Hydrogen emissions from the hydrogen value chain-emissions profile and impact to global warming.

Future energy systems could rely on hydrogen (H) to achieve decarbonisation and net-zero goals. In a similar energy landscape to natural gas, H emissions occur along the supply chain. It has been studied how current gas infrastructure can support H, but there is little known about how H emissions affect global warming as an indirect greenhouse gas. In this work, we have estimated for the first time the potential emission profiles (g CO/MJ H) of H supply chains, and found that the emission rates of H from H supply chains and methane from natural gas supply are comparable, but the impact on global warming is much lower based on current estimates. This study also demonstrates the critical importance of establishing mobile H emission monitoring and reducing the uncertainty of short-lived H climate forcing so as to clearly address H emissions for net-zero strategies.