Not quite where I was going. Yes electric motors, sure, but where are they going to draw their power from? I know batteries! But where will the batteries draw their power?
Consider that 1 gallon of gasoline has approximately 115000 BTU of energy. We have absolutely Nothing that can even come close in energy! Solar energy via panels doesn't even come close, plus there is a time factor involved (think time derivative). So how are we going to power those fancy nasa electronic motors?
This I feel is the real problem! Add to that the overall efficiency of a system. What we desperately need is an alternative fuel source that can at least come close to fossil fuels in both BTU output, and time derivative. The other part is improving the efficiency of engines that utilize this fuel.
Yes if we could find an engine that operates on technology other than thermal energy, that would be good. But short of a nuclear reactor, we do not have this technology (or at least a mobile version).
All is not lost, I think there is real potential in bioengineering of fuels. My vote also goes to oilshale. Neither oil nor shale, but has enormous potential!
My point is this. Before AI comes of age, fossil fuel dependence will be a show stopper. So in the meantime that is a wonderful area to invst in.
My .02
