Could natural hydrogen from underground help the UK get to net zero?

In recent years, the discovery of small amounts of hydrogen gas underground has spurred a worldwide search for what could prove to be a significant new source of zero-carbon fuel, but so far, prospectors have largely skipped the UK.

According to a briefing on natural hydrogen produced by the Royal Society, that isn’t due to its geology. “There are rocks that certainly would fit within having the potential to produce hydrogen, but the investigations haven’t been done,” says Barbara Sherwood Lollar at the University of Toronto in Canada, who led work on the report.

It also isn’t down to lack of interest in the gas. The UK’s latest hydrogen strategy says that when produced via low-carbon methods, it “has a critical role in helping to achieve our Clean Energy Superpower Mission”, including as a source of power for heavy industry and transportation and in long-duration energy storage. Natural hydrogen, however, isn’t mentioned as a potential source.

Novelty is one reason for this, says Philip Ball at Keele University, UK, who contributed to the report and is an investor in natural hydrogen companies. “Nobody is paying attention, basically. No one is regulating this new subject. No one understands it.”

That could be starting to change. Ball says several companies have purchased rights to explore for hydrogen in parts of the UK, for instance in Devon in the south-west, while relevant research is going on at several universities. The British Geological Survey is also working on a more detailed study of the potential for natural hydrogen in the UK. The country’s rich history of geological study means there is plenty of data to draw on.

And there is reason to think there might be something to find in it. According to the Royal Society report, the UK has ample amounts of the rocks known to generate natural hydrogen, for example iron-rich ultramafic rocks that produce the gas when they react with water. These occur in regions such as the Lizard peninsula in Cornwall and the Shetland Islands in Scotland. Geological formations in other areas such as the North Pennines may also produce hydrogen as a result of natural radioactivity splitting water molecules.

“It’s most definitely going to be in the UK,” says Ball. “Whether it’s in economic quantities is the question.”

If there is hydrogen to be found beneath the UK, no one should expect “some bonanza of an endlessly renewable commodity”, says Sherwood Lollar. She says one broader purpose of the report was to offer a “course correction” for some of the more dubious claims that have been made about natural hydrogen, such as the idea that large amounts of the gas are rising from deep in Earth’s mantle or even core.

That said, more conservative estimates of how much hydrogen may be generated in the crust are still significant: the report estimates that around 1 million tonnes of the gas seep out of the crust each year globally, which over time could produce some large accumulations. “Even if we can capture a small proportion of this, it could still be an important contributor to the hydrogen economy,” says Sherwood Lollar.