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Carbon Dioxide Emissions (carbon + dioxide_emission)
Selected AbstractsThe impacts of Miscanthus×giganteus production on the Midwest US hydrologic cycleGCB BIOENERGY, Issue 4 2010ANDY VANLOOCKE Abstract Perennial grasses are being considered as candidates for biofuel feedstocks to provide an alternative energy source to fossil fuels. Miscanthus×giganteus (miscanthus), in particular, is a grass that is predicted to provide more energy per sown area than corn ethanol and reduce net carbon dioxide emissions by increasing the storage of carbon belowground. Miscanthus uses more water than Zea mays (maize), mainly as a result of a longer growing season and higher productivity. Conversion of current land use for miscanthus production will likely disrupt regional hydrologic cycles, yet the magnitude, timing, and spatial distribution of effects are unknown. Here, we show the effects of five different scenarios of miscanthus production on the simulated Midwest US hydrologic cycle. Given the same historic precipitation observations, our ecosystem model simulation results show that on an annual basis miscanthus uses more water than the ecosystems it will likely replace. The actual timing and magnitude of increased water loss to the atmosphere depends on location; however, substantial increases only occur when miscanthus fraction cover exceeds 25% in dry regions and 50% in nearly all of the Midwest. Our results delineate where large-scale land use conversion to perennial biofuel grasses might deplete soil water resources. Given the fact that some watersheds within the Midwest already have depleted water resources, we expect our results to inform decisions on where to grow perennial grasses for biofuel use to ensure sustainability of energy and water resources, and to minimize the potential for deleterious effects to water quantity and quality. [source] Carbon stored in human settlements: the conterminous United StatesGLOBAL CHANGE BIOLOGY, Issue 1 2010GALINA CHURKINA Abstract Urban areas are home to more than half of the world's people, responsible for >70% of anthropogenic release of carbon dioxide and 76% of wood used for industrial purposes. By 2050 the proportion of the urban population is expected to increase to 70% worldwide. Despite fast rates of change and potential value for mitigation of carbon dioxide emissions, the organic carbon storage in human settlements has not been well quantified. Here, we show that human settlements can store as much carbon per unit area (23,42 kg C m,2 urban areas and 7,16 kg C m,2exurban areas) as tropical forests, which have the highest carbon density of natural ecosystems (4,25 kg C m,2). By the year 2000 carbon storage attributed to human settlements of the conterminous United States was 18 Pg of carbon or 10% of its total land carbon storage. Sixty-four percent of this carbon was attributed to soil, 20% to vegetation, 11% to landfills, and 5% to buildings. To offset rising urban emissions of carbon, regional and national governments should consider how to protect or even to increase carbon storage of human-dominated landscapes. Rigorous studies addressing carbon budgets of human settlements and vulnerability of their carbon storage are needed. [source] A review on energy, economical, and environmental benefits of the use of CHP systems for small commercial buildings for the North American climateINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2009P. J. Mago Abstract The use of combined heating and power (CHP) systems to produce both electricity and heat is increasing rapidly due to their high potential of reducing primary energy consumption (PEC), cost, and emissions in domestic, commercial, and industrial applications. In addition to producing both electricity and heat, CHP systems can be coupled with vapor compression systems to provide cooling. This paper analyzes a natural gas engine CHP system together with a vapor compression system for different American climate zones. Performance is measured in terms of operational costs, PEC, and carbon dioxide emissions as a percent of a reference building. The objective of this paper is to compare the performance of a CHP system operating 24,h a day with a system that only operates during typical office hours. Furthermore, the system is optimized based on reducing PEC, minimizing costs, and reducing emissions. In addition, the benefits of CHP systems based on the Energy Star program and the Leadership in Energy and Environmental Design (LEED) program are presented. Results show that, in general, it is more beneficial to operate the CHP system during typical office hours than to operate the system 24,h a day. Also, the CHP system performance strongly depends on the location where it is installed. In addition to reductions in cost, primary energy, and emissions, CHP systems can help achieve the Energy Star label for commercial office buildings and help obtain LEED points that go toward achieving LEED certification status. Copyright © 2009 John Wiley & Sons, Ltd. [source] Second law analysis of a natural gas-fired gas turbine cogeneration systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2009B. V. Reddy Abstract The influence of operating conditions such as reheat, intercooling, ambient temperature and pressure ratio are analyzed from a second law perspective on the performance of a natural gas-fired gas turbine cogeneration system. The effect of these operating parameters on carbon dioxide emissions is also discussed. The second law efficiency of gas turbine cogeneration system increases markedly with reheat option. Higher pressure ratios lead to decreased second law cogeneration efficiency but this effect can be reduced with a higher level of reheat option. The