Environmental consequences of an ultra-low emission retrofit in coal-fired power plants from a life cycle perspective

To make coal-fired power generation more environmentally friendly,China has initiated a series of ultra-low emission ret-rofits to the air pollution control(APC)system of the existing power plants.In this study,a life cycle assessment(LCA)is conducted to analyze the environmental net benefits for the typical ultra-low emission retrofit of a 1000 MW power plant.The key processes,substances,and APC devices are verified and discussed.The results confirm that the retrofit effectively decreases the environmental stress of acidification potential(AP),eutrophication potential(EP),and photochemical ozone creation potential(POCP)by 69%-79%,which can be attributed to significantly reduced emissions at the stack.However,the retrofit has also increased other impact categories by 24%-79%,primarily due to the consumption of additional elec-tricity and adsorbents.The retrofit of selective catalytic reduction,electrostatic precipitator(ESP),and wet limestone flue gas desulfurization devices has a dominant effect on the impacts of EP,human toxicity potential(HTP),and AP.A newly installed wet ESP shows some environmental benefits(only for AP),but causes considerable burdens,in particular for the investigated impact categories global warming potential(GWP),marine aquatic ecotoxicity(MAETP),and abiotic depletion fossil(ADP fossil).The obtained results indicate that the hidden environmental consequences,which are associated with the production of energy and materials,need to be examined more comprehensively to inform the development of ultra-low emission technologies and strategies effectively.