Potential and economic viability of green hydrogen production from seawater electrolysis using renewable energy in remote Japanese islands

Remote island power systems face high equipment costs when introducing renewable energy technologies. Lowering input costs is essential for any setup, but it is especially important for these integrated systems. Electrolysis of seawater is a good option for islands with abundant seawater resources since the green hydrogen produced may be used to create power and excess green hydrogen and Sodium hypochlorite as a by-product can be sold to reduce costs. This study compares three cases. Case 1 mixes solar, wind, and batteries to satisfy load needs. Cases 2 and 3 are based on Case 1 and apply to a seawater electrolysis plant. Case 2 does not account chemical product earnings, whereas Case 3 does. Total cost of the power system and CO₂ total emissions were employed as optimization metrics, using k-means to simplify annual data and MILP to model optimal operation and capacity. Case 3 cuts costs by 16.6% and CO₂ by 13.2% compared to Case 1. The initiative proposes producing and selling green hydrogen and sodium hypochlorite on remote islands by electrolyzing seawater to reduce carbon emissions and costs.