO (E(0)(calc) ∼ -1.3 V vs SCE) to form the solution phase PyH(0) via highly reducing electrons include the photoelectrochemical p-GaP system (E(CBM) ∼ -1.5 V vs SCE at pH 5) and the photochemical [Ru(phen)3](2+)/ascorbate system. We predict that PyH(0) undergoes further PT-ET steps to form the key closed-shell, dearomatized (PyH2) species (with the PT capable of being assisted by a negatively biased cathode). Our proposed sequential PT-ET-PT-ET mechanism for transforming Py into PyH2 is analogous to that described in the formation of related dihydropyridines. Because it is driven by its proclivity to regain aromaticity, PyH2 is a potent recyclable organo-hydride donor that mimics important aspects of the role of NADPH in the formation of C-H bonds in the photosynthetic CO2 reduction process. In particular, in the second phase of the catalytic cycle, which involves three separate reduction steps, we predict that the PyH2/Py redox couple is kinetically and thermodynamically competent in catalytically effecting hydride and proton transfers (the latter often mediated by a proton relay chain) to CO2 and its two succeeding intermediates, namely, formic acid and formaldehyde, to ultimately form CH3OH. The hydride and proton transfers for the first of these reduction steps, the homogeneous reduction of CO2, are sequential in nature (in which the formate to formic acid protonation can be assisted by a negatively biased cathode). In contrast, these transfers are coupled in each of the two

  7. Toward Regional Fossil Fuel CO2 Emissions Verification Using WRF-CHEM

    NASA Astrophysics Data System (ADS)

    Delle Monache, L.; Kosoviæ, B.; Cameron-Smith, P.; Bergmann, D.; Grant, K.; Guilderson, T.

    2008-12-01

    As efforts to reduce emissions of green house gases take shape it is becoming obvious that an essential component of a viable solution will involve emission verification. While detailed inventories of green house gas sources will represent important component of the solution additional verification methodologies will be necessary to reduce uncertainties in emission estimates especially for distributed sources and CO2 offsets. We developed tools for solving inverse dispersion problem for distributed emissions of green house gases. For that purpose we combine probabilistic inverse methodology based on Bayesian inversion with stochastic sampling and weather forecasting and air quality model WRF-CHEM. We demonstrate estimation of CO2 emissions associated with fossil fuel burning in California over two one-week periods in 2006. We use WRF- CHEM in tracer simulation mode to solve forward dispersion problem for emissions over eleven air basins. We first use direct inversion approach to determine optimal location for a limited number of CO2 - C14 isotope sensors. We then use Bayesian inference with stochastic sampling to determine probability distributions for emissions from California air basins. Moreover, we vary the number of sensors and frequency of measurements to study their effect on the accuracy and uncertainty level of the emission estimation. Finally, to take into account uncertainties associated with forward modeling, we combine Bayesian inference and stochastic sampling with ensemble modeling. The ensemble is created by running WRF-CHEM with different initial and boundary conditions as well as different boundary layer and surface model options. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory (LLNL) under Contract DE-AC52-07NA27344 (LLNL-ABS-406901-DRAFT). The project 07-ERD- 064 was funded by the Laboratory Directed Research and Development Program at LLNL.

  8. Comparing two national datasets of CO2 Emissions for U.S. Powerplants

    NASA Astrophysics Data System (ADS)

    Huang, J.; Gurney, K. R.

    2011-12-01

    Fossil fuel CO2 emissions from powerplants account for about 40% of total U.S. fossil fuel CO2 emissions. The Energy Information Administration (EIA) Data and Clean Air Markets Data (CAMD) are two major primary power-plant CO2 emission datasets. EIA calculates CO2 emission by multiplying the heat input with CO2 emission factors. The CAMD dataset, by contrast, includes a mixture of measurement/calculation methods. The different measurement/calculation approaches in the two datasets generates differences at each emitting facility. The relative population difference over the last ten years between CAMD and EIA is 0.24% for all of the matched plants, 0.51% for NCHP (non-combined heat/power facilities), and -5.47% for CHP (combined heat/power facilities). Exploring the difference at the plant level (using 2007 as an example), we find that for both NCHP and CHP, the absolute emission differences are dominated by the very large powerplants. However, when these differences are represented as a percent of powerplant size, the small powerplants have proportionally larger biases (Fig 1). The hourly CAMD data and monthly EIA data also allows us to explore the elements that cause the emissions bias. From the CAMD data, we find that multiple measurement/calculation methods are employed during the year, which falls into six flagged categories. With about 1000 matched power plants between the two datasets, we can build a regression model to explore the relationships between the emissions differences and the measurement/calculation flag. Again taking 2007 as an example year, we find that if the CAMD data is "measured", it will be 0.6% lower than EIA data; if the CAMD data is "substituted", it will be 21.9% higher; if the data is "undetermined", it will be 2.5% higher. Because EIA provides the monthly heat input data by plant and fuel type, we can also build the regression model as a function of fuel type. We find that the burning of bituminous coal results in the CAMD data emitting

  9. Continuous measurements of CO2 emission from cultivated peat soil - effect of tillage intensity

    NASA Astrophysics Data System (ADS)

