Yesterday, I saw a demo of the Homebiogas bioreactor: it's essentially an artificial stomach that uses colonies of microbes to digest your home food waste (it can do poop, too, but people tend to be squeamish about this), providing enough clean-burning biogas to cook your next meal, heat your house, or run a generator — what's left behind is excellent fertilizer.
Biogas is a pretty well-established technology (Marco Polo came back from China with stories of pipes coming out of subterranean middens that supplied clean-burning gas), but it has fallen out of favor in the past century or so. Bioreactors are small, cheap, odorless, and very simple — the people behind Homebiogas also build open source bioreactors all over the world, in refugee camps, prisons, cold climates, hot climates, cities and the countryside.
Home bioreactors are small enough for apartment living, and provide a bridge for people trying to live on renewables — powering generators or supplying cooking gas when the sun is down or the wind stops blowing.
My family and I just bought a house in Southern California and are planning a renewables renovation in the next couple years (depending on book advances!), and in addition to a solar roof, I'm definitely going to look at setting up our house to turn our food-waste into energy.