I ran into the following quote today in a power textbook from 1948:

The sources of energy for large-scale generation of electricity are: 
1. Steam, from (a) coal, (b) oil, or (c) natural gas 
2. Water (hydro-electric) 
3. Diesel power from oil 
Other possible sources of energy are direct solar heat, windpower, tidal power, shale oil, and atomic energy, but none of these as yet has gone beyond the pilot-plant stage, for the reason that coal and petroleum are still abundantly available. But as fossil fuels become scarcer and more expensive, there is every reason to believe that. all of these, as well as petroleum manufactured from vegetable matter, 
may become useful and economical supplementary sources of energy. 
--C.A. Powell

It is remarkable how slow the utility industry changes. We have nuclear, and oil is too expensive to burn for electricity anymore but other than that we are doing things pretty much like we were in World War Two