The San Jose/Santa Clara Water Pollution Control Plant currently creates two-thirds of its energy from methane from digesters and landfills. They just signed an agreement with FuelCell Energy for a 1.4 MW fuel cell system powered by biogas from their own treatment process.
Fuel cells operate 24/7 with virtually no emissions. Imagine the cost reductions and cleaner air that would result if all wastewater plants did the same. The more that power can be produced locally, the better.