Minnesota Dairy Turns Cow Manure into Renewable Natural Gas for Vehicle Fuel

A 55-acre dairy farm in Minnesota is now converting manure from over 2,000 cows into renewable natural gas (RNG). The facility at Ash Grove Dairy near Lake Benton processes up to 60,000 gallons of manure daily, capturing methane that would otherwise escape from storage ponds. The cleaned biomethane is injected into interstate pipelines and used as fuel for transit buses, garbage trucks, and freight vehicles. At full capacity, the project can produce around 480,000 gasoline-gallon equivalents per year. The project is a joint venture between Dynamic Renewables and Clean Energy Fuels, with a $22 million investment. It is the fifth RNG facility from Clean Energy Fuels in nine months, reflecting growing demand from fleets seeking lower-emission fuel. Because the digester prevents methane release, the fuel earns a negative carbon intensity score under California's Low Carbon Fuel Standard. The leftover digestate is separated into bedding and fertilizer, giving the farm extra income and better nutrient management. This is a practical example of turning agricultural waste into a climate solution. It cuts potent greenhouse gas emissions, provides a new revenue stream for dairy farmers, and supplies a cleaner fuel for heavy-duty transport. The project shows how manure management can shift from an environmental liability to a renewable energy asset.