Repurposing existing gas infrastructure to pure hydrogen: ACER finds divergent visions of the future

The European Commission’s hydrogen strategy acknowledges the potential future need for transporting hydrogen over long distances throughout Europe. Two main options are considered for connecting supply and demand by transporting hydrogen:

• building new hydrogen-carrying pipelines or
• repurposing existing natural gas pipelines for transporting pure hydrogen.

In order to assess these options, ACER reviewed more than 20 studies focusing on the technical and the cost aspects of repurposing existing gas infrastructure to pure hydrogen. The analysed studies range across various sources and stakeholders, including the gas industry, multi-partner hydrogen initiatives, industry partnerships, academia, think tanks, and others. As a result, ACER developed a summary paper on the technical possibilities for repurposing, based on these available studies. The paper also offers a reflection on the technical and hydrogen market conditions that could trigger the repurposing of natural gas pipelines to pure hydrogen.

What are the main findings?

• Repurposing is feasible and cheaper than building from scratch: as a rule-of-thumb, repurposing does not present insurmountable technical challenges and is cheaper than building new pure hydrogen networks.

• Studies also draw attention to the suitability of salt cavern facilities for storing hydrogen, noting that these facilities are geographically clustered in selected areas in a few EU Member States.

• Ways of hydrogen transportation: similarly to natural gas, trucks and ships can also transport pure hydrogen. In all cases, distance and volume are the main drivers determining the most cost-efficient mode of transportation. However, at this time, transporting pure liquefied hydrogen by ship is not cost-efficient. Shipping hydrogen as a constituent of ammonia appears to be considerably cheaper.

• Future pure hydrogen networks: studies offer divergent visions of the future extent of pure hydrogen networks. These visions range from a large-scale, pan-European backbone transmission infrastructure primarily based on repurposed natural gas networks, to regional, cluster-like systems handling hydrogen supply and demand in closer geographic proximity. Several studies conclude that, based on industrial hydrogen demand, technology and cost assumptions, there is no indication that a large-scale pan-European hydrogen network would be justified.

• Repurposing to hydrogen may be conditional on:

  1. the presence of loop (parallel) lines in natural gas pipeline systems, so that at least one string could be repurposed to pure hydrogen,

  2. ensuring security of natural gas supply to consumers during the conversion phase to pure hydrogen,

  3. hydrogen market uptake in the area serving a pure hydrogen corridor.

It is uncertain when and where these conditions for repurposing would be met across Europe, and whether they will be met at all.

Following a cautious approach in the implementation phase of pure hydrogen corridors seems to be a reasonable strategy, where repurposing would be triggered by compelling hydrogen market commitments and demand expectations. 

The review is provided on a “best effort” basis and should be seen as a “live reference document”, which may need to be further updated as more knowledge about the future of hydrogen networks emerges. 

ACER and energy regulators will continue discussing the repurposing outlook and stand ready to exchange views with all stakeholders, with the goal of delivering on the decarbonisation targets, as well as ensuring cost-efficient and cost-effective solutions to the benefit of energy consumers.  

Access the Review.