IMO If they are going to be cost effective they will use methanol....On my computer that crashed there was a long list of all the bi-produces that were now considered waste that could be turned into methanol......We have one of the larger "dumps" in the midwest a few miles from here (Click on Hoosiermama) Would love to see 90% of it turned into energy....Probably not in my lifetime, but maybe my grandchildrens.
Jim, Does it count that I still have my slide rule?
Natural gas is the primary source of hydrogen now. Methanol might do, either directly or as converted to hydrogen. There are cars already that can run on alcohol or gasoline at the flip of a switch. That isn't hydrogen, but alcohol could run the fleet, and does, if I hear right, in Brazil.