Comparative Assessment of Renewable Hydrogen Production Pathways

The global transition to low-carbon energy systems has intensified interest in hydrogen as a clean energy carrier. Still, the environmental benefits of using hydrogen as a fuel depend greatly on its production process, as conventional fossil-fuel-based methods are associated with significant greenhouse gas emissions. In this regard, hydrogen production from renewable energy (so-called green hydrogen) has emerged as a promising solution for sustainable energy systems. This study evaluates water electrolysis powered by renewable electricity from solar, wind, hydroelectric, and geothermal sources alongside thermochemical and biological hydrogen production from biomass. Solar- and wind-based electrolysis currently offers the most favorable balance between technological maturity, scalability, and cost, with levelized costs ranging from about 3.8 to 11.9 USD/kg H2 depending on resource quality and electricity price. Conversely, biomass-based processes operate more efficiently but face material and sustainability limitations. Emerging technologies (e.g., offshore wind-energy-powered water electrolysis) show significant long-term potential but remain constrained by low maturity. This paper highlights key challenges and future research directions needed to accelerate the transition to a sustainable hydrogen economy.