Dane County’s Renewable Natural Gas Station received its first delivery of biogas from the Town of Vienna manure digester Thursday, the result of a project that will allow 90,000 gallons of manure per day to be converted into vehicle fuel.
It marked the first load of RNG produced from a manure digester in the Yahara Lakes watershed. The biogas will be trucked to the county’s offload station and injected through the county’s equipment into the interstate transmission pipeline to be used as renewable fuel, powering fleets of RNG vehicles.
Brightmark, which purchased the digester from Clean Fuel Partners, completed construction of a multi-million-dollar upgrade to the plant just north of Waunakee to convert methane captured from manure into biogas. Eventually, the facility’s capacity will be increased as well, when all three digesters there become operational.
Infrastructure is already in place to build a fourth digester, said John Welch, the county’s Department of Waste and Renewables director. Welch said Brightmark is in discussion with other farmers to receive more manure and help with their management.
Dane County Supervisor Dave Ripp, who represents the Town of Vienna, noted that the upgrade, which allows the digester to convert methane to RNG rather than energy for Alliant Energy as it did in the past, increase profits. Ripp said under the contract with Alliant, the digester was earning about 9 cents per kilowatt hour, but that price was to drop significantly under a new contract with the utility.
“There was a lot of worry about the financial stability and if they were going to have the farmers pay more,” Ripp said.
The digester is now making 80 cents per kilowatt hour, according to Ripp.
“That’s a huge difference,” Ripp said. “That puts them financially in outstanding shape. All that talk about the farmers having to kick in more is gone.”
Announcing the first fuel delivery June 11, County Executive Joe Parisi said the project will help prevent greenhouse gas emissions from entering the atmosphere and significantly reduce phosphorus runoff into the lakes.
“I am hopeful that revenue from the sales of digester RNG will spur the development of more digesters and increase our lake clean-up efforts,” Parisi said.
With state and private funding, Dane County contracted for construction of the state’s first community digester in 2010. It receives manure from three family farms, preventing phosphorus-laden runoff and improving area lake quality.
Brightmark’s investment will create both long-term project viability and increased manure treatment from additional dairy farms, county officials say.
“The project demonstrates the power of a great partnership having significant positive environmental impact,” said Bob Powell, CEO of Brightmark. “We are excited for this work to come to fruition, as it will positively impact not only the climate but also the regional economy.”
RNG drastically reduces greenhouse gases associated with agriculture. During the anaerobic digestion process, methane is captured as biogas and converted, rather than being released directly into the atmosphere, according to a release from Dane County.
“Research shows that when all climate benefits are considered together, RNG from dairy manure can reduce GHG emissions 400% when it is used to replace traditional vehicle fuels,” the release states.
It notes that every trailer that comes through Dane County’s offloading station will reduce greenhouse gas emissions equivalent to that of burning 24,000 pounds of coal.
The digester is estimated to deliver a trailer of gas to the landfill every two to three days.
The county’s offloading project was part of the 2018 budget and cost approximately $5.5 million for design, permitting and installation. Users will be charged a fee to pay back the cost of the installation and fund the facility’s operation. Price incentives are available for digesters in the Yahara Watershed that participate in the advanced phosphorus removal to further help incentivize area lake clean-up.
In April, the county announced the first delivery to the RNG station from a digester in Fond du Lac County. Dane County has the capacity to unload approximately 20 million gallons of gasoline equivalent per year.