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| 1 |
ID:
117220
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| Publication |
2013.
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| Summary/Abstract |
Electricity generation presently contributes approximately 30% of United Kingdom (UK) carbon dioxide (CO2) emissions (Alderson et al., 2012 and Parliamentary, 2007), the principal 'greenhouse gas' (GHG) having an atmospheric residence time of about 100 years (Hammond, 2000). This share mainly arises from the use of fossil fuel (coal and natural gas) combustion for this purpose. Changes in atmospheric concentrations of GHGs affect the energy balance of the global climate system. Human activities have led to quite dramatic increases since 1950 in the 'basket' of GHGs incorporated in the Kyoto Protocol; concentrations have risen from 330 ppm to about 430 ppm currently (IPCC, 2007). Prior to the first industrial revolution in the 18th Century the atmospheric concentration of 'Kyoto gases' was only some 270 ppm. The cause of the observed rise in global average near-surface temperatures over the second half of the 20th Century has been a matter of dispute and controversy. But the most recent (2007) scientific assessment by the Intergovernmental Panel on Climate Change (IPCC) states with 'very high confidence' that humans are having a significant impact on the global warming (IPCC, 2007). They argue that GHG emissions from human activities trap long-wave thermal radiation from the Earth's surface in the atmosphere (not strictly 'greenhouse' phenomena), and that these are the main cause of rises in climatic temperatures. In order to mitigate anthropogenic climate change, the Royal Commission on Environmental Pollution in the UK (RCEP, 2000) recommended at the turn of the Millennium a 60% cut in UK CO2 emissions by 2050. The British Government subsequently set a tougher, legally binding target of reducing the nation's CO2 emissions overall by 80% by 2050 in comparison to a 1990 baseline ( Department of Trade and Industry [DTI], 2007 and Climate, 2008).
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| 2 |
ID:
117228
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| Publication |
2013.
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| Summary/Abstract |
Electricity generation contributes a large proportion of the total greenhouse gas emissions in the United Kingdom (UK), due to the predominant use of fossil fuel (coal and natural gas) inputs. Indeed, the various power sector technologies [fossil fuel plants with and without carbon capture and storage (CCS), nuclear power stations, and renewable energy technologies (available on a large and small {or domestic} scale)] all involve differing environmental impacts and other risks. Three transition pathways for a more electric future out to 2050 have therefore been evaluated in terms of their life-cycle energy and environmental performance within a broader sustainability framework. An integrated approach is used here to assess the impact of such pathways, employing both energy analysis and environmental life-cycle assessment (LCA), applied on a 'whole systems' basis: from 'cradle-to-gate'. The present study highlights the significance of 'upstream emissions', in contrast to power plant operational or 'stack' emissions, and their (technological and policy) implications. Upstream environmental burdens arise from the need to expend energy resources in order to deliver, for example, fuel to a power station. They include the energy requirements for extraction, processing/refining, transport, and fabrication, as well as methane leakage that occurs in coal mining activities - a major cotribution - and from natural gas pipelines. The impact of upstream emissions on the carbon performance of various low carbon electricity generators [such as large-scale combined heat and power (CHP) plant and CCS] and the pathways distinguish the present findings from those of other UK analysts. It suggests that CCS is likely to deliver only a 70% reduction in carbon emissions on a whole system basis, in contrast to the normal presumption of a 90% reduction. Similar results applied to other power generators.
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| 3 |
ID:
109625
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2011.
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| Summary/Abstract |
Biofuels have been identified as a potential short-term solution for reducing greenhouse gas (GHG) emissions from road transport. Currently, '1st generation' biofuels are produced from food crops, but there are concerns with the indirect effects of utilising edible crops for fuel. There is increased interest in producing '2nd generation' biofuels from woody crops and straw, as these can be grown on lower grade land or do not compete directly with food. In order to ensure that biofuels actually deliver emission savings, the overall GHG balance of producing them must be calculated accurately, and compared with conventional fossil fuels. The GHG balance can vary significantly however, depending on biomass type, the production processes, the indirect effects, and also by the method by which the GHG emission balance is calculated. Currently, in the UK, there are three main GHG methodologies that potentially affect biofuel producers. Each has a different approach to measure GHG emissions from biofuel production, and each provides a different result, causing difficulties for policy makers. This study performs a partial life cycle assessment for bioethanol production from wheat grain and wheat straw to demonstrate the variability of the results between methodologies.
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| 4 |
ID:
111075
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2012.
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| Summary/Abstract |
Energy analysis, environmental life-cycle assessment (LCA) and economic appraisals have been utilised to study the performance of a domestic building integrated photovoltaic (BIPV) system on a 'whole systems' basis. Energy analysis determined that the system paid back its embodied energy in just 4.5 years. LCA revealed that the embodied impacts were offset by the electricity generated to provide a net environmental benefit in most categories. Only carcinogens, ecotoxicity and minerals had a small net lifetime burden. A financial analysis was undertaken from the householder's perspective, alongside cost-benefit analysis from a societal perspective. The results of both indicated that the systems are unlikely to pay back their investment over the 25 year lifetime. However, the UK is in an important period (2010/11) of policy transition with a move away from the 'technology subsidies' of the Low Carbon Buildings Programme (LCBP) and towards a 'market development policy' of feed-in tariffs. Representing the next stage on an innovation S-curve this is expected to facilitate rapid PV uptake, as experienced in countries such as Germany, Denmark, and Spain. The results of the present study clearly demonstrate the importance of the new government support scheme to the future uptake of BIPV.
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