What I would like to see more of is garbage landfill methane. Collect and scrub the gas, run it into a portable gas turbine genset. Also a good way to deal with the real stinky landfills.
They do that at South Coast Botanic Gardens in Palos Verdes, CA- it's an old landfill, and there is a power plant running of the collected methane. I don't know how much power they get, though.
Each sewage plant could be a methane factory, too (though have you smelled the difference between aerobic and anaerobic fermentation?)