High-profile successes in the UK include adoption of hydrogen technology in major construction projects such as the Lower Thames Crossing, approvals for green hydrogen production facilities and development work on hydrogen-centric industrial clusters. Some ambitious targets have been missed, however, and the long-term future for the fuel and energy vector remains unclear.
With challenges to solve and more progress to come, IMechE’s Engineering a Hydrogen Economy returned to Birmingham last week (29-30 April). The conference remained as – if not more – relevant than ever in its sixth year, said event chair Dr Maria Felice, industrial liaison manager for hydrogen at the High Value Manufacturing Catapult.
Described by the chair as prioritising “engineering and facts over hype and misinformed opinions”, the event covered a wide range of themes and projects. Here are three key questions raised by speakers – and some answers.
When will the new hydrogen strategy be available?
Barriers to the hydrogen economy in the UK were unavoidable at Millennium Point, projected as they were on the conference venue’s massive Imax screen. From a lack of distribution networks to the cost gap between fossil fuels and hydrogen, the hurdles were presented as part of an interactive poll during a morning session on the first day.
Asked to choose, attendees – including researchers, mechanical and chemical engineers and representatives of trade organisations – were clear: the absence of a transparent, long-term hydrogen strategy is the most pressing issue, selected by 38% of respondents.
Delays to the strategy – which had been due for publication in autumn 2025 – are affecting sector confidence, said Dr Emma Guthrie, CEO of the Hydrogen Energy Association trade organisation. “If we don’t see this movement, there is a risk of the UK falling behind global peers,” she said. Despite some “very large ambitions” from the government, the delays mean the UK has slipped below Germany as the most attractive place to invest in hydrogen, she added.
The delayed strategy “will significantly impact the demand that is coming from the industry,” said Dr Shahrouz Nayebossadri, principal R&D engineer for hydrogen systems at the Offshore Renewable Energy Catapult.
The UK’s “very favourable” current programme of Hydrogen Allocation Rounds is nonetheless recognised by other countries, Guthrie added, with attractive rates available for domestically produced low-carbon hydrogen.
Professional Engineering contacted the Department for Energy Security and Net Zero for an update on the strategy’s publication.
What will power the hydrogen economy?
While the roll-out of hydrogen infrastructure has faced delays, other pillars of the green energy system are already in place. In 2025, renewables generated a record 52.5% of the UK’s electricity, largely thanks to a productive year for wind and solar generation.
That electricity is already powering millions of homes and businesses – but when it comes to electrolytic production of ‘green’ hydrogen using water and renewable power, decarbonisation could cause some issues.
Chief among these is intermittency, highlighted by speakers throughout the event. A constant feature of renewable power due to fluctuating weather conditions, but at its worst during dunkelflaute – periods with little wind or sun – stop-start generation could be a significant drawback for hydrogen producers, as electrolysers operate most efficiently with steady, continuous power.
“This can significantly impact the lifetime of electrolysers,” Nayebossadri said. “This is something that we have to carefully think about, and see how we can actually improve the durability of the electrolysers in order to… reduce the overall cost of hydrogen production.”
Questions remain around the costs of electrolysis, agreed fellow panel member Dr Robert Sorrell, CEO of the government-backed Royce Hydrogen Accelerator. “There’s this big challenge around bringing down the costs of electrolysis and actually… recognising what a realistic cost of production is,” he said. “Some of the figures that are quoted are based on an old paradigm of comparing to oil and gas-type structures, where actually it’s not particularly appropriate.”
Along with durable electrolysers, new and more widespread energy storage options will be needed to maximise hydrogen production using renewable energy.
Are we ignoring a golden underground opportunity?
Whether it is green electrolysis, steam methane reforming or another process, the dominant production method for the future hydrogen economy remains up for debate. But there is another option, according to José Mária Santa Bárbara, director of the Aragón Hydrogen Foundation in Spain.
Found underground in Aragón, as well as at Mount Chimaera in Turkey, mines in Ukraine and other subterranean locations, is naturally produced – or ‘golden’ – hydrogen. Extraction projects are being developed in Spain, Australia and France, and one is already operating in Mali. “What was once considered waste is now the fuel of the future,” said Santa Bárbara.
Described by the speaker as a potentially cost-effective complement to green hydrogen, the gas is produced by several distinct processes: radiolysis, in which irradiated water splits; an exothermic reaction between water and underground rocks known as serpentinization; and magma degassing.
Exploration and extraction technology needs to be developed – but once it is, Santa Bárbara claimed, the process could have similar costs to oil and gas production. Trillions of tonnes of natural hydrogen could be available in the Earth’s crust, according to the US Geological Survey, with only a small fraction needed to reach net zero carbon emissions for the next 200 years.
“The key is that this is something that is being generated constantly,” Santa Bárbara said. “If we have the possibility to actually gather that and make it work, it will be like a constant flow of energy coming at very low cost.”
Extraction techniques could include accessing confined underground reservoirs, drilling into hydrogen-rich rock formations or injecting water into formations with high iron content, forcing hydrogen generation.
Doing so will not be easy, however, largely thanks to hydrogen’s high diffusivity, due to its small molecule size. This also causes embrittlement of metals, requiring new material solutions.
Another challenge, raised by a member of the audience, is that serpentinization also produces carbon dioxide. Santa Bárbara said the gas could also be extracted and sold – but ties with the greenhouse gas could be seen as a mark against golden hydrogen’s climate credentials.
The use and commercial viability of hydrogen-based combustion engines will be explored at IMechE’s Advancing Automotive Engineering event, taking place at the British Motor Museum in Warwick from 4-5 November. Find out more and book on the event page.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.