effect of intercooling on second law efficiency is strongly related to pressure ratio with higher pressure ratios significantly decreasing efficiency. The second law efficiency is not so sensitive to the environment temperature for levels of reheat or intercooling greater than 50%. Copyright © 2009 John Wiley & Sons, Ltd. [source] The Value of Remanufactured Engines: Life-Cycle Environmental and Economic PerspectivesJOURNAL OF INDUSTRIAL ECOLOGY, Issue 1-2 2004Vanessa M. Smith Remanufacturing restores used automotive engines to like-new condition, providing engines that are functionally equivalent to a new engine at much lower environmental and economic costs than the manufacture of a new engine. A life-cycle assessment (LCA) model was developed to investigate the energy savings and pollution prevention that are achieved in the United States through remanufacturing a midsized automotive gasoline engine compared to an original equipment manufacturer manufacturing a new one. A typical full-service machine shop, which is representative of 55% of the engine remanufacturers in the United States, was inventoried, and three scenarios for part replacement were analyzed. The life-cycle model showed that the remanufactured engine could be produced with 68% to 83% less energy and 73% to 87% fewer carbon dioxide emissions. The life-cycle model showed significant savings for other air emissions as well, with 48% to 88% carbon monoxide (CO) reductions, 72% to 85% nitrogen oxide (NOx) reductions, 71% to 84% sulfur oxide (SOx) reductions, and 50% to 61% nonmethane hydrocarbon reductions. Raw material consumption was reduced by 26% to 90%, and solid waste generation was reduced by 65% to 88%. The comparison of environmental burdens is accompanied by an economic survey of suppliers of new and remanufactured automotive engines showing a price difference for the consumer of between 30% and 53% for the remanufactured engine, with the greatest savings realized when the remanufactured engine is purchased directly from the remanufacturer. [source] Systems approach to reducing energy usage and carbon dioxide emissionsAICHE JOURNAL, Issue 9 2009David Glasser First page of article [source] First assessment of methane and carbon dioxide emissions from shallow and deep zones of boreal reservoirs upon ice break-upLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 1 2006Éric Duchemin Abstract Most studies dealing with greenhouse gas (GHG) emissions from large boreal reservoirs were conducted during the ice-free period. In this paper, the potential methane (CH4) and carbon dioxide emissions are estimated for two hydroelectric reservoirs, as well as for a small experimental reservoir from boreal latitudes (northern Quebec, Canada) at the ice break-up event through diffusion (diffusive fluxes) and release of bubbles (bubbling fluxes). The results of this preliminary study suggest that the winter diffusive fluxes at the air,water interface of the sampled reservoirs represent < 7% of their cumulative carbon emissions during the ice-free period. Furthermore, the release upon ice-break of CH4 bubbles accumulated under the ice cover during the winter could represent 2% of the summer carbon emissions from hydroelectric reservoirs in northern Quebec. The results presented herein suggest that the GHG emissions upon ice break-up from the boreal reservoirs investigated are a small, but non-negligible, component of their annual GHG emissions. [source] Fretting fatigue strength of SCM435H steel and SUH660 heat-resistant steel in hydrogen gas environmentLUBRICATION SCIENCE, Issue 3 2008M. Kubota Abstract Utilisation of hydrogen is expected to be one of the solutions against the problems of exhaustion of fossil fuels and reduction of carbon dioxide emissions. Evaluation of the materials for hydrogen utilisation machines is required. The objectives of this study are the characterisation of fretting fatigue strength of low-alloy steel SCM435H and heat-resistant steel SUH660, and the validation of effectiveness of nitriding in hydrogen gas environment. Fretting fatigue tests were conducted up to 3 × 107 cycles. The decrease of fretting fatigue strength in hydrogen gas environment was found at the long-life region exceeding 107 cycles. The amount of the decrease of the fretting fatigue limit at 3 × 107 cycles was 11% for SCM435H and 15% for SUH660. However, at the stress level above the fretting fatigue limit in air, the finite life in hydrogen gas increased more than that in air. The cause of extension of fatigue life was the delay of start of stable crack propagation. Fretting fatigue crack, which was smaller than 200,µm in length, consumed approximately 60% of the fatigue life in hydrogen gas environment. Fretting fatigue crack was steadily propagated after the test was started in air. Observations of the fretted surface showed that the fretting wear process in hydrogen gas environment was dominated by adhesion. Tangential force coefficient was higher in hydrogen gas environment than that in air. It is considered that the adhesion has a close relation to crack initiation in hydrogen gas environment, and as a result, the failure of specimen occurred at a lower stress level comparing the fretting fatigue limit in air. Copyright © 2008 John Wiley & Sons, Ltd. [source] How Useful Is the Genuine Savings Rate as a Sustainability Indicator for Regions within Countries?THE AUSTRALIAN ECONOMIC REVIEW, Issue 4 2005Australia, Queensland Compared This article shows how macroeconomic indicators of sustainable development can be applied to the Queensland economy. While recognising the complex and contentious theoretical and practical issues in deriving the Genuine Savings Rate (GSR) to serve as such an indicator, we use the World Bank's methodology, which includes