In a bid to decarbonise its industries and to permanently cut energy import ties with Russia, the European Union (EU) wants to produce and import 20mn tonnes of renewable hydrogen by 2030. Since green hydrogen electrolysers will need be located near often remote large-scale wind farms and solar parks, and the imported green fuel will have to be distributed across the continent, transporting the gaseous fuel to demand centres will be crucial to the success of the hydrogen economy.

Playing into the EU’s hands here is its vast existing gas grid. As the continent strives to become carbon neutral by mid-century, its nations are slowly but surely phasing out gas use and therefore gas infrastructure is at risk of eventually becoming obsolete. This is where the nascent hydrogen market looks to come to the rescue of old pipelines as a number of studies and test cases have shown that gas infrastructure can be adapted to safely transporting hydrogen with little effort.

‘We have had very positive results for converting the existing gas infrastructure to hydrogen. Most of the components are suitable,’ says Julio Garcia-Navarro, Project Coordinator of the HyDelta project, a Dutch public-private partnership testing the potential for transporting hydrogen in gas infrastructure.

Having access to an existing pipeline network is not only convenient from an asset repurposing and time saving perspective, but is also financially attractive. The International Energy Agency (IEA) estimates that adapting an existing gas pipeline to transporting hydrogen is 50–80% cheaper than building a new pipeline.

The conversion of existing gas pipelines is the basis for the development of the so-called European Hydrogen Backbone (EHB) that was initiated in 2021 and which is central to fulfilling Europe’s hydrogen ambitions. From Arctic Sweden to Tarifa in southern Spain and Ireland’s Cork to Romania’s Black Sea coast, by 2040 the EHB plans to span a 53,000 km hydrogen transport network that will be over 60% based on repurposed gas pipelines.

At an estimated investment cost of €80–143bn, hydrogen is expected to flow between production or import locations to demand hubs across five corridors: the North Sea, Nordic and Baltic, East and South-eastern Europe, South-western, and North Africa-Italy.

‘Technically, we do not see challenges that cannot be overcome to convert existing natural gas infrastructure to hydrogen,’ says Martijn Overgaag, Project Director at Guidehouse, a consultancy which has carried out the research underpinning the EHB project.

High pressure
From a technical point of view, most gas pipelines are able to accommodate gaseous hydrogen. The main challenge is that hydrogen, the periodic table’s lightest element, has only one third of the volumetric density of gas. Therefore, compressors are needed to bring the volume of the transported hydrogen up to the gas standard in order to use existing pipelines most efficiently.

Another technical challenge is to prevent hydrogen embrittlement in pipeline steel, a reduction in the ductility of a metal that can cause cracks and holes. In cases where gas pipeline properties are found to be unsuitable for hydrogen transport, operators can apply an internal protection coating or use a pipe-in-pipe solution, although these options can be costly.

HyDelta’s Garcia-Navarro also says that his research has shown hydrogen pipelines will likely require slightly higher maintenance costs because filters keeping out impurities of the pipelines will need to be replaced more frequently.

Case studies have also shown that transporting hydrogen via pipelines is as safe as operating oil and gas infrastructure, which will form the basis of regulation to be applied to hydrogen. ‘From a safety point of view, the safety zones for hydrogen transport in pipelines are not expected to be worse than for natural gas and oil,’ says Charles Renaud-Bezot, Senior Principal Engineer for hydrogen at Norway’s Aker Solutions.

Political support
The EHB has the backing of 31 energy infrastructure operators, many of which are state owned. However, political support for pipeline conversion varies. Areas in north-western Europe (the Netherlands, Germany, Belgium) and southern Europe (Spain, Italy) have seen the strongest governmental support for hydrogen infrastructure, reflected in the fact that these regions are seeing the most advanced projects.

The European fallout with Russia following its invasion of Ukraine and the subsequent reduction of Russian energy imports has given Europe’s hydrogen dreams renewed impetus. Governments have increased budgets for alternative energy projects, including hydrogen, and have eased permitting procedures.

This has helped speed up momentum and, on the ground, the EHB is already starting to take shape. Some noteworthy projects include the German H₂ercules plan spearheaded by utility RWE and gas grid operator OGE, which aims to link green hydrogen production and import sites on the German North Sea coast with demand centres in the west and the south of the country by 2030. Most of the project’s envisaged 1,500 km long hydrogen network involves the conversion of existing gas pipelines.

‘Often, natural gas pipelines already exist that are suitable for conversion. The conversion of such pipelines is technically simpler, cheaper and quicker to realise than new constructions and is therefore a key success factor. That’s why we collaborate with gas grid operators in our projects,’ says an RWE spokesman.

In the neighbouring Netherlands, a traditionally gas-heavy country, the government has set aside €750mn for the creation of a national hydrogen network, which will consist to the tune of 85% of repurposed gas pipelines. ‘This is good for the environment and relatively little new excavation work is required. It is also good for our wallets, because reusing existing infrastructure is much cheaper,’ comments Dutch state-owned gas grid operator Gasunie.

The transmission system operator has already successfully repurposed a 12 km long gas pipeline in the south of the Netherlands, which has been flowing hydrogen from a cracking plant owned by Dow Benelux to a Yara chemical manufacturing site since late 2018.

At the French, German and Luxembourg borders, a cross-country hydrogen network is already being developed with the EHB in mind. A 100 km long hydrogen pipeline across the co-called ‘Grande Région’ will see 70 km of existing gas lines repurposed by 2027, with 60,000 tonnes of hydrogen expected to be transported through the hub by 2030.

Policy progress
Although some projects are starting to take shape, actual investment decisions and shovels in the ground remain few and far between, considering the task at hand within the short timeframe targeted. One major barrier is uncertainty about regulation of the hydrogen market, including who will be mandated to own and operate future hydrogen pipelines.

‘There’s so much unclarity on all the market design tariffs, the gas quality, but also on permitting operations, technical aspects or material qualities. There are many red flags, so it takes time,’ says Magnus Killingland, Segment Lead for hydrogen at consultancy DNV.

In mid-February, the EU published two ‘Delegated Acts’ which set out rules for renewable hydrogen that have, after much delay, given potential investors a better understanding of how regulators assess whether hydrogen produced at a certain site is considered green or not.

‘It is important for project developers, which are often members of the EHB initiative, to decide to invest in the deployment to have certainties around the future use of the pipeline,’ says Guidehouse’s Overgaag, who adds that the ongoing review of the EU Gas Directive should provide guidance on these questions. The review includes, for example, the creation of a European Network of Network Operators for Hydrogen to ensure a future hydrogen grid is well managed and that the fuel will flow across EU borders.

Although some projects are starting to take shape, actual investment decisions and shovels in the ground remain few and far between, considering the task at hand within the short timeframe targeted.

Chicken and egg
Another challenge is what many in the industry refer to as the ‘chicken-and-egg’ problem. It relates to the dilemma around the lack of infrastructure impeding demand development and vice versa. ‘The European Hydrogen backbone is quite ambitious. The development does not depend on the transport infrastructure only, but on the full value chain: producers, transport, end-user. Are end-users ready and will we have enough and cheap hydrogen production in time?’ asks Aker Solutions’ Renaud-Bezot.

Some European industrial users have announced plans to switch to green hydrogen as a means to decarbonise their production processes and as a cost-effective alternative to volatile fossil fuels. But, like network operators, industrial users are also reluctant to make investment decisions in a market that remains to be clearly regulated.

While the ageing gas infrastructure is available and safe to use for the transport of hydrogen, it’s the rest of the hydrogen value chain that needs to follow through on promised supply and demand projects to make the EHB a reality by 2030.