Thiruneer Malai town in India uses methane gas which is produced by human waste to run a generator. The waste from an area housing complex is collected in a sump, where the methane gas is created.
The gas created is then used to operate a generator. The biogas is capable of producing 3,000 watts of electricity daily, which is more than enough to keep the town going all through the night.
You can check out the working of the plant on Natgeo: