Optimizing Biogas-to-Hydrogen Conversion Under the Feed-In Premium Scheme: A Comparative Analysis of Steam Reforming and Electrolysis in an Individual Biogas Plant

The transition toward market-oriented renewable energy policies has increased the demand for flexible operation of biogas plants (BGPs), particularly under Japan’s Feed-in Premium (FIP) scheme. This study evaluates the technical performance and revenue potential of integrating hydrogen production into a dairy-manure-based BGP, focusing on steam reforming (SR) and electrolysis (EL) pathways. An energy system optimization model was developed using the Open Energy Modelling Framework (OEMOF) to simulate coordinated operation of biogas combined heat and power (CHP), hydrogen production, heat supply, and storage under electricity spot market conditions in Hokkaido, Japan. Sensitivity and scenario analyses were conducted to examine hydrogen production behavior, system-level resource allocation, and revenue performance under varying hydrogen prices and FIP levels. The results show that EL enables price-responsive switching between electricity supply and hydrogen production, resulting in dynamic hydrogen output and high sensitivity to conditions. In contrast, SR provides stable hydrogen production through continuous biogas utilization, achieving biogas throughput but limited responsiveness to price fluctuations. A System-level trade-off between conversion flexibility and direct fuel utilization efficiency was identified. These findings indicate that hydrogen pathway selection in farm-scale BGPs should be treated as a system design decision shaped by market exposure, operational objectives, and risk tolerance under the FIP framework.