    Berglund, Örjan; Berglund, Kerstin

    2014-05-01

    Peatlands process and transfer significant quantities of greenhouse gases (GHG) such as CO2, CH4 and N2O. Most natural water-saturated peatlands sequester large amounts of CO2 from the atmosphere and emit CH4. Drainage and cultivation of peat soils increase soil aeration and reverse the carbon flux into net CO2 emissions, while CH4 emissions decrease and cultivated peat soils may even act as sinks for CH4. Fertile peat soils are potential sources of N2O when drained. In this investigation we used automatic dark chambers (ADC BioScientific Ltd) to measure CO2 emissions from plots with different soil tillage intensities. The field trial is located on the island Gotland east of the Swedish main land (57.584825N 18.47691E) and the soil is a peat soil with high pH (7.5) and organic content of 46.4 % (loss on ignition). The set-up was 4 treatments repeated in 4 blocks. Each plot was 18 by 25 meters and the following treatments were tested: A. Ploughing every year B. Ploughing 1 out of 4 years C. Only stubble cultivation D. Permanent ley One chamber was put in each plot and connected to a master control unit to create a network with 16 chambers. Measurements were made every hour during most of 2012 (17/4- 6/11 with some gaps) and every second hour during 2013 (22/4-27/6). Higher emissions could be observed just after cultivation and that effect lasted for about one day. The average emission was highest from treatment D during 2012 (4.53 μmol m-2 s-1) and treatment C and D during 2013 (3.85 μmol m-2 s-1).

  10. Detecting Long-term Changes in Point Source Fossil CO2 Emissions with Tree Ring Archives

    NASA Astrophysics Data System (ADS)

    Keller, E. D.; Turnbull, J. C.; Norris, M. W.

    2015-12-01

    We examine the utility of tree ring 14C archives for detecting long term changes in fossil CO2 emissions from a point source. Trees assimilate carbon from the atmosphere during photosynthesis, in the process faithfully recording the average atmospheric 14C content over the growing season in each annual tree ring. Using 14C as a proxy for fossil CO2, we examine interannual variability over six years of fossil CO2 observations between 2004 and 2012 from two trees growing near the Kapuni Natural Gas Plant in rural Taranaki, New Zealand. We quantify the amount of variability that can be attributed to transport and meteorology by simulating constant point source fossil CO2 emissions over the observation period with the atmospheric transport model WindTrax. We then calculate the amount of change in emissions that we can detect with new observations over annual or multi-year time periods given both measurement uncertainty of 1ppm and the modelled variation in transport. In particular, we ask, what is the minimum amount of change in emissions that we can detect using this method, given a reference period of six years? We find that changes of 42% or more could be detected in a new sample from one year at the pine tree, or 22% in the case of four years of new samples. This threshold lowers and the method becomes more practical with a larger signal; for point sources 10 times the magnitude of the Kapuni plant (a typical size for large electricity generation point sources worldwide), it would be possible to detect sustained emissions changes on the order of 10% given suitable meteorology and observations.

  11. Aircraft mass budgeting to measure CO2 emissions of Rome, Italy.

    PubMed

    Gioli, Beniamino; Carfora, Maria F; Magliulo, Vincenzo; Metallo, Maria C; Poli, Attilio A; Toscano, Piero; Miglietta, Franco

    2014-04-01

    Aircraft measurements were used to estimate the CO2 emission rates of the city of Rome, assessed against high-resolution inventorial data. Three experimental flights were made, composed of vertical soundings to measure Planetary Boundary Layer (PBL) properties, and circular horizontal transects at various altitudes around the city area. City level emissions and associated uncertainties were computed by means of mass budgeting techniques, obtaining a positive net CO2 flux of 14.7 ± 4.5, 2.5 ± 1.2, and 10.3 ± 1.2 μmol m(-2) s(-1) for the three flights. Inventorial CO2 fluxes at the time of flights were computed by means of spatial and temporal disaggregation of the gross emission inventory, at 10.9 ± 2.5, 9.6 ± 1.3, and 17.4 ± 9.6 μmol m(-2) s(-1). The largest differences between the two dataset are associated with a greater variability of wind speed and direction in the boundary layer during measurements. Uncertainty partitioned into components related to horizontal boundary flows and top surface flow, revealed that the latter dominates total uncertainty in the presence of a wide variability of CO2 concentration in the free troposphere (up to 7 ppm), while it is a minor term with uniform tropospheric concentrations in the study area (within 2 ppm). Overall, we demonstrate how small aircraft may provide city level emission measurements that may integrate and validate emission inventories. Optimal atmospheric conditions and measurement strategies for the deployment of aircraft experimental flights are finally discussed.

  12. Predicting CO2 and SO2 emissions in the Baltic States through reorganization of energy infrastructure.

    PubMed

    Denafas, Gintaras; Sitnikovas, Denisas; Galinis, Arvydas; Kudrenickis, Ivars; Klavs, Gaidis; Kuusik, Rein

    2004-10-01

    The paper deals with predicting carbon dioxide and sulphur dioxide emissions generated by power production sector in the Baltic States in period up to year 2020. The economies of Lithuania, Latvia and Estonia are rapidly growing therefore forecast of emissions related with this occurrence becomes very important. The Ignalina Nuclear Power Plant (INPP), one of the largest in the world, is situated in the region. Two power production scenarios are modelled to investigate changes in power sector's emissions expected as the consequences of the coming closure of Ignalina NPP. Power market was assumed to be common for all three Baltic countries and was modelled by applying the Balmorel model. The planned closure of Ignalina NPP will bring restructuring of Lithuania power production sector and will change also power transmission between countries. Predictive identified the potential of investments for new modern power generation technologies. At the same time, modelling results show in both scenarios that CO(2) and SO(2) emissions from power production in the Baltic region will increase. The increment of emissions is discussed in the context of meeting requirements of UNFCCC Kyoto protocol and EC Directives. Despite of CO(2) emissions increase the Kyoto protocol's requirements may be expected. At the same time, SO(2) formation in Lithuania power sector may exceed the limits of the EU Council Directive 2001/80/EB therefore the additional measures to control SO(2) emissions have to be investigated.

