Techno-economic comparison of biomass combustion and anaerobic digestion systems for hybridization of CSP plants

Abstract

This study aims to investigate comparative techno-economic benefits of biomass combustion and anaerobic digestion systems as retrofit to concentrated solar power (CSP) plants. In this regard, technical parameters of an existing CSP plant currently in operation in Ottana (Italy) have been adopted for analyses. The biomass combustion technology involves direct burning of solid biomass in a furnace, while the anaerobic digestion technology entails biogas production from fruit and vegetable wastes. For the two technologies, the biomass retrofit system was proposed to constantly supply 45% of the nominal thermal power demand of the power block. Results demonstrated the energetic and economic benefits arising from the hybridization of existing CSP plants, both in terms of enhancement of the plant capacity factor and reduction of the cost of energy. Preliminary economic analysis highlighted the direct combustion of solid biomass as a more cost-effective option, while anaerobic digestion biogas plant suffers from substantial installation costs.