Up-to-date life cycle assessment and comparison study of clean coal power generation technologies in China

摘要

China has become the primary energy consumer in the world, consuming 48.2% of the world's coal in 2010. Of this percentage, 48.0% of China's coal consumption is used by the power generation industry, which causes unavoidable environmental problems in the country. This paper presents complete life cycle modeling and a comparative assessment of current clean coal power generation technologies in China, including a state-of-the-art commercial ultra super-critical system. In this study, a life cycle assessment (LCA) is adopted for energy and environment analysis, followed by a brief economic discussion. Incorporating up-to-date data and country-specific situations, the present work covers all upstream stages of the electricity life cycle before final consumption: coal mining, coal transportation, and coal power generation. The modeling results show that ultra super-critical systems (USC) have the highest life cycle energy efficiency due to the highest net generating efficiency and the lowest plant auxiliary power consumption among the cases examined. The global warming potential (GWP) scores show reverse dependencies of net generating efficiency. An integrated gasification combined cycle (IGCC) was demonstrated to be the cleanest technology and has the lowest scores in most of the life cycle impact categories, in particular in acidification potential (AP) and photo-oxidant formation potential (POCP). IGCC ranks as the highest in capital costs due to its complexity, while USC and super-critical systems are among the lowest in capital cost because of their commercialization in China. Evaluation of coal power generation combined with carbon capture and sequestration (CCS) shows that the CCS technologies can reduce the total life cycle CO2 emission from coal power plants substantially, although higher levels of CO2 are generated from the extra energy consumption by the CCS.