  13. Predicting CO2 and SO2 emissions in the Baltic States through reorganization of energy infrastructure.

    PubMed

    Denafas, Gintaras; Sitnikovas, Denisas; Galinis, Arvydas; Kudrenickis, Ivars; Klavs, Gaidis; Kuusik, Rein

    2004-10-01

    The paper deals with predicting carbon dioxide and sulphur dioxide emissions generated by power production sector in the Baltic States in period up to year 2020. The economies of Lithuania, Latvia and Estonia are rapidly growing therefore forecast of emissions related with this occurrence becomes very important. The Ignalina Nuclear Power Plant (INPP), one of the largest in the world, is situated in the region. Two power production scenarios are modelled to investigate changes in power sector's emissions expected as the consequences of the coming closure of Ignalina NPP. Power market was assumed to be common for all three Baltic countries and was modelled by applying the Balmorel model. The planned closure of Ignalina NPP will bring restructuring of Lithuania power production sector and will change also power transmission between countries. Predictive identified the potential of investments for new modern power generation technologies. At the same time, modelling results show in both scenarios that CO(2) and SO(2) emissions from power production in the Baltic region will increase. The increment of emissions is discussed in the context of meeting requirements of UNFCCC Kyoto protocol and EC Directives. Despite of CO(2) emissions increase the Kyoto protocol's requirements may be expected. At the same time, SO(2) formation in Lithuania power sector may exceed the limits of the EU Council Directive 2001/80/EB therefore the additional measures to control SO(2) emissions have to be investigated. PMID:15337350

  14. Emissions of N2O, CH4 and CO2 from tropical forest soils

    NASA Technical Reports Server (NTRS)

    Keller, Michael; Kaplan, Warren A.; Wofsy, Steven C.

    1986-01-01

    Emissions of nitrous oxide, methane, and carbon dioxide were measured at diverse locations in tropical forests of Brazil, Ecuador, and Puerto Rico using a static open chamber technique. Mean fluxes to the atmosphere were 1.7 x 10 to the 10th, -0.7 x 10 to the 10th, and 1.5 x 10 to the 14th molecules/sq cm per s for N2O, CH4, and CO2, respectively. The data indicate that tropical forests contribute a significant fraction of the global source for atmospheric N2O, about 40 percent of the current source, and possibly 75 percent of the preindustrial source. Methane is consumed by soils on average, but the sink is an insignificant part (less than 5 percent) of the atmospheric cycle for the gas. Emissions of CO2 from forest soils are higher at equatorial sites than at middle or high latitudes, as expected from ecological considerations. Soils emit CO2 at rates more than twice as large as the rate of carbon infall in litter; hence much of the emitted CO2 must arise from root metabolism.

  15. Biomass Consumption, CO2, CO and Main Hydrocarbon Gas Emissions in an Amazonian Forest Clearing Fire

    NASA Astrophysics Data System (ADS)

    Alvarado, E.; Soares Neto, T. G.; de Carvalho, J. A.; Gurgel Veras, C. A.; Lincoln, E. N.; Yokelson, R.; Hao, W. M.; Dos Santos, J. C.

    2006-12-01

    Biomass consumption, CO2, CO and main hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, in the state of Mato Grosso, Brazil. The average carbon content of dry biomass used was 48% and the estimated average moisture content of fresh biomass was 42% on wet weight basis. The fresh biomass in the field test was estimated as 528 t.ha-1 and the amount of carbon on the ground before burning was 147 t.ha-1. The overall combustion efficiency for the experiment was 23.9%. The gases measured were: CO2, CO, CH4, C2-C3 hydrocarbons, and particulates. Concentrations of emitted CH4 and C2-C3 hydrocarbons were linearly correlated with those of CO. The combustion efficiencies for flaming, transitional, and smoldering phases were 0.949, 0.889 and 0.844, respectively. The average emission factors of CO2, CO, CH4, NMHC and PM2.5 were respectively 1,599, 111.3, 9.2, 5.57 and 4.84 grams per kg of burned dry biomass. One hectare of burnt forest released about 117,000 Kg of CO2, 8,100 Kg of CO, 675 Kg of CH4, 407 Kg of NMHC and 354 Kg of particulates.

  16. Changing Land Use to Offset CO2 Emissions: Limited Potential for the Upper Midwest of the U.S.

    NASA Astrophysics Data System (ADS)

    Fissore, C.; Espelata, J. F.; Nater, E. A.; Hobbie, S. E.; Reich, P. B.

