A comparative life cycle impact assessment for solar heat integration in post-combustion carbon capture

Abstract

This study compares the life cycle assessment of conventional post-combustion carbon capture (PCC), solar-assisted PCC, and a novel concept of solar-powered PCC where the rich solvent is independently regenerated in the solar collector field at zero steam demand from the power-plant. Using the OpenLCA software and the EcoInvent database, the environmental impact of the proposed solar-powered PCC is compared with four main scenarios: power-plant only, power-plant with conventional PCC, optimised solar-assisted PCC at a 23 % solar fraction, and the ideal solar-assisted PCC at 100 % solar fraction. It is found that the levelized global warming potential per unit of electricity production for the solar-powered PCC is the lowest among all scenarios (865 kgCO2-eq/MWh). Therefore, the CO2 abatement relative to the base-case scenario is the highest (191 kgCO2-eq/MWh), resulting in a global warming reduction of 18.1 % for the 660MWe and 38.1 % for the 330MWe power-plants, respectively. Moreover, the global warming abatement in the solar-powered PCC scenario proportionally increases with the solar multiple, as the solvent storage requirements are proportionally reduced. However, increasing the solar multiple value does not render the process more economically feasible. Despite the absence of an energy penalty for the power-plant with solar-powered PCC scenario, this advantage alone is not sufficient to offset the economic challenges associated with the large solar collector field and solvent storage installation. Overall, efforts to reduce the cost of CO2 capture using solar-powered PCC will be greatly advantageous for retrofitting this novel technology into existing coal-fired power-plants or industrial plants to mitigate global warming.