Clean energy provider Entech Solutions and renewable gas producer Northern Biogas have cut the ribbon on a repurposed, anaerobic biodigester facility. The manure digesters in Middleton formerly produced electricity. With support from Dane County, the three digesters now produce RNG using manure from four area dairies.
The facility incorporated advanced technology, including a nutrient concentration system that returns clean water to the region’s Yahara Watershed while also reducing phosphorus runoff to nearby streams and lakes. In 2021, over 27 million gallons of manure was processed by the biodigester, removing more than 57,000 pounds of phosphorus from the watershed.
“Water and soil are essential to life on earth, and farmers continue to look for opportunities to improve water quality and soil health,” says Jeff Endres, co-owner of Endres Berryridge Farms. “Northern Biogas and EnTech Solutions have opened up high-tech opportunities around dairy manure, working with area farmers to harvest the methane and return the fiber and liquid nutrients back to the farmers for use as organic fertilizer and bedding, maximizing all aspects of the nutrient cycle.”
EnTech Solutions incorporated a renewable energy microgrid at the facility, featuring solar panels and batteries which provide more than 2.8 MW of clean energy generation, the equivalent of powering more than 400 homes. This creates a carbon negative process that results in RNG with a lower carbon intensity score. Overall, the facility will reduce emissions by more than 13,500 metric tons per year of carbon dioxide equivalent. The reduction is equivalent to removing emissions of nearly 34 million miles driven by cars.
“Partnering with EnTech Solutions, Northern Biogas and our family-owned dairy farms paves the way for home-grown renewable energy, cleaner lakes and keeping our farm families milking cows for generations to come,” says Dane County Executive Joe Parisi. “This new investment in cutting-edge technology benefits both the local environment and our farm economy while combating climate change.”
The facility’s RNG is trucked to Dane County’s landfill offload station, where it is injected through the county’s equipment into the interstate transmission pipeline to be used as renewable fuel to power fleets of RNG vehicles. U.S. Gain, a division of Wisconsin-based U.S. Venture, Inc., and a leader in the development and distribution of alternative fuel, offtakes the RNG and markets it to the transportation sector in California. RNG from cow manure can reduce greenhouse gas emissions up to 400 percent when used to replace traditional fossil fuels.
“Using our experience in engineering and energy technologies, we were able to convert the Middleton facility to an even more efficient producer of clean RNG, and accomplished this in a compressed timeframe,” says Scott Romenesko, EnTech Solutions president. “We know this is a replicable process that we can apply to help other biodigesters achieve their environmental goals.”
“We saw the Middleton project as a great opportunity to leverage our 18-year history working with anaerobic digesters and nutrient management to support EnTech Solutions in their mission to create sustainable, reliable energy solutions,” says Northern Biogas president Dave Fitch. “Together we share a passion for innovation and a commitment to clean energy. Along with the support of Dane County and the local community, we think these new systems and technologies will make a positive impact for the farmers and the surrounding environment.”
Vice president of engineering Jeff LaViolette shares more about the project and the quantity of manure coming in and natural gas leaving the facility:
