We could be generating huge amounts of power from sewage. The process is pretty simple - just ferment sewage to produce a fuel called biogas. Biogas is almost entirely methane, and so is natural gas, so the two are essential interchangeable. The potential to produce biogas is almost entirely overlooked by most countries - except Sweden.
After the logging days and before outsourcing and current fuel costs, several cities in the state of Michigan enjoyed a prosperous hay-day of industrial ingenuity.