Effect of Hydrogen Leakage on the Life Cycle Climate Impacts of Hydrogen Supply Chains

Hydrogen is of interest for decarbonizing hard-to-abate sectors because it does not produce carbon dioxide when combusted. However, hydrogen has indirect warming effects. In this work, we conducted a life cycle assessment of electrolysis and steam methane reforming to assess their emissions while considering hydrogen’s indirect warming effects. We find that the primary factors influencing life cycle emissions are the production method and related feedstock emissions, rather than the hydrogen leakage and the indirect warming potential of hydrogen. A comparison between fossil fuel-based and hydrogen-based steel production and heavy-duty transportation showed a reduction in greenhouse gas emissions, of approximately 800 to more than 1400 kgCO ₂ e per tonne of steel and 0.1 to 0.17 kgCO ₂ e per tonne-km of cargo. While any hydrogen production pathway reduces greenhouse gas emissions for steel, this is not the case for heavy-duty transportation. Therefore, we recommend a nuanced approach in choosing application areas for hydrogen.