Technological learning and the future of solar H2: A component learning comparison of solar thermochemical cycles and electrolysis with solar PV

This analysis uses component learning curves to investigate the effect of policy support on the future potential of two methods of producing hydrogen using solar energy: solar thermochemical cycles and electrolysis with solar photovoltaics. The impact of policy support for photovoltaics, electrolysis, concentrated solar power, and thermochemical reactors is assessed. The rates of growth of the four technologies are taken as proxies for the degree of policy support. Key assumptions are identified and results are considered over the range of reasonable assumptions. Initially, electrolysis with PV will be the less expensive way to produce solar hydrogen. However, though it is initially more expensive, the thermochemical cycle has greater long-term potential for cost reductions from learning, and it is the faster route to $2/kg hydrogen. Cost reductions in hydrogen from the thermochemical cycles are primarily driven by improvements in the thermochemical reactors, which, due to initially high costs, will only see growth through government support. Thus, policymakers must support the thermochemical cycles through their research, development, and early implementation stages in order to achieve these cost reductions. Though the details change when key parameters are varied over their range of reasonable values, the broad conclusions are unaffected.