And in recent years, hydrogen has become a major player in this energy mix of the future.
Demand for the gas inched close to 100 million tonnes in 2024, according to the International Energy Agency (IEA), driven by increased usage within industry. Low-emissions hydrogen, which is not produced by fossil fuel use, makes up less than 1% of that global total, but is rising prodigiously.
The problem is that hydrogen storage is not rising at the same rate: the IEA forecasts that only 5% of all the world’s announced hydrogen storage projects have reached a final investment decision or are under construction. This is partly down to the difficulty of storing the resource. That’s where engineers come in, to enable net-zero targets to be reached while making sure precious resources are not wasted.
“With the government’s ambition for net zero, the options for achieving that are not hugely numerous,” admits Edward Hough, research lead in underground energy storage at the British Geological Survey. “One of the main ways it’s thought we can achieve net zero is by increasing the blend of the energy mix. Introducing hydrogen into that is seen as one of the ways we can achieve low-carbon energy.”
The issue is that hydrogen’s chemistry famously makes it harder to handle than natural gas, posing tough infrastructure and engineering questions. There are also challenges when it comes to holding the gas in above-ground tanks, which are limited in their size, expensive and can often be seen as a blight on the horizon – pushing engineers towards more nature-based, underground options such as salt caverns and depleted gas fields. This is part of the business plan of UK Energy Storage, an energy developer aiming to deliver its first UK hydrogen storage site by 2030 by developing projects in South Dorset and East Yorkshire.
The UK is well-positioned to take advantage of a nascent hydrogen market, reckons trade body Hydrogen UK. “With most of Europe having highly limited access to underground salt layers, the UK’s favourable geology, technology and expertise have the potential to create considerable export opportunities to UK businesses,” it wrote in a 2022 report.
Sticking hydrogen underground may sound simple, but this is where the element’s temperamental nature comes into play. “Hydrogen is quite a reactive element,” Hough says, and that matters because “some of the natural minerals in rocks can react with it” – potentially changing the quality of what comes back out. There is also, he adds, “a question of whether or not microbes might consume hydrogen”, which could reduce the amount stored and, in some cases, affect reservoir integrity, although this is a bigger worry for porous rock storage than salt caverns, which are “quite a hostile environment for microbes to live in”.
Nevertheless, salt caverns have one big advantage when it comes to storing hydrogen: engineers are not starting from scratch. Beyond the space carved deep underground over millennia, there’s the technical know-how, too. “There has been hydrogen storage in caverns since the 1980s in the UK,” Hough says. “It’s an established technology.” He points to operating sites overseas too, including massive active salt cavern storage sites across the Gulf Coast and Permian Basin in Texas, which the UK can learn from as it scales up.
So why aren’t we already going full tilt if Texas is? The blockers are “probably a bit broader than engineering,” says Hough. Comparatively low demand for hydrogen leaves developers in a bind. “If you’re an operator, you’d have to take on quite a big financial risk that you would have the market there to necessitate the development of a large-scale storage facility,” he explains.
For a sufficiently buoyant hydrogen market to appear, big industrial users would have to be willing to shift away from natural gas – and that “would be a very expensive process for them,” says Hough. The result is a chicken-and-egg problem: “Before we can think about developing hydrogen storage facilities, there has to be the economic and business model in place that would support that.” It’s particularly problematic because hydrogen can react with standard steel used in compressors or in borehole casings, meaning operators sometimes need to swap in hydrogen-resistant steels – which cost more money as specialist products.
But where there are opportunities, projects are cropping up. These exist across the UK in varying stages of development, including the South Dorset Storage site overseen by UK Energy Storage, the same firm’s caverns in Cheshire and East Yorkshire, and others in Teesside. The geology in all the sites is promising for hydrogen storage, Hough says, but viability still comes down to geography as much as the quality of rock. “Have they got local areas supplying hydrogen, and have they got areas where they can actually sell the product?” he asks.
The solution to that is a blend of more innovative technology and better governance. “Having appropriate policy drivers in place” and “the right regulation regime” can build confidence in hydrogen, Hough reckons. Hydrogen may not end up heating most UK homes, but as part of “a portfolio of technologies”, he argues, it could still be “really important” for industry and the power system of the future.
Find out more
Engineering a Hydrogen Economy 2026 will take place from 29 to 30 April at Millennium Point, Birmingham. Now in its sixth year, this annual conference tackles the critical challenges of scaling up a hydrogen economy: driving down costs, developing infrastructure, overcoming storage limitations, the regulatory framework, investment and the skills gap to bridge the commercialisation gap. Find out more and book at imeche.org/events
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.