The second list of Projects of Common Interest (PCIs) marks a significant success for Europe’s Underground Hydrogen Storage (UHS) operators. It sends a clear signal that hydrogen infrastructure is no longer peripheral, but institutionally recognised as central to the Union’s energy transition. This momentum must now be translated into action by systematically improving the investment framework for UHS, both within and beyond PCI-designated projects.
UHS is a pivotal enabler of a decarbonised, affordable, and resilient European energy system. It delivers benefits across power, industry, and mobility, while reinforcing strategic autonomy and long-term energy security. The recognition of UHS under the PCI framework is therefore not the end of the journey, but the foundation on which Europe must now build.
What are PCIs, and why do they matter?
On 1 December 2025, the European Commission granted 235 additional cross-border energy projects the status of Projects of Common Interest (PCIs) and Projects of Mutual Interest (PMIs). PCIs are considered key projects in the EU internal energy market and support climate-neutrality objectives, ensuring that all Europeans have access to affordable, secure, and sustainable energy. PMIs extend this framework to cross-border infrastructure between EU and non-EU countries, aligning external energy links with the Union’s climate and energy goals.
The 2025 list is the second list adopted under the revised Trans-European Networks for Energy (TEN-E) Regulation, which entered into force in 2022. This Regulation represents a decisive pivot away from fossil fuel infrastructure towards low-carbon, resilient, and efficient cross-border solutions compatible with the EU’s 2050 climate-neutrality objective. PCI and PMI lists are adopted every two years, following extensive stakeholder engagement through regional working groups and public consultations, ensuring alignment with both system needs and market realities.
The latest list includes 100 hydrogen projects, of which 20 are underground hydrogen storage projects. This outcome also reflects sustained and coordinated advocacy by members of H2eart for Europe and the wider UHS community, demonstrating that constructive engagement can deliver tangible results at EU level.
PCI and PMI status brings concrete advantages. Selected projects benefit from priority treatment and streamlined permit-granting procedures, with a binding three-and-a-half-year timeline. Environmental assessments are accelerated and better coordinated, and developers are supported by a national ‘one-stop shop’ acting as a single point of contact for permitting. PCIs can also access mechanisms for cross-border cost allocation, ensuring that costs are fairly shared between Member States that benefit from the project. Finally, PCI status unlocks eligibility for financial support under the Connecting Europe Facility (CEF), including grants for studies and construction.
Why underground hydrogen storage is essential
Underground hydrogen storage is fundamental to Europe’s energy sovereignty and system resilience. By enabling large-scale, long-duration storage, UHS reduces dependence on volatile global energy markets and provides a domestic buffer against supply shocks. At the same time, it supports long-term decarbonisation in line with European climate objectives.
From a system perspective, UHS offers an important and efficient pathway to climate neutrality. It enables the optimal integration of renewable electricity by absorbing excess generation during periods of high supply and low demand, avoiding curtailment, and storing energy to manage mid- and long-term supply fluctuations. This reduces the need for costly over-investment in grids, generation, or short-duration storage technologies. In doing so, it lowers overall system costs for consumers and industry alike.
UHS unlocks true sector integration. By linking electricity and hydrogen systems, it enables flexible hydrogen-fired power generation that can stabilise electricity grids during periods of low renewable output, while simultaneously meeting industrial demand for clean molecules. This flexibility will be indispensable as variable renewables become the backbone of Europe’s power system.
UHS also addresses a critical infrastructure gap for scaling clean hydrogen use in industry. Steel, chemicals, refineries, and synthetic fuel production account for the majority of Europe’s future hydrogen demand. Without large-scale, reliable storage solutions, these sectors would not be able to switch to hydrogen at the pace and scale required.
Improving investment conditions: The next priority
The institutional recognition of UHS projects in the PCI framework is a major step in the energy transition. Turning this recognition into a robust pipeline of final investment decisions will determine whether Europe can deliver a resilient, competitive, and climate-neutral energy system. Turning ambition into delivery will depend, among other things, on stronger investment conditions and storage-specific, financial de-risking instruments. Europe’s clean energy transition won’t succeed without innovative solutions and scalable projects for hydrogen infrastructure. H2eart for Europe remains committed to advancing this discussion and to ensuring that hydrogen storage receives the strategic priority it deserves.