Hydrogen found in Earth's crust is 'limitless fuel supply'
https://www.telegraph.co.uk/news/science/science-news/3293426/Hydrogen-found-in-Earths-crust-is-limitless-fuel-supply.html
Well, there is a reason that that cubic meter of rock still has that hydrogen trapped in there: it IS trapped. Granite is not especially known for its permeability, and despite the fact that hydrogen is the escape artist of gases, even able to work its way out through the wall of steel cylinders used to store gases, it hasn't worked its way out through the granite.
It's one thing to frac shale or tight sandstone/silt/dolomite sequences, but granite?
When I was running mass spec on wells in Weld County Colorado (DJ Basin), the only time we got noteworthy Hydrogen returns was when there was a mechanical problem downhole, and metal-to-metal contact/friction generated heat sufficient to dissociate water downhole. It was a signal that something was very wrong with the tools downhole. Otherwise, we saw very little.
That isn't saying it isn't present elsewhere, just that it has not been common in areas where I have worked (ND, MT, SD, WY, UT, CO, NV, TX), with equipment that can detect it. Then, too, those areas were known for petroleum, and that would have absorbed most of any free hydrogen present.