Hybrid concentrated solar biomass (HCSB) plant for electricity generation in Australia: Design and evaluation of techno-economic and environmental performance

Cost-efficient dispatchable renewable technologies are critical for enabling the energy transition towards 100% renewable generation. One promising example involves the integration of biomass boilers with concentrated solar power (CSP) referred to as hybrid concentrated solar biomass (HCSB) plants. This study evaluates the technical feasibility of a potential plant design for a rice-straw-fed HCSB plant. A case study for the Riverina-Murray region of Australia, a prime area for deployment owing to abundant solar and biomass resources is presented. Based on an assessment of different hybrid concepts, we investigate a solar-biomass hybridization with a concentrated solar tower system. With this hybrid concept, both the CSP and biomass boiler can raise steam to feed the high-pressure turbine enabling greater thermal efficiency. We evaluate HCSB plant performance at four scales: 5, 15, 30 and 50 MWe. Depending on size, HCSB plants reach thermal efficiencies from 21 to 34%. Considering the economic feasibility, assuming an internal rate of return (IRR) of 11%, viable deployment requires an electricity price of AU$ 120-350/MWh. The techno-economic assessment demonstrates advantages compared to standalone CSP plants and highlights the competitiveness of HCSB plants compared to other renewable technologies in Australia. The social and environmental impact assessment highlights additional benefits including local job creation and potential carbon emission mitigation.