Scenario-based evaluation of renewable hydrogen utilization strategies

Hydrogen currently produced by methane steam reforming (MSR) plays a limited role in the global energy landscape due to its high cost and low overall net energy efficiency compared to other energy options. Electrolysis represents the best renewable option for reducing carbon footprint but is plagued by even higher cost and lower energy efficiency due to the need for two energy conversions between electricity and hydrogen. The photocatalytic (PC) and bio-photocatalytic (PB) production of hydrogen removes the latter limitation on efficiency but is currently only in the very early stages of development with excessive costs and land use. Assessments of performance outcomes were performed based on energy efficiency, CO2 emissions, cost, and land use, technologies, whichreveals significant improvements based on the achievement of their technical potentials. However, even in the most optimistic cases, hydrogen is not expected to provide more than 10–15% of global energy demand by the year 2050, in large part due to transportation and power-conversion costs and logistic constraints. Economic and energy delivery potential of the Power-to-Hydrogen-to-Ammonia-to-Power (P2H2A2P) systems as substitutes for renewable liquid fuels was also evaluatedto determine cost-effectiveness and strategic applicability for decarbonizing energy systems by 2050. The analysis includes solar-based ammonia production in Saudi Arabia for export to the U.S., U.S.-based solar ammonia production for domestic hydrogen use, and direct electrification using U.S. solar power. P2H2A2P schemes allow for logistic and cost advantages where liquid renewable fuels are required (e.g., heavy duty diesel and aviation), and even for production in solar-intense sites for use in consumer-dense/solar- and wind-scarce ones. Improvements in hydrogen production and distribution technologies will provide even more significant benefits in hydrogen non-energy sectors. This paper also quantifies these effects by using the four key performance parameter factors for current and technical potential performance in non-energy hydrogen markets.