    2008-12-01

    Efforts to mitigate increasing carbon (C) emissions are needed, and increasingly more policies point at terrestrial ecosystems as places to sequester atmospheric CO2. Whether terrestrial C sequestration can offset significant CO2 emissions is questionable, particularly in light of (1) increasing pressures on land use from an array of competing sectors including food and biofuel production and urbanization, and (2) a growing concern among scientists that previously published rates of C sequestration attributed to the conversion from conventional tillage to no-till or conservation tillage were overly optimistic. We analyzed the potential to promote terrestrial C sequestration through changes in land use and land cover in the Upper Midwest of the U.S. over a 50-year timeframe based on available data. Although some land use and cover changes, such as restoring forests, grasslands and wetlands, cause substantial carbon storage for a given area of land, conversion of even 10% of the regions agricultural land would offset only a few percent of its carbon emissions. Conversion to no-till agricultural, although popular among policymakers, results in variable and, on average, negligible C sequestration (sequestration rates range from -0.2 to 0.8 Mg C ha-1 y-1). Despite the unquestionable ecological benefits of some of the proposed land use changes, land use change realistically can be only a modest part of a more comprehensive strategy to achieve significant emissions reductions.

  17. Tracing CO2 fluxes and plant volatile organic compound emissions by stable isotopes

    NASA Astrophysics Data System (ADS)

    Werner, Christiane; Wegener, Frederik; Jardine, Kolby

    2014-05-01

    Plant metabolic processes exert a large influence on global climate and air quality through the emission of the greenhouse gas CO2 and volatile organic compounds (VOCs). Despite the enormous importance, processes controlling plant carbon allocation into primary and secondary metabolism, such as respiratory CO2 emission and VOC synthesis, remains unclear. The vegetation exerts a large isotopic imprint on the atmosphere through both, photosynthetic carbon isotope discrimination and fractionation during respiratory CO2 release (δ13Cres). While the former is well understood, many processes driving carbon isotope fractionation during respiration are unknown1. There are striking differences in variations of δ13Cres between plant functional groups, which have been proposed to be related to carbon partitioning in the metabolic branching points of the respiratory pathways and secondary metabolism, which are linked via a number of interfaces including the central metabolite pyruvate2. Notably, it is a known substrate in a large array of secondary pathways leading to the biosynthesis of many volatile organic compounds (VOCs), such as volatile isoprenoids, oxygenated VOCs, aromatics, fatty acid oxidation products, which can be emitted by plants. Here we investigate if carbon isotope fractionation in light and dark respired CO2 is associated with VOC emissions in the atmosphere. Specifically, we hypothesize that a high carbon flux through the pyruvate into various VOC synthesis pathways is associated with a pronounced 13C-enrichment of respired CO2 above the putative substrate, as it involves the decarboxylation of the 13C-enriched C-1 from pyruvate. Based on simultaneous real-time measurements of stable carbon isotope composition of branch respired CO2 (CRDS) and VOC fluxes (PTR-MS) we traced carbon flow into these pathways by pyruvate positional labeling. We demonstrated that in a Mediterranean shrub the 13C-enriched C-1 from pyruvate is released in substantial amounts as

  18. Highly Efficient and Selective Photocatalytic CO2 Reduction by Iron and Cobalt Quaterpyridine Complexes.

    PubMed

    Guo, Zhenguo; Cheng, Siwei; Cometto, Claudio; Anxolabéhère-Mallart, Elodie; Ng, Siu-Mui; Ko, Chi-Chiu; Liu, Guijian; Chen, Lingjing; Robert, Marc; Lau, Tai-Chu

    2016-08-01

    The design of highly efficient and selective photocatalytic systems for CO2 reduction that are based on nonexpensive materials is a great challenge for chemists. The photocatalytic reduction of CO2 by [Co(qpy)(OH2)2](2+) (1) (qpy = 2,2':6',2″:6″,2‴-quaterpyridine) and [Fe(qpy)(OH2)2](2+) (2) have been investigated. With Ru(bpy)3(2+) as the photosensitizer and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole as the sacrificial reductant in CH3CN/triethanolamine solution under visible-light excitation (blue light-emitting diode), a turnover number (TON) for CO as high as 2660 with 98% selectivity can be achieved for the cobalt catalyst. In the case of the iron catalyst, the TON was >3000 with up to 95% selectivity. More significantly, when Ru(bpy)3(2+) was replaced by the organic dye sensitizer purpurin, TONs of 790 and 1365 were achieved in N,N-dimethylformamide for the cobalt and iron catalysts, respectively. PMID:27443679

  19. Single Unit Cell Bismuth Tungstate Layers Realizing Robust Solar CO2 Reduction to Methanol.

    PubMed

    Liang, Liang; Lei, Fengcai; Gao, Shan; Sun, Yongfu; Jiao, Xingchen; Wu, Ju; Qamar, Shaista; Xie, Yi

    2015-11-16

    Solar CO2 reduction into hydrocarbons helps to solve the global warming and energy crisis. However, conventional semiconductors usually suffer from low photoactivity and poor photostability. Here, atomically-thin oxide-based semiconductors are proposed as excellent platforms to overcome this drawback. As a prototype, single-unit-cell Bi2WO6 layers are first synthesized by virtue of a lamellar Bi-oleate intermediate. The single-unit-cell thickness allows 3-times larger CO2 adsorption capacity and higher photoabsorption than bulk Bi2WO6. Also, the increased conductivity, verified by density functional theory calculations and temperature-dependent resistivities, favors fast carrier transport. The carrier lifetime increased from 14.7 to 83.2 ns, revealed by time-resolved fluorescence spectroscopy, which accounts for the improved electron-hole separation efficacy. As a result, the single-unit-cell Bi2WO6 layers achieve a methanol formation rate of 75 μmol g(-1) h(-1), 125-times higher than that of bulk Bi2WO6. The catalytic activity of the single-unit-cell layers proceeds without deactivation even after 2 days. This work will shed light on designing efficient and robust photoreduction CO2 catalysts.

