Hybrid biomass and natural gas combined cycles: Energy analysis and comparison between different plant configurations

The research community has been investigating the integration of biomass into power plants to foster the energy transition to renewables and reduce the dependence on fossil fuels. The aim of the work is to evaluate the energy performance of different combined cycle configurations fueled by natural gas and lignocellulosic biomass, based on biomass gasification and direct combustion of biomass. In the former case, the plant is cofired (COF) with natural gas and syngas. In the latter, two plant configurations were compared: conventional Post-Combustion (PC) and Integrated Fired Recuperated Combined Cycles (BIFRCC), where post-combustion is used to increase the temperature of the air leaving the compressor. The capacity of the systems to integrate biomass was compared with conventional biomass-only plants. The influence of the biomass share has been studied on the main performance indicators: global and biomass efficiency; electrical power increase due to biomass addition; carbon dioxide emissions. An optimization was carried out to identify the most suitable plant configuration and the proper biomass fraction to achieve a trade-off between the need to maintain high global efficiency and high biomass integration. The BIFRCC system has proven to be the most appropriate, with a 35.3% biomass feed ratio and a 41.8% biomass efficiency, significantly higher than conventional steam plants (30% maximum efficiency).