Can natural gas infrastructure be repurposed for the hydrogen economy?

Posted: January 21, 2026

Just outside the eastern German town of Baruth/Mark, one small connecting pipe has been receiving truckload after truckload of gaseous hydrogen over the course of several months. The setting may be unglamorous, but the result may prove to be a milestone for the European energy industry. All this hydrogen has been clearing out the natural gas from a stretch of pipeline that will henceforth only be used to carry hydrogen.

The Ostsee-Pipeline-Anbindungsleitung (OPAL) used to be one of two pipelines that brought Nord Stream natural gas from the Baltic into the wider continental network. But the German government has committed to an ambitious national hydrogen strategy involving a core national distribution network. Ultimately, if all goes to plan, OPAL will soon instead bring climate-friendly green hydrogen from the Baltic coast to where German (and Central European) industry needs it.

OPAL’s first 400-kilometer stretch is now ready, but Germany’s ambitions stretch wider. By 2032, its core hydrogen network is supposed to involve hydrogen hubs in every German state, connected by over 9,000 kilometers of active pipeline. As of 2023, the country had just 417 kilometers total in operation. Germany has set its sights—not only on new pipeline construction, which is costly and time-consuming and occasionally controversial with locals—but also on the country’s large existing network of long-distance natural gas pipelines.

Internationally, too, the opportunity is clear. For green hydrogen to play a major role in global decarbonization efforts, an infrastructure for the efficient transportation of hydrogen must be established—and quickly. And while there are now just around 5,000 kilometers of active hydrogen pipelines worldwide, the length of pipeline already delivering oil and gas is over one million kilometers. If the technology works, and if the price is right, this development may represent a major boon for managing the hydrogen transportation challenge worldwide.

The unique properties of hydrogen pose unique technical challenges

Turning petrochemical pipelines into hydrogen pipelines is not just as simple as changing what flows through them. Natural gas networks often need to undergo modifications like the replacement of components such as valves, compressors, sealing membranes, and pressure regulators so as to be able to handle hydrogen’s particular flow properties. Pipelines must be monitored and tested for cracks; some older pipelines need to be replaced altogether.

Here, the particular characteristics of hydrogen pose technical challenges. One such characteristic is hydrogen’s tendency to cause embrittlement in steel. This process can occur when, for instance, H2 molecules dissociate at the steel’s surface into two hydrogen atoms, which migrate deep into the material then recombine in micro voids to form H2 gas, thus building up pressure inside the steel that causes damage. Different kinds of steel are affected differently, so not all pipelines that can reliably transport natural gas are also safe for hydrogen. Novel embrittlement-resistant grades of steel are sometimes recommended for new hydrogen pipelines and pipeline components, as are fiber-reinforced polymers.

Hydrogen is also flammable and prone to escaping. Leakage risks are therefore an important consideration, particularly at the valves and compressor stations where different pipeline components come together. Some valves designed for natural gas may not be able to seal off pipeline sections to hydrogen flow in a case of emergency, and would thus need replacing.

Since hydrogen has an energy density far lower than that of natural gas, even when compressed, it can necessitate larger pipeline diameters and compressors that can handle higher flow rates by increasing rotational speed. Safety and operations procedures would also need to be adjusted as a consequence.

How are natural gas pipelines being repurposed for hydrogen transportation?

Despite these challenges, the potential savings are considerable. Estimates diverge: a 2020 European Hydrogen Backbone study stated that the capital cost per kilometer of repurposed hydrogen pipelines could be around a third that of building new ones, while McKinsey and the Hydrogen Council have claimed costs of $0.6 to $1.2 million per kilometer for repurposing as opposed to $2.2 to $4.5 million for new pipelines. Altogether it seems likely that repurposing can offer serious advantages in terms of time and cost savings.

Technical solutions to the challenges of repurposing are already being researched, assessed, and in a few early cases implemented. The ideal approach depends partly on the pipeline section in question, with some solutions being more time- and cost-intensive than others. In some instances, only minor interventions—the replacement of valves and meters as noted above—may be required.

One straightforward option is just to implement more monitoring and maintenance for detecting leaks, damage, and any other potential hazards, while reducing the pipeline’s expected lifetime to account for the gradual onset of hydrogen embrittlement. In other cases, it may prove necessary to dig up certain stretches of pipeline and replace them using more suitable materials. Using the emerging pipe-in-pipe approach, smaller pipes—designed to withstand the transportation of high-pressure hydrogen—can be installed inside the outer pipeline. Because the inner pipe would not need to provide as much structural support, it would also be cheaper to produce.

Another potential solution involves coating the pipeline’s inner wall with an additional safety layer designed to resist hydrogen-induced degradation, although such coatings have so far been deployed before installation rather than as a fix on existing pipelines. The admixing of other gases into the stream can inhibit the impact of hydrogen embrittlement, even in very small quantities, adding a possible non-excavation option to the existing repertoire of techniques.

The second-hand hydrogen pipeline network is expanding

In Europe, particularly, the move to repurpose natural gas pipelines for hydrogen is now picking up steam. The European Hydrogen Backbone (EHB)—an initiative to develop a continent-wide hydrogen infrastructure guaranteeing secure supply and demand—projected in a 2023 report that its network could come to include some 33,000 kilometers by 2030 and 58,000 kilometers by 2040, with the majority at each stage contributed by natural gas pipeline repurposing.

Big-picture issues still remain, however. Hydrogen’s lower volumetric energy density means repurposed pipelines may end up delivering too little energy; the power requirements of compressor stations previously fueled with natural gas may pose challenges for grid operators. Regulatory frameworks and international standards specific to hydrogen transportation may be required.

Several operators are choosing instead to blend hydrogen into the natural gas—typically up to 10 or 20% by volume. Whether this offers a long-term boon to decarbonization is debatable. Similarly, so long as the hydrogen traveling through repurposed pipelines is derived from petrochemicals—like the hydrogen now passing by Baruth/Mark—then the mooted environmental benefits remain unproven. Some have warned that planning on repurposed gas pipelines runs the risk of fossil fuel lock-in and asset stranding, with potentially regressive effects for decarbonization.

GASCADE, the company repurposing the OPAL pipeline, is optimistic. They argue green hydrogen will be available from electrolysis plants in northern Germany and new local projects; there may also be imports from Baltic countries. Late last year, GASCADE announced its stretch around Baruth/Mark as the first step in Germany’s hydrogen backbone—and the country’s longest hydrogen pipeline yet. “This is our first time doing it,” Carina Gewehr, a manager, told the German press. “What we’re doing here is more or less pioneering work.”

Resources:

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Global Hydrogen Review 2021
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