Life cycle environmental impact assessment of fuel mix-based biomass co-firing plants with CO2 capture and storage

Highlights: • Developed life cycle assessment model for biomass co-firing power plants with CCS. • Given detailed process-level input-output table based on mass and energy balances. • Co-firing of 25% biomass with coal can achieve near-zero emissions in CCS plants. • Environmental burden shifts significantly as the co-firing ratio. • Uncertainty analysis was carried out for the environmental burden shift. -- Abstract: As a carbon-neutral renewable energy source, biomass co-firing with coal contributes to reducing the carbon intensity of pulverized coal power plants with CO₂ capture and storage; thus, this process significantly reduces the greenhouse gas emissions of the power industry. However, various types of environmental impacts caused by co-firing have hindered the large-scale deployment of this technology. In this study, ten life cycle assessment models were developed based on the Integrated Environmental Control Model and GaBi software to quantify the performance parameters of different power plants and the influence of the co-firing ratio on various environmental impact categories. The system boundaries included raw material acquisition, raw material transport, energy conversion of power plants, CCS and brine treatment. The results indicated that a pulverized biomass/coal co-firing power plant with CCS can achieve near-zero emissions at a co-firing ratio of 25% and negative emissions of 877 kg CO₂-e/MWh from a life-cycle perspective when coal is totally replaced. Co-firing biomass and coal in power plants has a passive impact on seven environmental categories, such as the eutrophication potential and toxicity potential, rather than on the global warming potential, abiotic resource depletion potential and acidification potential. The major causes of environmental burden shifting are energy penalties and indirect emissions from high-energy-consumption processes, especially emissions of N₂O, NH₃ and ethylene oxide released during biomass extraction and solvent preparation. The conclusions and recommendations presented in this paper may have implications for deep decarbonization in other industrial sectors.