Minnesota dairy converts waste from 2,000 cows into renewable fuel for pipelines

On a 55-acre farm in rural Minnesota, manure from more than 2,000 milking cows is being transformed into ultra-low-carbon vehicle fuel that enters the national natural-gas pipeline. The Ash Grove Dairy plant, constructed by Dynamic Renewables and backed by a $22 million joint venture headed by Clean Energy Fuels Corp, runs anaerobic digesters that process up to 60,000 gallons of waste per day, capturing methane and removing impurities to produce biomethane identical to conventional natural gas.

At full output, the facility is slated to deliver about 480,000 gasoline-gallon equivalents of negative-intensity fuel annually, which Clean Energy Fuels supplies to transit buses, municipal trucks and freight fleets across North America. The project, highlighted by Biofuels Digest and Farm Progress, marks Clean Energy Fuels’ fifth RNG installation in nine months, reflecting growing demand for low-emission transport fuels.

By preventing methane release, the digesters earn a negative carbon intensity rating under standards such as California’s Low Carbon Fuel Standard. The remaining digestate is repurposed as animal bedding, soil conditioner, or low-odor fertilizer, offering dairy farms an additional revenue stream while improving nutrient management.