Power Generation Enhancement in a Solar Energy and Biomass-Based Distributed Energy System using H₂O/CO₂ Hybrid Gasification

A new solar energy and biomass-based distributed energy system using H₂O/CO₂ hybrid gasification is proposed, and their complementarity to enhance the system’s energy efficiency is investigated and shown. In the system, concentrated solar energy is used to provide heat for biomass gasification; two gasifying agents (H₂O and CO₂) are adopted to enhance syngas yields, and the produced solar fuel is further burned for power production in a combined cycle plant. Results show that CO share in gasification products is remarkably increased with the increment of CO₂/H₂O mole ratio caused by the boudouard reaction with the consumption of fixed carbon, while the H₂ share is decreased; the optimal solar-to-fuel efficiency, 27.88%, is achieved when the temperature and CO₂/H₂O mole ratio are 1050°C and 0.45, respectively. The emission reduction rate of CO₂ in the system under design conditions is reduced by 2.31% compared with that using only H₂O agent. The annual power production of the system is increased by 1.39%, and the thermodynamic and environmental performances are significantly improved. Moreover, an economic assessment is conducted to forecast the technical feasibility of the hybrid gasification technology. This work provides a promising route to improving the thermochemical utilization efficiency of solar energy and solid fuel.