  20. Spinel ZnCo2O4/N-doped carbon nanotube composite: A high active oxygen reduction reaction electrocatalyst

    NASA Astrophysics Data System (ADS)

    Pu, Zonghua; Liu, Qian; Tang, Chun; Asiri, Abdullah M.; Qusti, Abdullah H.; Al-Youbi, Abdulrahman O.; Sun, Xuping

    2014-07-01

    In this communication, we report on the solvothermal preparation of spinel ZnCo2O4/N-doped carbon nanotube (ZnCo2O4/NCNT) composite. As a novel oxygen reduction reaction (ORR) electrocatalyst, the ZnCo2O4/NCNT composite shows high activity via a four-electron pathway in alkaline solution. Such catalyst also exhibits superior methanol tolerance ability and durability over commercial Pt/C catalyst.

  1. Co3 O4 Hexagonal Platelets with Controllable Facets Enabling Highly Efficient Visible-Light Photocatalytic Reduction of CO2.

    PubMed

    Gao, Chao; Meng, Qiangqiang; Zhao, Kun; Yin, Huajie; Wang, Dawei; Guo, Jun; Zhao, Shenlong; Chang, Lin; He, Meng; Li, Qunxiang; Zhao, Huijun; Huang, Xingjiu; Gao, Yan; Tang, Zhiyong

    2016-08-01

    A heterogeneous catalyst made of well-defined Co3 O4 hexagonal platelets with varied exposed facets is coupled with [Ru(bpy)3 ]Cl2 photosensitizers to effectively and efficiently reduce CO2 under visible-light irradiation. Systematic investigation based on both experiment and theory discloses that the exposed {112} facets are crucial for activating CO2 molecules, giving rise to significant enhancement of photocatalytic CO2 reduction efficiency. PMID:27171564

  2. Contribution of Soil Carbonates to CO2 Emissions Following Land Use Change

    NASA Astrophysics Data System (ADS)

    Grand, S.; Rothstein, D.

    2014-12-01

    Land disturbance is known to contribute to carbon dioxide emission through accelerated decomposition of soil organic matter. Many soils also contain large stocks of potentially reactive inorganic C (Ci) in the form of carbonate minerals. Under strong acidification conditions, as can be generated by nitrification and other biogeochemical reactions, carbonate weathering has the potential to generate CO2 emissions on a short time scale; yet little is known about the contribution of this process to disturbance-related C emissions. Information is particularly scarce for high-latitude alkaline soils. The objective of this study is to determine the contribution of Ci to total greenhouse gas emissions from soil following a land disturbance event. The perturbation consisted of the conversion of long-idled agricultural land to a woody bioenergy plantation. We hypothesized that this land use change would intensify acidification processes and increase the release of Ci. We tested this hypothesis by monitoring greenhouse gas emissions during the establishment of a poplar plantation on soils developed from limestone-derived glacial drift in northern Michigan, USA. We used 13C natural abundance to estimate the contribution of Ci to soil C emissions. We found that carbonates were abundant in the soil profile despite the leaching associated with the humid climate. Carbonate-C concentration averaged 2 g/kg in the topsoil and 15 to 25 g/kg in the deep subsoil. The persistence of measurable carbonate concentrations above the expected weathering front was likely due to biological translocation processes. Using a Bayesian isotopic mixing model accounting for endmember uncertainties, we detected a significant contribution of Ci to total soil CO2 emissions at the plot scale. There was a significant interaction between disturbance and season. In the spring, Ci emissions were three times higher in newly established poplar plots than in control plots. In the summer, Ci emissions in control

  3. Open framework metal chalcogenides as efficient photocatalysts for reduction of CO2 into renewable hydrocarbon fuel.

    PubMed

    Sasan, Koroush; Lin, Qipu; Mao, Chengyu; Feng, Pingyun

    2016-06-01

    Open framework metal chalcogenides are a family of porous semiconducting materials with diverse chemical compositions. Here we show that these materials containing covalent three-dimensional superlattices of nanosized supertetrahedral clusters can function as efficient photocatalysts for the reduction of CO2 to CH4. Unlike dense semiconductors, metal cations are successfully incorporated into the channels of the porous semiconducting materials to further tune the physical properties of the materials such as electrical conductivity and band gaps. In terms of the photocatalytic properties, the metal-incorporated porous chalcogenides demonstrated enhanced solar energy absorption and higher electrical conductivity and improved photocatalytic activity. PMID:27186825

  4. Long-term changes in CO2 emissions in Austria and Czechoslovakia—Identifying the drivers of environmental pressures

    PubMed Central

    Gingrich, Simone; Kušková, Petra; Steinberger, Julia K.

