Environmental assessment of IGCC power plants with pre-combustion CO2 capture by chemical & calcium looping methods

Abstract

The environmental impact using Life Cycle Assessment (LCA) of coal-based IGCC power plants with carbon capture based on chemical & calcium looping is evaluated in the present work. The two IGCC carbon capture cases use calcium-based CO2 sorbents and iron-based oxygen carriers and they are compared, in term of technical performance (e.g. net power output, energy efficiency, carbon capture rate, CO2 emissions) and environmental performance, to the benchmark case without CO2 capture. The gasification-based power plants produce 440–610 MWe net power with a carbon capture rate higher than 90%. The system boundaries considered in the LCA are: (i) integrated gasification combined cycle with CO2 capture, (ii) raw materials extraction and transport and (iii) carbon dioxide compression, transport and storage. Several environmental impact categories were calculated and compared within the LCA framework. The most significant environmental indicators were: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and abiotic depletion potential (ADP fossil). The best value for GWP, 338.73 kg CO2 equivalents/MWh, was obtained for iron-based chemical looping case. The best value for EP was obtained for the calcium-looping case (1461.97 kg PO43− equivalents/MWh). AP and ADPfossil has the lowest impact in the benchmark case (without CCS).