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Minnesota AD Facility Among the Nation's Largest

Food processing and agricultural waste converted into electrical power is now part of the electricity profile of Le Sueur, Minnesota, and 11 other municipal electric utilities that are members of the Minnesota Municipal Power Agency (MMPA). The Hometown BioEnergy facility, located in Le Sueur, has begun operation on schedule and is producing electricity from biogas created from agricultural and food processing waste.

According to MMPA, the 8 megawatt (MW) facility is the largest of its kind in the country to employ an anaerobic digestion (AD) process.

"Anaerobic digestion is a natural process where waste is heated in large tanks, and the microbial action results in methane biogas ," says Kelsey Dillon, the project director of the MMPA facility. "The process is similar to what happens in a home septic system, where microbes degrade and stabilize organic matter; but in our case, we heat the material to accelerate the production of biogas on a commercial scale," adds Dillon.

"At optimal times when the power is needed, we draw off the biogas from storage and use it to fuel the electrical generators on the plant site," she continues, adding that this ability to time power production is a significant advantage to the technology. While the electricity from the site will be consumed in Le Sueur, it is considered by state regulators to be part of the MMPA's total renewable energy supply.

According to state law, by 2025 utilities will be required to have at least 25 percent of their power generated through renewable means (such as wind, solar, hydro or biomass). The AD process results in two byproducts – a liquid that will become fertilizer for area farmers and dried solid fuel that will be sold to be burned in boilers.

Dillon says Hometown BioEnergy is working with area businesses and communities to identify waste that can be converted to energy rather than ending up in a landfill or applied to soil. MMPA board chairman Steve Schmidt, also a city of Anoka council member, says, "Homeowners and businesses who rely on our member municipal utilities will benefit from our mix of cost-effective and local renewable energy generation sources."

MMPA's management partner, Avant Energy of Minneapolis, managed the facility's design and construction. MMPA financed the $45 million facility through a combination of federal stimulus grants and municipal bond sales.

Dillon says, "This project is great for Minnesota and MMPA communities because it takes waste from Central Minnesota and converts it into electricity that is used locally and helps meet renewable energy requirements. "We also hope it serves as an inspiration for other renewable energy facilities of this type in the state and around the country," Dillon adds.

Article published in: http://www.rewmag.com/minnesota-anaerobic-digester-largest.aspx