Hybrids. Those will be the stop gap between the next big energy source. Not just gas-electric hybrids, but diesel-biodiesel, gas/propane-ethanol, electric-biodiesel, gasification, electric-hydrogen, etc and etc.

Ethanol is very economically viable so long as you dont use corn. Corn doesnt have nearly enough sugar, so sugar beets and sugar cane would work so much better instead. That and you need to capture every last byproduct that isnt lost to thermodynamics.

Far as non-hydrocarbon power goes I put my vote for electric. Unfortunately the fearmongering about anything with the words "nuclear" or "atomic" in them basically kills that, because that just leaves us with hydrocarbons are super high output sources.

Hydro, geo, wave, solar, wind, and any other non-poluting environmental based power source arent really good enough. They're high loss systems, especially solar, and enviro-nuts kinda kill anything good.