Extracting even a small proportion of the natural hydrogen currently underground could be enough to supply the world’s needs for 200 years, according to new research.
Hydrogen is expected to make up as much as 30% of the future energy supply in some sectors in future, particularly those which are hard to electrify like heavy industry and chemicals manufacturing. At the moment, the expectation is that much of that hydrogen will be generated from the electrolysis of water using renewable electricity (often known as green hydrogen) or from fossil fuel sources with the addition of carbon capture, utilisation, and storage (blue hydrogen).
Either way, creating enough hydrogen is going to be a big challenge, and requires development of infrastructure at an “unprecedented rate as well as substantial contributions from technologies that are not commercially viable today,” according to the paper from researchers at the U.S. Geological Survey.
Geological or natural hydrogen – also known gold hydrogen - could be an extremely useful alternative – but until recently it has been unclear just how much of it was available or accessible.
But the researchers from the US Geological Survey have published a paper in Science Advances which suggests that, even if only a small amount of the hydrogen trapped underground could be captured, it would be enough to meet the world’s needs for around 200 years. The researchers calculate there is somewhere around 5.6 trillion tons of hydrogen hidden under the earth, with another 15 to 31 million metric tons created each year.
While that sounds like – and is – a lot, the researchers said that, given what is known about the distribution of petroleum and other fluids like helium and CO2 in the subsurface, much of this hydrogen is likely to be “too deep, too far offshore, or too small” to be economically recovered. But because there is so much, even recovering a small amount of the easiest-to-find hydrogen could make a significant difference.
Global demand for hydrogen is expected to reach 500 Mt per year by 2050, and the paper notes: “recovery of just 2% of the estimated most probable in-place resource would meet the entire projected global hydrogen demand for ~200 years.” The energy content of this potentially recoverable amount of hydrogen is roughly twice the amount of energy in all the proven natural gas reserves on Earth, they point out.
However, even a ready supply of low-carbon hydrogen will only make a meaningful contribution toward meeting net-zero carbon emission goals if it can be developed quickly. The researchers point to the experience of US shale gas development to suggest that geologic hydrogen could begin to make a “substantial” contribution to the global energy supply within decades, potentially reducing the need for the carbon capture, utilisation, and storage requirements of other types of hydrogen.
“The study results indicate that a substantial hydrogen resource could exist in the subsurface of Earth, the magnitude of which, if proven, could substantially contribute to the decarbonization of energy resources but is not likely to be renewable. These findings indicate that further research in this field is warranted,” the paper said.
Already start-ups and other companies are looking at the options for finding and accessing geological hydrogen. Last year the US government awarded $20m in grants to projects aimed at stimulating hydrogen production from mineral deposits found in the subsurface, and to projects focusing on technologies for the extraction of geologic hydrogen.
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