Wilmarth Plant

Location: Mankato, Minnesota, on the Minnesota River

Plant Description: Wilmarth is a two-unit generating plant that burns processed municipal solid waste, called refuse-derived fuel (RDF).

Power Production Capability: (in-service dates) Total – 19 Mw: Unit 1 – 10 Mw (1948); Unit 2 – 9 Mw (1951)

Fuel Sources: Refuse-derived fuel (RDF), a fluffy, burnable fuel produced at resource recovery facilities in Newport and Elk River, Minn. Although Wilmarth uses an alternate fuel, it produces electricity the same as conventional plants – a source of heat turns water to steam, which drives a turbine-generator.

Plant History: Wilmarth proves that a combination of ingenuity and technical advances can offer innovative solutions for today’s waste disposal problem. Built in the late 1940s as a coal-fired generating facility, Wilmarth’s two units were converted in 1987 to burn RDF. The processed municipal solid waste provides a low-cost fuel alternative to generate electricity and reduces the amount of material going to landfills.

Wilmarth is named after George Wilmarth, who served as chief operating engineer for Northern States Power Company, a predecessor to Xcel Energy.

Interesting Features : The RDF burned at Wilmarth is produced at resource recovery facilities in Elk River and Newport, Minn. These facilities collect and process approximately 790,000 tons of municipal solid waste each year from several Minnesota counties. Haulers dump solid waste on the tipping floor at the facilities. Front-end loader operators then inspect trash and push it on the floor to a feed conveyor. The RDF processing facility removes recyclable materials and non-combustible items from the waste, then chops and shreds it into a uniformly sized fluffy product for delivery to Wilmarth, or its sister RDF combustion plant in Red Wing, Minn.

RDF is hauled by truck to a receiving facility at the Wilmarth plant, where it is conveyed to the two boilers inside the plant.

Environmental Highlights: The plant employs a scrubber and baghouse to effectively reduce emissions from burning refuse-derived fuel. The scrubber treats flue gas with a water spray and lime slurry, while the baghouse traps particulate by forcing gas streams through large filter bags.

Contact Information:

• Plant Information and Tour Requests — 1-800-895-4999
• Media Inquiries — 612-215-5300