Just saw an article on bio-mass plants on the History Channel last Friday. What they do is capture the methane from decaying garbage and use it for fuel for the plant. There's a huge plastic "tarp" as a liner in a pit, the garbage in thrown in and another plastic "tarp" on the top. The methane is scavenged from the top liner and sent to a storage tank for the generator fuel. One could do that in their own back yard with just bio-waste such as grass clippings, etc.
In all honesty, I used to drive by a waste dump near Rosemount, MN. back in 86-90 time frame. They had a stack coming from the ground over the garbage heap, burning off the methane. I used to think to myself, why not capture that methane and use it instead of simply burning it off?? Someone must have a like idea and actually put it to practical use.