Opinion | A Gold Mine of Clean Energy May Be Hiding Under Our Feet - The New York Times

The big break came in 2012, as the article in Science this month recounts. A businessman in Mali named Aliou Diallo hired Chapman Petroleum Engineering Ltd., a Canadian consulting firm, to analyze the mysterious gas coming from a borehole on his property. It turned out to be 98 percent hydrogen. The gas was used to fuel an engine that ran a generator. "That gave Bourakébougou" — the town nearest the well — "its first electrical benefits: freezers to make ice, lights for evening prayers at the mosque, and a flat-screen TV so the village chief could watch soccer games," the Science article said. What's most exciting is that the hydrogen has continued to flow ever since. 

Geologists now believe that hydrogen is being constantly produced from a reaction between water and iron-rich rocks. It's essentially rusting: The rocks capture the oxygen and release hydrogen. Some hydrogen may also be bubbling up from deeper in Earth or be formed by radioactivity, which splits water molecules. Hydrogen has been found on all the continents except Antarctica, which hasn't been checked yet. In the United States, the two most promising places are along the East Coast (onshore and offshore) and along an ancient ridge system extending from Kansas to the Great Lakes, Zgonnik said...

https://www.nytimes.com/2023/02/27/opinion/hydrogen-natural-climate-change.html