An optimization model is used to design a hydrogen production system under different constraints for CO2 emissions, focusing on Japan as case of study. Two scenarios were considered: Base scenario, focusing on minimizing cost; and WEC scenario focusing on balancing energy use, water use and CO2 emissions. Domestic natural gas alone is not enough to produce 1 Mt-H2/year and electrolysis is used for all CO2 intensities. For low CO2 intensities, Base scenario uses hydroelectricity and geothermal electricity; while WEC scenario uses solar electricity and wind electricity. Zero-emission hydrogen production needs installed capacities for electrolyzers of 8.45 and 30.3 GW in Base and WEC scenarios, respectively.
Keywords Hydrogen Production System, Hydrogen, Water-Energy-Carbon Nexus, Hydrogen Economy