a) Global output today b) Maximum possible global output if everyone gets as much electricity as, say, me c) Minimum global output necessary to provide, say, lights in the evening, cooking, heating, refrigeration and maybe a computer (or other--one other, I mean--electrical device) running 24 hours a day per person. I know it's not a good list, but I think some minimum figure is needed so that with d) Total global output possible from all renewables using current technology (incl. wave which I think is about to come online big time)
Then, following Jerome's list:
c) gives us 1) d) gives us 2)
and if nuclear fills the remaining gap, then that will be the number of nuclear power stations needed, which I still think would become zero as renewables have all kinds of knock on effects...all the greater to the extent that they are widely distributed--the local wind turbine(s) etc...--because they influence c) and also because new tech always creates even more new tech (cf. computers 1948-the present.)
My tuppenceworth. Don't fight forces, use them R. Buckminster Fuller.
That division might also partially break down into DeAnander's "left/right" and "technocrat/green"...it mixes the "I deserve as much as I can get--and can pay for"; "Don't make me eat cold porridge, this tech. is great, let's use it!"; "We're all doomed if we keep consuming this much!"; "We'd be happier if we switched off, wandered out, and got back into our bodies"...and all those many points between, beyond, and elsewhere. Don't fight forces, use them R. Buckminster Fuller.