Life cycle assessment of coal-fired solar-assisted carbon capture power generation system integrated with organic Rankine cycle

Abstract

Pollutant emissions from coal-fired power plants are an important cause of increasingly severe environmental issues, hence realizing clean utilization of energy in such power plants is the key to address environmental problems. Considering a coal-fired power plant (CPGS) as a benchmark, two technical scenarios are proposed: (1) a coal-fired CCS power generation system (CPGS-CCS); and (2) a solar-aided coal-fired power generation system integrating organic Rankine cycle (ORC) and CCS (SCPGS-ORC-CCS). The energy balance and overall performance of three scenarios are investigated with EBSILON, and based on SimaPro 9.0.0.48 software, the life cycle assessment (LCA) of three scenarios is conducted by the ReCiPe Midpoint (H) V1.13 method. The impact of the integrated auxiliary equipment on the environmental categories in the life cycle is examined, and that of key factors on the performance and environment is explored by a sensitivity analysis. The results show that the climate change potential (CCP) is the highest share, and the ozone depletion potential (ODP) is the smallest share among the impact scores of all selected categories of functional units. The integration of CCS, ORC and solar systems results in the following scores of impact categories except for CCP: SCPGS-ORS-CCS > CPGS-CCS > CPGS. Among the three scenarios, CPGS presents the highest CCP score. The coal mining-transportation stage presents the largest contribution to the human toxicity potential (HTP) score, while the operation stage contributes the most to the scores of other impact categories. Sensitivity analysis shows that for SCPGS-ORC-CCS, increasing the service life of equipment, solar radiation intensity and heat ratio can reduce the environmental impact scores. The LCA indicates that CPGS-CCS is a preferred strategy to realize clean energy production. However, comprehensively considering the thermo-economic performance and environmental impact, by selecting appropriate raw materials for auxiliary equipment and sites with sufficient solar radiation intensity, and increasing the life cycle of systems, SCPGS-ORS-CCS is likely to be a more promising strategy in the energy conservation, emission reduction and clean production.