Flexible electrolysis in future energy systems - a comparison of perspectives in the US and the EU

The role of hydrogen in future energy systems is uncertain due to a wide range of factors. This paper lays out the current trends, state of the art, and future perspectives for flexible production of an energy carrier that is crucial to the decarbonisation of hard-to-abate sectors. The approach of the paper has been to compare current projects and studies of the technological progress of electrolysis, investment trends and energy system scenarios. This is discussed in a holistic comparison between two large regions: the EU and the US - with focus on hydrogen supply and policies. We find large discrepancies between these regions, especially in expectations of renewable energy and infrastructure build-out. However, in both regions, a significant capacity of electrolysers will be required by 2050 to reach net-zero emissions and in both regions, flexible operation of electrolysers with 3-5000 h of operation is required to facilitate integration of renewable energy. Thus, a large discrepancy between announced projects and future needs is evident, highlighting the demand for policies to encourage investments. Here, a fixed subsidy as proposed in the US may promote fast investments, while auctions as implemented in the EU may provide cost-efficient, but potentially slower.