We also find that a hydrogen network connecting renewables, power-to-X hubs, industrial centres and cavern storage sites could be supported by considerable amounts of gas pipeline retrofitting.

Between 64% and 69% of the hydrogen network uses repurposed gas pipelines.

This is good news because the doubling of power grid capacities seen in some scenarios is very ambitious, given limited public support for new transmission projects.

A hydrogen network could at least partially compensate a lack of power grid infrastructure.

But our findings also show that neither electricity nor hydrogen network expansion are truly essential to achieve net-zero emissions in Europe, without impacting costs too much, even without energy imports.

Other technologies compensate: more storage and renewables closer to demand centres.

The combined net benefit of H2 and power grid expansion beyond today’s levels is ~70 bn€/a (~10% of system costs).

Power grid expansion can lower costs by 6-8%, whereas the H2 network benefit is lower (2-3%). In any case, system cost savings largely outweigh the network costs.