From an article by Steve Cahalan in the La Crosse Tribune:

With the flip of a switch Wednesday, a new renewable energy system at City Brewery’s wastewater pretreatment plant began generating electricity from methane gas previously flared off as waste.

The Gundersen Lutheran-owned system resulted from a unique partnership between the health care provider and the brewery.

It is part of Gundersen Lutheran’s plan to lower its energy costs and be energy independent by 2014, through conservation efforts and renewable energy projects.

The brewery project is expected to generate about

3 million kilowatt hours a year, about 8 percent of the electricity used at Gundersen Lutheran’s La Crosse and Onalaska campuses. That also is enough electricity to power 299 homes, Gundersen Lutheran officials said.

With the new system, biogas from the brewery’s pretreatment plant is cleaned by removing water and impurities. What’s left is methane gas that is burned in the system’s engine.

Heat generated from the engine is captured and recycled back to produce heat for the brewery’s waste treatment process.

Brewery waste goes to its pretreatment plant before being sent to the city of La Crosse’s nearby wastewater treatment plant. Gundersen Lutheran officials said Wednesday it’s possible that biogas from the city’s plant also might be used to create electricity in the future.