How long before the Gulf oil spill is no longer a trending topic? A long time, unfortunately. Yet there are ways to create fuel that don't involve offshore drilling or deadly, expensive military campaigns. Flint is counting on sewage.

The Michigan city has partnered with Swedish Biogas to construct a plant in Flint that digests and converts sewage sludge into fuel. The timing is right. Sewage has been spilling into the Great Lakes for years, from old wastewater systems that can't handle flows during rain and storm events. And a new federal study says biogas from sludge is within pennies of becoming competitive with conventional diesel. 

So far, the Flint-Swedish Biogas project has attracted $7 million from the state, the federal government, the Swedish company and the Swedish government. A groundbreaking is due any day. More funding also may be on the way, says Flint Mayor Dayne Walling, who recently returned from a project-related trip to Sweden. He says Swedish Biogas may be investing additional money in the plant, to expand the operations in Flint before they even get started. 

In Linköping, where Swedish Biogas is located, a plant that opened in 1996 provides fuel for 70 buses and the world's first biogas-powered train. Expansions are planned there, too, to produce more biogas --- another word for methane produced by microorganisms. After the sewage sludge becomes fuel, the leftovers can be used for farming fertilizer. 

Flint has signed a 21-year agreement with Swedish Biogas, which means there's a lot of future left for this project. What does the future hold? Lots of promise, according to the U.S. Environmental Protection Agency. 

A study by EPA's Region 3 Office says "municipal sewage sludge is gaining traction in the U.S. and around the world as a lipid feedstock for biodiesel production. It is plentiful and consists of significant concentrations of lipids that can make production of biodiesel from sludge profitable."

There are challenges to production, but those may be overcome by methods like those described by Swedish Biogas, according to the research, which concludes "biodiesel production from sludge could be very profitable in the long run."

Not bad for a city that's been declared dead more than once. Can we call this brown energy? 

Image Credit: TheTruthAbout via Flickr.