If I ran the numbers right, only about 15% of the energy consumed in the US is produced in the form of electricity (4,127 billion kWh vs 100.2 quadrillion Btu consumed, 1kWh ~ 3400 Btu).

So going 100% renewable or nuclear for electricity production wouldnt' even make more than 15% difference.

I wonder what causes all that additional energy consumption from fossil fuel sources then? I always blindly assumed ~50% of our energy consumption is in the form of electricity. Cars and transportation, heating are obvious but I wouldn't expect that to account for such a large share. Does industry use so much fossil fuel for energy?