Comparative evaluation of electrolysis methods for solar-assisted green hydrogen production

The deep decarbonization of the power, industrial, and transportation sectors heavily depends on green hydrogen. However, the widespread adoption of green hydrogen as a clean fuel is hindered by high costs. This study addresses the cost of large-scale solar-assisted green hydrogen production via water electrolysis through a techno-economic analysis. Solar energy was harnessed using concentrated solar power systems. This study presents a detailed design methodology employing real-time solar resource data with 30-min resolution and off-design performance prediction to account for the intermittent nature of solar energy. Western Australia was selected as the solar site, and the solar system was designed to maintain a constant power output of 10 MWe, which was achieved by a solar field and thermal energy storage capacity of 220,000 m2 and 3,990,000 kWh(th), respectively. To evaluate the cost-effectiveness of the electrolysis apparatus, models for each electrolysis process, that is, solid oxide electrolysis, proton exchange membrane, and alkaline electrolysis cell, were developed and validated. The results showed that the costs of green hydrogen with solid oxide, proton exchange, and alkaline cells were 7.86, 13.07, and 14.44, US$/kg-H2 respectively. Despite the high cost of solid oxide cells, the results indicate that large-scale green hydrogen production with solid oxide electrolysis cells is economically viable. These findings are significant for academic and industrial stakeholders to foster the green hydrogen sector in Australia.