Electrolytic hydrogen production; how green must green be?

Abstract

Electrolytic hydrogen from renewable sources is central to many nations’ net-zero emission strategies, serving as a low-carbon alternative for traditional uses and enabling decarbonization across multiple sectors. Current stringent policies in the EU and US are set to soon require hourly time matching of renewable electricity generation used by electrolyzers, aimed at ensuring that hydrogen production does not cause significant direct or indirect emissions. While such requirements enhance the “green credentials” of hydrogen, they also increase its production costs. A modest relaxation of these requirements offers a practicable route for scaling up low-carbon hydrogen production, optimizing both costs and emission reductions. Moreover, in jurisdictions with credible and near-to-medium-term decarbonization targets, immediate production of electrolytic hydrogen utilizing grid electricity would have a lifetime carbon intensity comparable to or even below blue hydrogen and very significantly less than that of diesel, emphasizing the need to prioritize rapid grid decarbonization of the broader grid.