France hits hydrogen jackpot: largest reserve valued $92B found

For example, the Haber-Bosch process requires hydrogen and nitrogen to produce ammonia, which is used as fertilizer. Traditionally the hydrogen is obtained from methane, but that emits a massive amount of CO2 - about 1% to 3% of all worldwide CO2 emissions. Feeding the process directly with hydrogen would be a gamechanger.

>Most hydrogen is likely inaccessible, but a few percent recovery would still supply all projected demand — 500mn tonnes a year — for hundreds of years

Most of it comes from a reaction between water and 'ultrabasic rocks' according to Wikipedia. It hasn't been searched for much as it occurs in different geology to natural gas and there hasn't been much demand till recently.