Design and optimization of the renewable-driven biomass utilization system for flexible hydrogen carrier production

The global transition to low-carbon energy systems necessitates evaluating the techno-economic and environmental feasibility of renewable-energy-driven biomass utilization systems (BMGSs) for flexible hydrogen carrier production under environmental conditions in South Korea. This study utilizes a multi-objective optimization framework coupled with pinch analysis to optimize energy efficiency, economic viability, and environmental performance, considering total annual cost, self-sufficiency, and CO₂ emissions. The balanced BMGS scenario achieved a self-sufficiency rate of 0.87, producing 177.2 tons of hydrogen and 3,886.9 tons of ammonia annually while minimizing CO₂ emissions (5,081.6 t CO₂/year) and achieving an NPV₂₅ of $15.66 million. The sensitivity analysis of carbon tax rates ($0–$100 per ton of CO₂) revealed that the BMGS_eco scenario, which had the highest CO₂ emissions, exhibited the greatest sensitivity, with a 47 % decline in total economic profit. In contrast, the BMGS_env scenario demonstrated resilience with stable NPV₂₅ values, exhibiting only a 2 % decrease. Notably, the BMGS_grid system, relying solely on grid electricity, became unprofitable at $75/tCO₂. A regional analysis across six South Korean cities revealed significant variations in production costs, with Jeju Island achieving the lowest costs due to its abundant renewable resources.