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| Srl | Item |
| 1 |
ID:
125635
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| Publication |
2013.
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| Summary/Abstract |
Carbon capture and storage (CCS) is an effective technology for the mitigation of greenhouse gas emissions from large-scale fossil fuel use. Nonetheless, it is not yet commercially viable on a large scale, and its inclusion into countries' energy planning agendas depends on realistic assessments of its emission reduction benefits.
The use of CCS leads to energy penalties resulting from direct consumption of additional energy, and results in indirect CO2 equivalent emissions outside plant boundaries, due to both energy consumption and leakages. Accounting for these emissions allows for an evaluation of the mitigation benefits of CCS.
This study performs a life-cycle assessment (LCA), with and without CCS, for a coal-fired power plant located in Brazil. Findings show that when indirect emissions are taken into account, a plant which captures 90% of its CO2 will have its CO2 equivalent emissions capture potential, based on a global warming potential metric with a 100-year time horizon, reduced to 72%. The advantage of the use of carbon capture towards climate change mitigation is reduced mainly as a result of an increase in CH4 emissions, significant in the coal-mining stage, an effect which is only taken into account when a LCA is performed.
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| 2 |
ID:
125654
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| Publication |
2013.
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| Summary/Abstract |
This study shows how the assessment of emissions reductions from CO2 capture is critically dependent on the choice of multi-gas equivalency metric and climate impact time horizon. This has implications for time-sensitive mitigation policies, in particular when considering relative impact of short-lifetime gases. CO2, CH4 and N2O emissions from a coal-fired power plant in Brazil are used to estimate and compare the CO2-equivalent emissions based on standard practice global warming potentials GWP-100 with the less common GWP-50 and variable GWP for impact target years 2050 and 2100. Emission reductions appear lower for the variable metric, when the choice of target year is critical: 73% in 2100 and 60% in 2050. Reductions appear more favorable using a metric with a fixed time horizon, where the choice of time horizon is important: 77% for GWP-100 and 71% for GWP-50. Since CH4 emissions from mining have a larger contribution in the total emission of a plant with capture compared to one without, different perspectives on the impact of CH4 are analyzed. Use of variable GWP implies that CH4 emissions appear 39% greater in 2100 than with use of fixed GWP and 91% greater in 2050.
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