Report examines Europe’s hydrogen infrastructure dilemma

A substantial distribution infrastructure is set to be necessary to accelerate and underline the hydrogen economy and a first question will be whether to repurpose the existing natural gas infrastructure or whether to build new.

There are numerous obvious advantages of repurposing, including substantially reduced costs, increased social acceptance, reduced environmental impact and a more efficient permitting process in comparison to the construction of new pipelines. 

With the intent to establish criteria for repurposing, the transmission operators for gas and hydrogen via their respective associations, ENTSOG and ENNOH, at the request of the European Commission, have completed a study, also drawing on stakeholder input.

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Prerequisite are technical feasibility and safety, with other criteria including N-1 and S-1 for security of supply, economic efficiency via cost assessment and market integration indicators and engagement of the relevant stakeholders.

Though some early publications highlighted that significant technical barriers for repurposing might exist, recent studies show that adequate mitigation options exist for ensuring the techno-economic feasibility of repurposing most natural gas pipelines, according to the report.

Several studies and practical demonstrations also show the capacity of the natural gas network to be used to transport hydrogen safely and reliably. 

Regarding valves, the latest developments mostly show that the conversion of valves is feasible. However, for filters, pre-heaters and gas relief valves, the available information on hydrogen impact is found to be insufficient.

The report adds that some TSOs already have carried out activities to assess their networks’ readiness for repurposing, with some also having commenced repurposing activities and hydrogen filling. Others are currently undertaking or planning such assessments.

It is important that TSOs develop their own processes to assess the technical feasibility of repurposing as existing networks differ regarding their prerequisites. Indeed, due to the absence of a universally recognised approach for repurposing, case-specific technical and safety assessments should be considered. 

Maintaining and enhancing security of energy supply is one of the key objectives of the European Union’s energy policy, along with decarbonisation, diversification and market transparency.

Operators should plan in a coordinated and transparent manner, ensuring that natural gas security of supply is neither compromised nor reduced significantly, and should always apply regulatory requirements.

An economic efficiency assessment starts with a relative cost evaluation considering both natural gas and hydrogen and specifically comparing the configuration that includes a repurposed pipeline. This assessment should include all the related investments in the gas sector to ensure service continuity, with the configuration that implies building a new pipeline.

Potential indicators for affordability are the wholesale price level and for sustainability the existing infrastructure utilisation and development of renewable and low carbon gases.

The report also notes that it is of importance to safeguard the market integration of different regions/countries into the single market. Repurposing should not come at the cost of significant-ly limiting the single market access for a country, even if security of supply is not put at risk when repurposing the cross-border infrastructure.

The findings of the report are due to be taken into account into the TYNDP 2026, as requested in the 11th Energy Infrastructure Forum in Copenhagen in June 2025. The final results on this inclusion will be presented in the 12th Energy Infrastructure Forum in Copenhagen in 2026.