A gridded inventory of anthropogenic hydrogen emissions in Europe

Hydrogen (H₂) is increasingly perceived as critical to the transition to a low-carbon economy, particularly in Europe, where ambitious climate targets require drastic reductions in greenhouse gas emissions. However, hydrogen emissions are not included in current reporting obligations, and their environmental impact remains underexplored. This study provides a first gridded inventory of anthropogenic hydrogen emissions across Europe, combining bottom-up estimates with spatially resolved activity data. In 2022, emissions were about 327 ktH₂/year (276-378 ktH₂/year). The largest sources are internal combustion engines in road transport (∼38%) and residential wood combustion (∼35%). By contrast, emissions from the hydrogen value chain are smaller, around 83 ktH₂/year (32-133 ktH₂/year). However, hydrogen production is expected to increase 5- to 6-fold by 2050. Under such a scenario, hydrogen emissions from the hydrogen value chain can dominate hydrogen emissions in Europe and could undermine the climate benefits of hydrogen as an energy carrier, if not properly managed.