Construction and comprehensive performance analysis of a low-carbon energy system coupling solar energy with reversible solid oxide fuel cells

Reversible solid oxide fuel cells (RSOCs) possess both fuel cell and electrolysis cell operating modes, with their electrolysis mode capable of H₂O-CO₂ co-electrolysis, serving as a novel carbon conversion technology. However, research on their application in distributed energy systems remains insufficient, and their potential for active carbon reduction has yet to be fully explored. This research proposes an integrated energy system coupling RSOCs with solar energy, establishes a system simulation model that includes combined cooling, heating, and power as well as active carbon emission reduction, and investigates the system’s operational characteristics across different seasons, fuel utilization rates, gas sources, and price fluctuations. Additionally, a comprehensive evaluation index considering energy efficiency, environmental benefits, economic performance, and sustainability is proposed. Taking the energy supply of a 2000 m² office building as an example, the maximum daily carbon emission reduction can reach 53 kg in summer when solar radiation is abundant. Furthermore, parametric studies indicate that fuel utilization rates and methane proportions are positively correlated with energy efficiency and exergy efficiency, while the system’s economic performance is most sensitive to electricity prices. The active carbon reduction energy system proposed in this study differs from passive reduction systems by achieving on-site active carbon emission absorption and can flexibly couple with traditional energy systems to meet the low-carbon emission requirements.