I've been fascinated by methane digesters for a very long time. There was even a point when I was, kind of, obsessed with them. In fact, I think in the kind of society in which we live, where we generate so much waste, that a methane digester is the BEST way to generate electricity. The fact is that using waste to make methane gas to boil water to run a turbine to make electricity is infinitely more efficient (methane is comparable to natural gas in the way that it can be used and burned) than any fossil fuels.
Methane is highly explosive and requires careful handling, and it smells horrible, but in a society with the millions of people we have who are generating so much waste, it just makes sense that we start closing that loop and start looking for ways to use those things that are, at the moment, just considered waste. In some cultures, there is no such thing as waste. Everything has a purpose. We'd really be doing ourselves a favor to adopt that attitude.
In New York City, a waste treatment facility is experimenting with providing electricity for homes using a methane digester. Area restaurants will be providing food scraps. It's a win/win for everyone. They're reducing the amount of food waste that ends up in landfills, reducing their dependence on unsustainable sources of electricity, and the end result of the process is, actually, compost, which could be used by urban gardeners to grow food ... that is served in the area restaurants ... that give their food wastes to the treatment facility ... that produces electricity ....
There are so very few examples of a truly closed-loop system in our society of consumerism and wanton waste. This one ... this one makes me smile.
**Edited to add: Little Homestead in Boise posted a comment about a Chinese family with a residential-sized methane digester, and in the years I've been looking at these, I've found a lot of examples of the same thing - here in the US. Several years ago, I actually found a company in India that was making residential-sized digesters (not sure what happened to them).
It is definitely time to start looking more seriously at this kind of thing for use in the developing world. I mean, just because we (think we) have access to unlimited cheap resources is no reason to use them with abandon. Even when my chickens are laying like crazy, I don't waste eggs. In fact, I freeze eggs to use later when the chickens aren't being so generous.