Trillions of tons of underground hydrogen could power Earth for over 1,000 years: Study

A recent study suggests that trillions of tons of hydrogen gas may be buried beneath the Earth's surface, offering a vast and untapped energy resource that could significantly reduce reliance on fossil fuels.

Conducted by Geoffrey Ellis, a petroleum geochemist at the US Geological Survey (USGS), the research estimates Earth could contain around 6.2 trillion tons (5.6 trillion metric tons) of hydrogen within rocks and underground reservoirs, reports Yahoo News. 

This "geologic hydrogen" is formed through natural geochemical processes and has been discovered in limited locations so far, including Albania and Mali.

Reserves could be global but hard to access

The study, published in Science Advances, suggests these hydrogen reserves may extend globally. However, a significant portion lies too deep underground or far offshore to be easily accessed. Additionally, some reservoirs might be too small to make economic extraction feasible.

Despite these challenges, Ellis believes there is still immense potential. "Even with limitations, the results indicate there's more than enough hydrogen to go around," he told Live Science.

A low-carbon energy alternative

Geologic hydrogen is being considered as a low-carbon primary energy resource. The study predicts a resource range between 103 and 1010 million metric tons (Mt), with the most probable value being around 5.6 × 106 Mt. If just two percent of this hydrogen (about 1 × 105 Mt) were extracted, it could meet the projected global hydrogen demand to achieve net-zero carbon emissions for nearly 200 years.

To put this into perspective, this hydrogen holds more energy (~1.4 × 1016 MJ) than the world's proven natural gas reserves (~8.4 × 1015 MJ), highlighting its potential as a sustainable energy solution.

Challenges for large-scale extraction

Researchers developed a mass balance model to estimate the global size of these hydrogen reserves by combining geological data with an understanding of hydrogen formation and behavior. 

While the results are promising, experts caution that large-scale extraction poses significant challenges.

Prof Bill McGuire, an Earth scientist at University College London (UCL), expressed concerns, telling BBC Science Focus, "To extract hydrogen on a scale needed to make a meaningful impact on emissions and address the climate emergency would require an enormous global effort. Unfortunately, this is an initiative for which we simply don't have time."