only mineral depletion, deforestation and carbon dioxide emissions as environmental terms, to estimate GSRs for Queensland for the period 1989 to 1999, and compare these to World Bank estimates of Australia's GSR for the same period. We find that Queensland has a higher rate of natural resource depletion and a lower GSR than the whole of Australia. We also examine how well the World Bank GSR performs as a ,headline' measure of overall sustainability, review criticisms of the GSR, and compare its implicit policy implications with those of net state savings, and of the GSR plus a suite of other indicators. [source] Carbon Taxation, Fuel Substitution and Welfare in AustraliaTHE AUSTRALIAN ECONOMIC REVIEW, Issue 1 2000John Creedy This paper examines the potential role for fuel substitution in electricity production in reducing carbon dioxide emissions over a ten-year time horizon. This is achieved by adding fuel substitution to output changes resulting from demand responses arising from a tax on carbon dioxide emissions. A time profile of adjustments is developed. The tax required for Australia to meet a 20 per cent reduction in emissions from 1993 levels is calculated and effects on inequality and social welfare are examined. The paper also examines the potential effect of a subsidy towards the use of low-emission fuels, financed from the carbon tax. A subsidy produces an improvement in emissions abatement and a lower tax required to reach the emissions target. [source] Black gold to green gold: regional energy policy and the rehabilitation of coal in response to climate changeAREA, Issue 1 2009Frances Drake Energy production has come under increasing scrutiny as concerns about energy security and climate change have risen. In the UK changes in government structure and privatisation of the electricity industry have led to the emergence of multi-level governance. This means that decisions on how to reduce carbon dioxide emissions from the electricity-generating sector should no longer be solely a national policy decision. Previous studies have sought to explore how renewable energy may develop under multi-level governance, but this paper pays attention to a traditional fossil fuel source, coal, which is still an important means of electricity generation. Coal is the most abundant fossil fuel and advocates argue that carbon capture and storage techniques could make coal ,clean', paving the way for a long-term, secure and low emission way to produce energy. This study focuses on the Yorkshire and Humber Region, which has had a long association with coal mining and looks at the implications of this as the region seeks to develop a climate change action plan and an energy strategy within the new regional governance structures. The paper argues that the regional networks developed to address climate change are influenced by existing social power structures and alliances. The region as a territorial structure becomes a useful device in promoting national priorities. [source] Climate change: a rational choice politics view,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 3 2009Geoffrey Brennan Reduction in carbon dioxide emissions constitutes a global public good; and hence there will be strong incentives for countries to free ride in the provision of CO2 emission reductions. In the absence of more or less binding international agreements, we would expect carbon emissions to be seriously excessive, and climate change problems to be unsolvable. Against this obvious general point, we observe many countries acting unilaterally to introduce carbon emission policies. That is itself an explanatory puzzle, and a source of possible hope. Both aspects are matters of ,how politics works', i.e. ,public choice' problems are central. The object of this paper is to explain the phenomenon of unilateral policy action and to evaluate the grounds for ,hope'. One aspect of the explanation lies in the construction of policy instruments that redistribute strategically in favour of relevant interests. Another is the ,expressive' nature of voting and the expressive value of environmental concerns. Both elements , elite interests and popular (expressive) opinion , are quasi-constraints on politically viable policy. However, the nature of expressive concerns is such that significant reductions in real GDP are probably not sustainable in the long term , which suggests that much of the CO2 reduction action will be limited to modest reductions of a largely token character. In that sense, the grounds for hope are, although not non-existent, decidedly thin. [source] Global Energy and Environmental Impacts of an Expanding ChinaCHINA AND WORLD ECONOMY, Issue 4 2006Warwick J. McKibbin Q53; Q56; Q58 Abstract China accounts for 10 percent of global energy use and will continue to rely on coal for generating approximately 75 percent of its energy over coming decades. The environmental problems associated with coal burning are a concern for China as well as regionally and globally. The present paper summarizes China's energy structure and likely future energy requirements, while exploring the impact of energy use on air quality, black carbon emission, sulphur dioxide (SO2) emissions, and carbon dioxide emissions. Although China has begun to take action on local environmental problems from energy, there is still much to be done. In particular, the problem of black carbon and carbon dioxide emissions needs to be addressed. The present paper proposes addressing carbon dioxide emissions through a longer-term strategy that acknowledges the need for China to continue to grow without a short-term carbon constraint but with clear pricing of the short-term and long-term cost of carbon dioxide. (Edited by Xiaoming Feng) [source] | |||||||||||||||||||