Two researchers at the US Geological Survey (USGS) have calculated that the potential in-place geologic hydrogen resource in the earth ranges from 10³ to 10¹⁰ million metric tons (Mt), with the most probable value of ~5.6 × 10⁶ Mt (5.6 trillion metric tons). Their findings are published in an open access paper in the journal Science Advances.

Although most of this hydrogen is likely to be impractical to recover, a small fraction (e.g., 1 × 10⁵ Mt) would supply the projected hydrogen needed to reach net-zero carbon emissions for ~200 years. This amount of hydrogen contains more energy (~1.4 × 10¹⁶ MJ) than all proven natural gas reserves on Earth (~8.4 × 10¹⁵ MJ). Study results demonstrate that further research into understanding the potential for geologic hydrogen resources is merited.

—Ellis and Gelman

Conceptual model of geologic hydrogen resources. 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. Ellis and Gelman

The advance of hydrogen as a major element of the energy transition has been hampered by sourcing problems. Although electrolysis of water using renewable electricity and production from fossil fuels coupled with carbon capture, utilization, and storage show promise, realization of required production levels will require development of infrastructure at an unprecedented rate), as well as substantial contributions from technologies that are not commercially viable today, the researchers note.

A discovery of a substantial accumulation of natural hydrogen in Mali, Africa challenged the long-held view that such fields do not exist.

A recent compilation of published studies on the global generation of natural hydrogen in all geologic settings estimates the amount to be 15 to 31 million metric tons (Mt or 10⁹ g) per year. Because the global demand for hydrogen is projected to reach ~530 Mt year⁻¹ by the year 2050, production of all the annually generated hydrogen in the Earth’s subsurface would likely represent a small fraction of the needed supply. However, the resource potential for geologic hydrogen is not only dependent on the generation rate but also on the propensity for hydrogen to become trapped in the subsurface and for accumulations to be preserved.

—Ellis and Gelman

Resources

• Geoffrey S. Ellis, Sarah E. Gelman, Model predictions of global geologic hydrogen resources. Sci. Adv. 10, eado0955 (2024) doi: 10.1126/sciadv.ado0955