Techno-economic-environmental assessment of biomass oxy-gasification staged oxy-combustion for negative emission combined heat and power

Climate change mitigation requires developing low-carbon technologies capable of achieving CO₂ emission reductions at the gigatonne scale and affordable cost. Biomass gasification, coupled with carbon capture and storage, offers a direction to atmospheric CO₂ removal. To compensate for the issues associate with the high-investment requirement of CO₂ removal unit and lower efficiency compared to fossil-based power cycles, this study proposed a conceptual system for combined heat and power, based on biomass oxy-gasification integrated with staged oxy-combustion combined cycle (BOXS-CC). Aspen Plus® is used to develop the process model of the proposed cycle. The results obtained in the techno-economic analysis showed that the net power efficiency of the proposed concept with 50.2 kg/s biomass flowrate was 41.6%, and the heat efficiency was 27.4%, leading to a total efficiency of 69.0%, including CO₂ compression. Moreover, the economic assessment of BOXS-CC revealed that it can achieve a levelised cost of electricity of €21.4/MWh, considering the heat and carbon prices of €46.5/MWh and €40/tCO₂, respectively. Such economic performance is superior compared to fossil fuel power plants without CO₂ capture. The environmental assessment shows that BOX-CC system results in net negative emissions of 766 kg CO₂ eq./MWh_e.