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This study aims to evaluate and estimate the environmental impacts of nuclear fuel cycles and to support the decision-making of nuclear energy policy, relating to a selection of environmentally preferred nuclear fuel cycle for the environmentally sound and sustainable development of nuclear energy. To achieve this objective, life cycle assessment (LCA) as an environmental management tool is applied to the nuclear fuel cycle alternatives of a once-through fuel cycle, the direct use of PWR spent fuel in CANDU (DUPIC) cycle and recycling with plutonium and uranium recovery by extraction (PUREX) process. The assessments provide a comparison of the environmental impacts of the three nuclear fuel cycle options and the...
A commonly encountered challenge in emergy analysis is the lack of transformity data for many economic products and services. To overcome this challenge, emergy analysts approximate the emergy input from the economy via a single emergy/money ratio for the country and the monetary price of economic inputs. This amounts to assuming homogeneity in the entire economy, and can introduce serious uncertainties in the results. This paper proposes and demonstrates the use of a thermodynamically augmented economic input-output model of the US economy for obtaining sector-specific emergy to money ratios that can be used instead of a single ratio. These ratios at the economy scale are more accurate than a single economy-wide...
The increased urgency of dealing with mitigation of the looming climate change has sparked renewed interest in the nuclear energy option. There exists a substantial stream of research on the amount of embodied energy and greenhouse gas emissions associated with nuclear generated electricity. While conventional fossil fuelled power plants cause emissions almost exclusively from the plant site, the majority of greenhouse gas emissions in the nuclear fuel cycle are caused in processing stages upstream and downstream from the plant. This paper distils the findings from a comprehensive literature review of energy and greenhouse gas emissions in the nuclear fuel cycle and determines some of the causes for the widely varying...
Biofuels world production has increased sharply in recent years. Oil reserves depletion, the oil high price and the confidence in biofuels “carbon neutrality” are the main causes of this phenomenon. However, claims related to the negative consequences of biofuel programs are frequent; mainly those related to the biofuels/food competition and sustainability. This paper aims to contribute for the development of a framework for sustainability indicators as a tool for performance assessment. The most used indicators to measure the biofuels sustainability are: Life Cycle Energy Balance (LCEB), quantity of fossil energy substituted per hectare, co-product energy allocation, life cycle carbon balance and changes in soil...
Biogas and bio-methane that are based on energy crops are renewable energy carriers and therefore potentially contribute to climate protection. However, significant greenhouse gas (GHG) emissions resulting from agricultural production processes must be considered. Among those, the production and use of fertilizer, and the resulting leaching of nitrous oxide (N2O), are crucial factors. This article provides an integrated life cycle assessment (LCA) of biogas (i.e. bio-methane that has been upgraded and injected into the natural gas grid), taking into account the processes of fermentation, upgrading and injection to the grid for two different types of biogas plants. The analysis is based on different feedstocks from...
One of the first government-sponsored demands for integrated assessment to support decision making in the United States is embodied in the National Environmental Policy Act of 1969 (NEPA). Over the past 25 years, Oak Ridge National Laboratory (ORNL) has supported federal agencies’ in evaluating health and environmental impacts as required by NEPA. Many of ORNL’s efforts have focused on complex, programmatic assessments that break new ground and require and integrate expertise from a wide range of technical disciplines. Examples of ORNL projects that illustrate the use of integrated assessment approaches include environmental documentation for: (1) the Department of the Army’s Chemical Stockpile Disposal Program,...
Biogas and bio-methane that are based on energy crops are renewable energy carriers and therefore potentially contribute to climate protection. However, significant greenhouse gas (GHG) emissions resulting from agricultural production processes must be considered. Among those, the production and use of fertilizer, and the resulting leaching of nitrous oxide (N2O), are crucial factors. This article provides an integrated life cycle assessment (LCA) of biogas (i.e. bio-methane that has been upgraded and injected into the natural gas grid), taking into account the processes of fermentation, upgrading and injection to the grid for two different types of biogas plants. The analysis is based on different feedstocks from...
At the Biomass Research Centre - University of Perugia some LCA studies were carried out on different biomass chains, using a detailed software (Simapro 7.0) and the EcoIndicator 99 model in order to evaluate the global burden. Results showed that EcoIndicator 99 lacks some important features (e.g. freshwater consumption, nutrient emissions into water, soil erosion) that are necessary in evaluating the environmental load of energy crops. Therefore a new LCA methodology, tailored to biomass production, was developed, in which all resources used and emissions into environment were divided into the following impact categories: depletion of abiotic resources, freshwater consumption, climate change, land use, acidification,...
Biofuels world production has increased sharply in recent years. Oil reserves depletion, the oil high price and the confidence in biofuels “carbon neutrality” are the main causes of this phenomenon. However, claims related to the negative consequences of biofuel programs are frequent; mainly those related to the biofuels/food competition and sustainability. This paper aims to contribute for the development of a framework for sustainability indicators as a tool for performance assessment. The most used indicators to measure the biofuels sustainability are: Life Cycle Energy Balance (LCEB), quantity of fossil energy substituted per hectare, co-product energy allocation, life cycle carbon balance and changes in soil...
In Life Cycle Assessment (LCA), normalization calculates the magnitude of an impact (midpoint or endpoint) relative to the total effect of a given reference. The goal of this work is to calculate normalization factors for Canada and the US and to compare them with existing European normalization factors. The differences between geographical areas were highlighted by identifying and comparing the main contributors to a given impact category in Canada, the US and Europe. This comparison verified that the main contributors in Europe and in the US are also present in the Canadian inventory. It also showed that normalized profiles are highly dependent on the selected reference due to differences in the industrial and...
Biofuels world production has increased sharply in recent years. Oil reserves depletion, the oil high price and the confidence in biofuels “carbon neutrality” are the main causes of this phenomenon. However, claims related to the negative consequences of biofuel programs are frequent; mainly those related to the biofuels/food competition and sustainability. This paper aims to contribute for the development of a framework for sustainability indicators as a tool for performance assessment. The most used indicators to measure the biofuels sustainability are: Life Cycle Energy Balance (LCEB), quantity of fossil energy substituted per hectare, co-product energy allocation, life cycle carbon balance and changes in soil...
Biogas and bio-methane that are based on energy crops are renewable energy carriers and therefore potentially contribute to climate protection. However, significant greenhouse gas (GHG) emissions resulting from agricultural production processes must be considered. Among those, the production and use of fertilizer, and the resulting leaching of nitrous oxide (N2O), are crucial factors. This article provides an integrated life cycle assessment (LCA) of biogas (i.e. bio-methane that has been upgraded and injected into the natural gas grid), taking into account the processes of fermentation, upgrading and injection to the grid for two different types of biogas plants. The analysis is based on different feedstocks from...