Performance evaluation and multi-objective optimization of integrated PV-biomass-rSOC system

Balancing the intermittency of photovoltaic generation with the high capital cost of long-duration storage remains a major challenge for solar-driven power-to-gas systems. This study proposes a novel integrated energy system combining photovoltaic power, a reversible solid oxide cell, and biomass gasification to deliver a stable 1 MW output. Rice husk is adopted as the biomass feedstock, and system performance is evaluated across four representative seasonal days for a site in southwestern China to capture meteorological variability. For the reversible solid oxide cell subsystem, increasing the hydrogen molar fraction from 20% to 60% enhances the reversible efficiency from 88.25% to 89.18%, while excessive current density reduces it by approximately 25%. In the biomass subsystem, the equivalence ratio is the main impact factor, and the hydrogen mole fraction in syngas decreases from 16.4% to 3.8% as the ratio rises from 0.2 to 0.5. Case studies reveal that introducing biomass significantly reduces the required capacities of the photovoltaic array, the reversible solid oxide cell stack, and hydrogen storage. At 50% biomass contribution, the payback period shortens from over 19 years to approximately 12 years compared with the standalone photovoltaic and reversible solid oxide cell configuration. An elitist non-dominated sorting genetic algorithm coupled with a similarity-to-ideal-solution-based decision-making method identifies the recommended configuration, achieving a net present value of 9.17 M$ at 13.28% system efficiency. The proposed configuration provides a robust and economically viable pathway for reliable power supply in high-renewable energy systems.