    2011-01-01

    This study presents fossil-fuel related CO2 emissions in Austria and Czechoslovakia (current Czech Republic and Slovakia) for 1830–2000. The drivers of CO2 emissions are discussed by investigating the variables of the standard Kaya identity for 1920–2000 and conducting a comparative Index Decomposition Analysis. Proxy data on industrial production and household consumption are analysed to understand the role of the economic structure. CO2 emissions increased in both countries in the long run. Czechoslovakia was a stronger emitter of CO2 throughout the time period, but per-capita emissions significantly differed only after World War I, when Czechoslovakia and Austria became independent. The difference in CO2 emissions increased until the mid-1980s (the period of communism in Czechoslovakia), explained by the energy intensity and the composition effects, and higher industrial production in Czechoslovakia. Counterbalancing factors were the income effect and household consumption. After the Velvet revolution in 1990, Czechoslovak CO2 emissions decreased, and the energy composition effect (and industrial production) lost importance. Despite their different political and economic development, Austria and Czechoslovakia reached similar levels of per-capita CO2 emissions in the late 20th century. Neither Austrian “eco-efficiency” nor Czechoslovak restructuring have been effective in reducing CO2 emissions to a sustainable level. PMID:21461052

  5. Long-term changes in CO(2) emissions in Austria and Czechoslovakia-Identifying the drivers of environmental pressures.

    PubMed

    Gingrich, Simone; Kušková, Petra; Steinberger, Julia K

    2011-02-01

    This study presents fossil-fuel related CO(2) emissions in Austria and Czechoslovakia (current Czech Republic and Slovakia) for 1830-2000. The drivers of CO(2) emissions are discussed by investigating the variables of the standard Kaya identity for 1920-2000 and conducting a comparative Index Decomposition Analysis. Proxy data on industrial production and household consumption are analysed to understand the role of the economic structure. CO(2) emissions increased in both countries in the long run. Czechoslovakia was a stronger emitter of CO(2) throughout the time period, but per-capita emissions significantly differed only after World War I, when Czechoslovakia and Austria became independent. The difference in CO(2) emissions increased until the mid-1980s (the period of communism in Czechoslovakia), explained by the energy intensity and the composition effects, and higher industrial production in Czechoslovakia. Counterbalancing factors were the income effect and household consumption. After the Velvet revolution in 1990, Czechoslovak CO(2) emissions decreased, and the energy composition effect (and industrial production) lost importance. Despite their different political and economic development, Austria and Czechoslovakia reached similar levels of per-capita CO(2) emissions in the late 20th century. Neither Austrian "eco-efficiency" nor Czechoslovak restructuring have been effective in reducing CO(2) emissions to a sustainable level.

  6. Reducing CO2 emissions from domestic travel: exploring the social and health impacts.

    PubMed

    Greenaway, Sarah; McCreanor, Tim; Witten, Karen

    2008-12-01

    The importance and meaning of social and recreational travel for a diverse group of Auckland residents is explored in this article. Study participants identified a range of social and health benefits, including maintaining social connections with family and friends, opportunities to participate in physical activity, and reducing stress. However, many of these trips are by car. New Zealand has one of the highest rates of private car ownership internationally, low-density urban development, and a poor public transport infrastructure. Social and recreational trips make up a sizeable proportion of domestic travel and are contributing to New Zealand's increasing rate of CO2 emissions. There is an obvious need to address the negative ecological impacts of human activity. Our findings suggest that alongside strategies to reduce CO2 emissions, it also is important to introduce measures to maintain the benefits from social and recreational travel. Suggestions are made for further areas of research.

  7. Emission Spectrochemical Analysis of Food Material Using TEA CO2 Laser-Induced Shock Wave Plasma

    NASA Astrophysics Data System (ADS)

    Kagawa, Kiichiro; Deguchi, Yoji; Ogata, Akira; Kurniawan, Hendrick; Ikeda, Noriko; Takagi, Yasuhiro

    1991-11-01

    A new method for spectrochemical analysis of food materials is presented using a Transverse Excited Atmospheric (TEA) CO2 laser. Milk powders containing different amounts of Ca are mixed with KBr powder, and compressed to make pellets. The pellets are bombarded by the TEA CO2 laser (300 mJ, 100 ns) under the surrounding gas of 300 Pa. The shape of the luminous plasma is hemispherical. This plasma is excited by the shock wave induced by the laser bombardment. It is proved that the relative intensity of the Ca 422.6-nm emission line to that of the K 404.4-nm emission line is proportional to the Ca content. This method has a bright prospect as a direct analytical method of food materials.

  8. Students' Understanding of the Greenhouse Effect, the Societal Consequences of Reducing CO2 Emissions and the Problem of Ozone Layer Depletion.

    ERIC Educational Resources Information Center

    Andersson, Bjorn; Wallin, Anita

    2000-01-01

    Contributes to the growing body of knowledge about students' conceptions and views of environmental and natural resource issues. Questions 9th and 12th grade Swedish students' understandings of the greenhouse effect, reduction of CO2 emissions, and the depletion of the ozone layer. Observes five models of the greenhouse effect that appear among…

  9. Point-source CO2 emission estimation from airborne sampled CO2 mass density: a case study for an industrial plant in Biganos, Southern France.

