Electricity-prioritized hydrogen co-production through renewable-grid integration: A techno-economic assessment

Renewable electricity expansion intensifies grid-balancing challenges, while green hydrogen remains constrained by high production costs. This study evaluates an electricity-prioritized operating approach in which renewable electricity is first sold to the grid, and the remaining power is used for alkaline water electrolysis. Hourly techno-economic simulations were conducted for photovoltaic, wind, and hybrid systems using Korean resource and demand data, considering grid sales, capacity scaling, dispatch, policy conditions, and multiyear variability. Grid-connected electricity sales reduced the levelized cost of hydrogen by 42.51% for photovoltaic systems and 37.61% for hybrid systems relative to off-grid operation. Hybrid systems reduced hydrogen-output variability by 65.20% compared with wind-only systems, while grid-connected wind systems increased hydrogen production by 68.09%. Under favorable electricity-price and renewable-energy-certificate assumptions, photovoltaic and hybrid systems achieved costs below 1 USD/kg. Overall, electricity-prioritized hydrogen co-production improves cost, productivity, and operational stability across diverse variable renewable generation conditions, strengthening the competitiveness of green hydrogen.