There's also hydrogen fuel cells to consider, which at 142 MJ / kg and 50% efficiency looks like this: 1 kg * 142 MJ / kg * 50% = 71 MJ mechanical The dominan

There's also hydrogen fuel cells to consider, which at 142 MJ / kg and 50% efficiency looks like this: 1 kg * 142 MJ / kg * 50% = 71 MJ mechanical The dominant solution above all else.