Sheboygan wastewater facility generates enough energy to be self-powered

From an article by Dan Benson in the Sheboygan Press:

Thanks to improvements made in recent months, the Sheboygan wastewater treatment plant is one of the few facilities of its kind — perhaps the only one in the nation — capable of generating enough energy to fully power its operation.

In fact, on weekends, when less equipment is operating and fewer people are working, the plant has generated an excess of electrical energy, which it sells back to Alliant Energy, according to Dale Doerr, wastewater superintendent.

"About a month ago, we were producing 115 percent (of the plant's energy needs)," Doerr said. "It turned the meter 'backward' for a time."

The city treatment plant is able to do that with the help of two 200-kilowatt micro turbines, which were installed in December with the help of a five-year $1.2 million loan from Alliant Energy's Shared Savings Agreement and $400,000 in grants from Alliant's Focus on Energy program.

The turbines run on "biogas" — methane gas generated by treated sewage. Exhaust from running the turbines also is used to heat water, buildings and the digesters at the plant, 3333 Lakeshore Drive.