Jacobson and his colleagues started by taking a close look at the current energy demands of each state, and how those demands would change under business-as-usual conditions by the year 2050. To create a full picture of energy use in each state, they examined energy usage in four sectors: residential, commercial, industrial and transportation.
For each sector, they then analyzed the current amount and source of the fuel consumed – coal, oil, gas, nuclear, renewables – and calculated the fuel demands if all fuel usage were replaced with electricity. This is a significantly challenging step – it assumes that all the cars on the road become electric, and that homes and industry convert to fully electrified heating and cooling systems. But Jacobson said that their calculations were based on integrating existing technology, and the energy savings would be significant."
-- Mark Z. Jacobson and colleagues, Stanford News