underground but not a fossil
 

Wells! Wells are being bored all over. Natural Hydrogen seems to be a coming thing.
Before today I hadn't heard that there could be exploitable amounts of hydrogen underground. This week's issue of Science magazine (vol. 379 17 February 2023) has an article: "Hidden Hydrogen" which is a long story about all the people and places that are being examined for natural hydrogen. There is a village in Mali now powered by hydrogen gas from a 100 meter deep well (via a internal combustion engine driving a generator for electricity). There is an exploratory well near Geneva, Nebraska. One planned for the Pyrenees for next year. Lots of exploration in south Australia. The first scientific discussion of natural hydrogen is from Dmitri Mendeleev. In 1888 he reported hydrogen seeping in a coal mine in Ukraine.
Hydrogen seeps are believed to be the cause of geological depressions called "Fairy Circles" and there are fairy circles in North Carolina, Brazil, Russia, and Mali.

Using a simple way to estimate how much hydrogen there could be, based on a method developed by the oil industry, researchers at the USGS say the model comes up with a range centered on a trillion tons of H2.

It is believed that most of the hydrogen comes from serpentinization, which is an on-going process. It could be stimulated by pumping water into iron-rich rocks.

Hydrogen mine promoters are pushing "this is the next energy boom" bigger than oil or fracking or anything.
I think it might come together about the time Fusion power generators need more hydrogen. Some time between 20 years and never.
-mort

It will probably be about as big as geo thermal energy.
The oil companies make hydrogen at tremendous cost for hydrocracking, if they could drill a hole and get it out of the ground which is kind of their thing they would have by now.

Lizard-people!

hydrogen storage
 

In the not too distant past, hydrogen storage was an issue.
As the 'smallest' atom, hydrogen was capable of escaping through the walls of any vessel it was stored in.
There was a promising carbon nano-structure which was capable of 'holding' the gas, but to get it back out required heating the vessel, adding entropy to the 'system' and reducing its market viability.
I believe that California's 'Hydrogen Highway' ( Gov. Arnold Shwarzenegger ) relies on natural gas as the feed stock.
Rather than attempt to store significant amounts of gas onsite, SHELL and TrueZero equipment harvests the gas from a PP&G natural gas pipeline, then a high-pressure compressor forces it into the Toyota or Honda fuel cell at 700-bar, and $45-$50 a fill.
MOTOR TREND's Toyota Mirai has averaged 67.8-mpg over 13,822-miles.

There's nothing economical about hydrogen.

'economical'
 

The only argument I've heard in favor of hydrogen as a 'motor' fuel has to do with the inability to charge BEVs at apartments.
Apartment dwellers have the capability to drive an 'electric' car via hydrogen fuel cell cars, fueled by hydrogen.
The fossil fuel folks like it because they'll provide the natural gas, typically used today, to create the hydrogen.
TrueZero has tripled the number of stations in California.
Five years of hydrogen costs $ 15,000 right now ( Toyota Mirai XLE ), averaging 331-miles / tank.

Last time I checked hydrogen was $15 per kg at retail.
Toyota claims their hydrogen car goes 50 to 70 miles on 1kg.
Gouge your eyes out cost per mile is one of the many reasons I think hydrogen sucks.

'kilogram'
 

It would be helpful to people like me if a ' kilogram' of hydrogen was defined in terms of a gallon of gasoline-equivalency, as kilowatt-hours are done, so I could better wrap my head around it.

"A pint's a pound the World around" said someone.

Imperial to Metric left as an exercise. Better to compare BTUs.

'said someone'
 

'The closer you get to death, the less life you have, but you still have more!
(unknown)
' You better slice that pizza into four slices. I don't think I can eat six!'
Yogi Berra
' I may talk slow, but I am stupid.' Woody Harrelson, Cheers