Comment by peterfirefly

I didn't expect it to complete replace all fossil fuel -- just almost all the coal + a large share of the oil. Cars would still have used petrol. Heating could have become largely electric. If they really wanted, they could have used synthetic petrol -- but that is rather inefficient.

The US produced (and produces) lots of oil. It would probably have been enough (or close enough) to make the US entirely independent of OPEC oil.

The two proposed solutions were: military (the road taken), very expensive research (not really taken). I added a third one (nuclear) because it was cheaper and it wouldn't have needed much research. It was a known solution that would have gotten the US most (likely all) of the way towards energy independence and it would have reduced CO2 emissions a lot.