    NASA Astrophysics Data System (ADS)

    Carotenuto, Federico; Gioli, Beniamino; Toscano, Piero; Zaldei, Alessandro; Miglietta, Franco

    2013-04-01

    One interesting aspect in the airborne sampling of ground emissions of all types (from CO2 to particulate matter) is the ability to understand the source from which these emissions originated and, therefore, obtain an estimation of that ground source's strength. Recently an aerial campaign has been conducted in order to sample emissions coming from a paper production plant in Biganos (France). The campaign made use of a Sky Arrow ERA (Environmental Research Aircraft) equipped with a mobile flux platform system. This latter system couples (among the various instrumentation) a turbulence probe (BAT) and a LICOR 7500 open-path infra-red gas analyzer that also enables the estimation of high-resolution fluxes of different scalars via the spatial-integrated eddy-covariance technique. Aircraft data showed a marked increase in CO2 mass density downwind the industrial area, while vertical profiles samplings showed that concentrations were changing with altitude. The estimation of the CO2 source was obtained using a simple mass balance approach, that is, by integrating the product of CO2 concentration and the mass flow rate through a cross-sectional area downwind of the point source. The results were compared with those obtained by means of a "forward-mode" Lagrangian dispersion model operated iteratively. CO2 source strength were varied at each iteration to obtain an optimal convergence between the modeled atmospheric concentrations and the concentration data observed by the aircraft. The procedure makes use of wind speed and atmospheric turbulence data which are directly measured by the BAT probe at different altitudes. The two methods provided comparable estimates of the CO2 source thus providing a substantial validation of the model-based iterative dispersion procedure. We consider that this data-model integration approach involving aircraft surveys and models may substantially enhance the estimation of point and area sources of any scalar, even in more complex

  10. Toward observationally constrained high space and time resolution CO2 urban emission inventories

    NASA Astrophysics Data System (ADS)

    Maness, H.; Teige, V. E.; Wooldridge, P. J.; Weichsel, K.; Holstius, D.; Hooker, A.; Fung, I. Y.; Cohen, R. C.

    2013-12-01

    The spatial patterns of greenhouse gas (GHG) emission and sequestration are currently studied primarily by sensor networks and modeling tools that were designed for global and continental scale investigations of sources and sinks. In urban contexts, by design, there has been very limited investment in observing infrastructure, making it difficult to demonstrate that we have an accurate understanding of the mechanism of emissions or the ability to track processes causing changes in those emissions. Over the last few years, our team has built a new high-resolution observing instrument to address urban CO2 emissions, the BErkeley Atmospheric CO2 Observing Network (BEACON). The 20-node network is constructed on a roughly 2 km grid, permitting direct characterization of the internal structure of emissions within the San Francisco East Bay. Here we present a first assessment of BEACON's promise for evaluating the effectiveness of current and upcoming local emissions policy. Within the next several years, a variety of locally important changes are anticipated--including widespread electrification of the motor vehicle fleet and implementation of a new power standard for ships at the port of Oakland. We describe BEACON's expected performance for detecting these changes, based on results from regional forward modeling driven by a suite of projected inventories. We will further describe the network's current change detection capabilities by focusing on known high temporal frequency changes that have already occurred; examples include a week of significant freeway traffic congestion following the temporary shutdown of the local commuter rail (the Bay Area Rapid Transit system).

  11. An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements

    NASA Astrophysics Data System (ADS)

    Bréon, F. M.; Broquet, G.; Puygrenier, V.; Chevallier, F.; Xueref-Rémy, I.; Ramonet, M.; Dieudonné, E.; Lopez, M.; Schmidt, M.; Perrussel, O.; Ciais, P.

    2014-04-01

    Atmospheric concentration measurements are used to adjust the daily to monthly budget of CO2 emissions from the AirParif inventory of the Paris agglomeration. We use 5 atmospheric monitoring sites including one at the top of the Eiffel tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model. The inversion tool adjusts the CO2 fluxes (anthropogenic and biogenic) with a temporal resolution of 6 h, assuming temporal correlation of emissions uncertainties within the daily cycle and from day to day, while keeping the a priori spatial distribution from the emission inventory. The inversion significantly improves the agreement between measured and modelled concentrations. However, the amplitude of the atmospheric transport errors is often large compared to the CO2 gradients between the sites that are used to estimate the fluxes, in particular for the Eiffel tower station. In addition, we sometime observe large model-measurement differences upwind from the Paris agglomeration, which confirms the large and poorly constrained contribution from distant sources and sinks included in the prescribed CO2 boundary conditions These results suggest that (i) the Eiffel measurements at 300 m above ground cannot be used with the current system and (ii) the inversion shall rely on the measured upwind-downwind gradients rather than the raw mole fraction measurements. With such setup, realistic emissions are retrieved for two 30 day periods. Similar inversions over longer periods are necessary for a proper evaluation of the results.

  12. CO2-MEGAPARIS: Quantification of CO2 emissions from Paris megacity and their spread out to the neightbouring Centre region. (Invited)

    NASA Astrophysics Data System (ADS)

    Xueref-Remy, I.

