Experts are divided over how useful it could be.
The amount of energy we consume and its sources have long been at the heart of the climate crisis. For this reason, some strategies have shifted toward harnessing newer, cleaner fuels. A recent discovery of a vast underground reserve of hydrogen energy could offer a solution – but how much of an impact could it really have?
Geologic hydrogen forms through natural geochemical processes within the Earth and has so far been identified in only a few locations, such as Albania and Mali. A study published in Science Advances estimates that these reserves could exist worldwide.
According to the researchers, extracting just 2% of this geologic hydrogen could yield 1.4 × 10¹⁶ joules of energy. Impressive? Actually, this is only enough to power the world’s energy needs for about 35 minutes.
However, this is still double the energy found in all Earth’s natural gas reserves. Researchers argue that geologic hydrogen could play a role in helping policymakers achieve net-zero carbon goals. Currently, hydrogen is mainly produced from fossil fuels or through electrolysis, a process that requires significant water and often comes with a high carbon footprint.
In contrast, extracting geologic hydrogen is a relatively low-carbon process. However, Mali is the only country that is actively doing so.
In their study, scientists from the US Geological Survey developed a model to estimate the global size of hydrogen reservoirs, combining geological data with existing knowledge of hydrogen’s behavior.
Their model indicates there could be as much as 5.6 × 10⁶ metric tonnes of hydrogen beneath the Earth’s surface—equivalent in weight to 3.7 million cars or 1.56 billion flamingos.

The model inputs include annual generation of natural hydrogen, fraction of hydrogen detained in traps, residence time in reservoirs, proportion of biotic and abiotic loss, and the rate of anthropogenic production. The calculated outputs of the model are the amount of hydrogen stored in reservoirs at a given time and the flux to the atmosphere.
Despite this, experts remain divided over whether investing in extraction is worthwhile. “To suck up hydrogen at a scale required to make a contribution to bringing down emissions and tackling the climate emergency would require an enormous global initiative, for which we simply don’t have time,” said Prof Bill McGuire, Earth scientist at University College London (UCL).
“It would also need a massive amount of supporting infrastructure in terms of rigs, access roads, storage, transport, and more. Furthermore, it seems to me that we might now know how much hydrogen there is, but that is not the same as knowing where it is.
“There is more than enough free energy available from wind and the Sun alone, and the technologies are straightforward, well-tested, and well-established, so I really don’t see the need for exploiting what is, ultimately, another finite resource.”
Prof Bill McGuire is a volcanologist, climate scientist, writer and broadcaster. He is currently Professor of Geophysical & Climate Hazards at UCL, and has written several books including Natural Hazards and Environmental Change; A Guide to the End of the World – Everything You Never Wanted to Know; Surviving Armageddon – Solutions for a Threatened Planet; and his latest best-selling book, Hothouse Earth: an Inhabitant’s Guide.