"Critically, natural hydrogen may be not only clean, but also renewable. It takes millions of years for buried and compressed organic deposits to turn into oil

"Critically, natural hydrogen may be not only clean, but also renewable. It takes millions of years for buried and compressed organic deposits to turn into oil and gas. By contrast, natural hydrogen is always being made afresh, when underground water reacts with iron minerals at elevated temperatures and pressures. In the decade since boreholes began to tap hydrogen in Mali, flows have not diminished, says Prinzhofer, who has consulted on the project. “Hydrogen appears, almost everywhere, as a renewable source of energy, not a fossil one,” he says. "