    2010-12-01

    Atmospheric CO2 concentration has been increasing of more than 30% since the pre-industrial era due to human activities, and is very likely involved in the recent global temperature increase [IPCC, 2007]. Although we have good estimates of the CO2 fluxes on a global basis, and have a relatively well-established system to detect the large-scale trends, regional information (10-500km) is needed if society is ever to manage or verify carbon emissions. We must improve our understanding of regional variations in the sources and sinks of CO2 because they help identify possible sequestration or emission management options. New programs are needed to improve our understanding of meso-scale carbon fluxes, and to discriminate between the anthropogenic and biospheric sources which are very strongly overlapped in European countries. In this context we need to monitor the emissions originating from the megalopolis such as Paris and its agglomeration, and the way they are spreading in the background atmosphere. Nowadays, inventories (CITEPA, AIRPARIF) based on statistical information provide CO2 emissions from Ile de France and all others regions of France, but no independent verification based on CO2 measurements has been done yet. Atmospheric measurements coupled to a meso-scale model can be used to provide such verification, especially to detect the interannual and decadal trends which could result from regional management strategy. The CO2-MEGAPARIS project (2009-2012) objective is to develop four independent methods to verify the emission inventories, and to monitor the daily to monthly CO2 emissions from Ile de France as well as their spreading to neighbouring regions with a scale up to 2x2 km2. The first method consists in developing a synergy between a mesoscale model (CHIMERE/MM5), inventories and observations using a top-down approach based on an inversion technique to retrieve surface fluxes (3 new observing stations are developed among which the top of the Eiffel

  13. The growth response of Alternanthera philoxeroides in a simulated post-combustion emission with ultrahigh [CO2] and acidic pollutants.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L; Blazier, John C; Craig, Elizabeth C; Gilbert, Dominique S; Sritrairat, Sanpisa; Anderson, O Roger; Castaldi, Marco J; Beaumont, Larry

    2009-07-01

    Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO2 that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO2] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 micromol mol(-1) [CO2] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 micromol mol(-1) [CO2], but declined when [CO2] rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO2 and NO2) significantly offset the CO2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO2 from the power plant emissions to optimize growth in commercial green house could be viable.

  14. Summit CO2 emission rates by the CO2/SO2 ratio method at Kīlauea Volcano, Hawaiʻi, during a period of sustained inflation

    USGS Publications Warehouse

    Hager, S.A.; Gerlach, T.M.; Wallace, P.J.

    2008-01-01

    The emission rate of carbon dioxide escaping from the summit of Kīlauea Volcano, Hawaiʻi, proved highly variable, averaging 4900 ± 2000 metric tons per day (t/d) in June–July 2003 during a period of summit inflation. These results were obtained by combining over 90 measurements of COSPEC-derived SO2emission rates with synchronous CO2/SO2 ratios of the volcanic gas plume along the summit COSPEC traverse. The results are lower than the CO2 emission rate of 8500 ± 300 t/d measured by the same method in 1995–1999 during a period of long-term summit deflation [Gerlach, T.M., McGee, K.A., Elias, T., Sutton, A.J. and Doukas, M.P., 2002. Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir. Journal of Geophysical Research-Solid Earth, 107(B9): art. no.-2189.]. Analysis of the data indicates that the emission rates of the present study likely reflect changes in the magma supply rate and residence time in the summit reservoir. It is also likely that emission rates during the inflation period were heavily influenced by SO2 pulses emitted adjacent to the COSPEC traverse, which biased CO2/SO2 ratios towards low values that may be unrepresentative of the global summit gas plume. We conclude that the SO2 pulses are consequences of summit re-inflation under way since 2003 and that CO2 emission rates remain comparable to, but more variable than, those measured prior to re-inflation.

  15. Summit CO 2 emission rates by the CO 2/SO 2 ratio method at Kīlauea Volcano, Hawaíi, during a period of sustained inflation

    NASA Astrophysics Data System (ADS)

    Hager, S. A.; Gerlach, T. M.; Wallace, P. J.

    2008-11-01

    The emission rate of carbon dioxide escaping from the summit of Kīlauea Volcano, Hawaíi, proved highly variable, averaging 4900 ± 2000 metric tons per day (t/d) in June-July 2003 during a period of summit inflation. These results were obtained by combining over 90 measurements of COSPEC-derived SO 2 emission rates with synchronous CO 2/SO 2 ratios of the volcanic gas plume along the summit COSPEC traverse. The results are lower than the CO 2 emission rate of 8500 ± 300 t/d measured by the same method in 1995-1999 during a period of long-term summit deflation [Gerlach, T.M., McGee, K.A., Elias, T., Sutton, A.J. and Doukas, M.P., 2002. Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir. Journal of Geophysical Research-Solid Earth, 107(B9): art. no.-2189.]. Analysis of the data indicates that the emission rates of the present study likely reflect changes in the magma supply rate and residence time in the summit reservoir. It is also likely that emission rates during the inflation period were heavily influenced by SO 2 pulses emitted adjacent to the COSPEC traverse, which biased CO 2/SO 2 ratios towards low values that may be unrepresentative of the global summit gas plume. We conclude that the SO 2 pulses are consequences of summit re-inflation under way since 2003 and that CO 2 emission rates remain comparable to, but more variable than, those measured prior to re-inflation.

  16. Emissions reductions from expanding state-level renewable portfolio standards.

    PubMed

    Johnson, Jeremiah X; Novacheck, Joshua

    2015-05-01

    In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power. PMID:25884101

  17. Emissions reductions from expanding state-level renewable portfolio standards.

    PubMed

    Johnson, Jeremiah X; Novacheck, Joshua

    2015-05-01

    In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal