Food waste to heat Wisconsin university building

The University of Wisconsin Oshkosh (UWO) will convert food waste into heating for the campus services building.

The project, which will be funded by a $339,000 (€308,000) grant from the Public Service Commission’s (PSC) Energy Innovation Program, will connect the UWO Campus Services Center – home to its document services, facilities offices, postal services, shipping and receiving – to the adjacent dry anaerobic digester.

The digester currently produces about 8% of the university’s electrical needs by converting 10,000 tons of yard and food waste annually. The PSC project will allow the excess methane to generate more heat.

“Right now, all of the gas produced gets burned and what is produced is electricity and heat,” said Brad Spanbauer, campus sustainability director.

“We are not using the heat portion as efficiently as we could be, so that is what the PSC heat connection project will attempt to solve.”

Campus waste going to the digester includes all food waste from Blackhawk Commons, all pre-consumer food waste from Reeve Union, food waste from the Oshkosh Food Co-op that sells locally sourced and organic foods, yard waste from the Oshkosh campus, as well as from the City of Oshkosh and the Winnebago County landfill collection site.

Some waste comes from industrial sources. Every week, its largest industrial supplier, McCain Foods, supplies 20-25 tons of potato sludge and 50-60 tons of waste from breaded food.

It is hoped that the UWO biogas programme will someday make use of the energy in other ways, including the production of RNG.

“If we don’t need to use that energy during some months, we could perhaps funnel that into fuelling CNG or LNG vehicles such as those owned by the City of Oshkosh,” added Spanbauer. “This closes the loop by offering a fuelling site for renewable fuel made from food and yard waste on campus.”

Estimates suggest the converted methane gas will provide at least 75% of the heat being used at the Campus Services Center and provide average annual savings of around $24,000 (€21,800).