Lots of good information here, but let's not get overly enthusiastic - I've been reading about hydrogen power as the next big thing since the twentieth century.

The big issue is energy density. Burning H releases a lot of energy per gram, but at standard pressure and temperature its energy density, that is, the energy per unit volume, is low.

You can compress hydrogen considerably but then each vehicle becomes a rolling bomb. I don't even think this has been seriously proposed, let alone attempted.

Clearly some sort of fuel cell is needed, which will reduce the energy density but make it much safer to use. We got to that point in the 1970s, and then researchers have slowly been figuring out how to make such a fuel cell that you can use for tens of thousands of power cycles and that hopefully can be reconditioned after that.

If you made me world dictator, I'd put rising taxes on all fossil fuels that were painful at first and rose in a decade to unbearable, and use all that money to research fusion power, batteries and and then maybe fuel cells as well as other renewables.

If we aren't going to actually decimate our ecosystem with +3º and up, at some point we need to go carbon negative and start "pumping" the CO2 out of the air.

That's going to require simply huge amounts of energy to accomplish, and fusion is the only power source huge enough.

IMHO.

Thanks for a thought-provoking article!