Renewable natural gas (RNG) projects capture methane from animal manure to create a low-carbon, waste-derived fuel to power vehicles and buildings. The latest data shows that U.S. farms are capturing 166% more biogas than what was captured five years ago, processing 25 billion gallons of manure annually. For dairy farmers, these projects are an economically sustainable practice that redirects methane from the environment.
Progressive Dairy Editor Jenn Coyne connected with Geoff Dietz, senior director of federal government affairs with the Renewable Natural Gas Coalition, to learn more about how this alternative energy sector has evolved to its current state in the U.S. dairy industry.
What is the current landscape of RNG production on U.S. dairy farms?
DIETZ: The majority of RNG projects are located at medium and large dairy farms. These projects represent more than 20% of RNG production capacity in North America and nearly 60% of total operational projects. The U.S. dairy RNG sector has grown rapidly over the past decade and is now one of the fastest-growing segments of the RNG industry. Most projects are concentrated in major dairy regions such as California’s Central Valley, as well as Idaho, Wisconsin, Michigan and South Dakota, where large herd sizes and supportive infrastructure have helped drive development.
The industry has evolved from smaller electricity-focused digesters into sophisticated pipeline-quality RNG systems that capture methane from manure and convert it into low-carbon transportation fuel. As demand grows for low-carbon fuels, dairy RNG is increasingly being viewed not only as a methane mitigation solution but also as a long-term revenue and sustainability platform for American dairy producers.
Geoff Dietz. Courtesy image.
How has this alternative energy sector evolved?
DIETZ: The dairy RNG sector has evolved rapidly over the past decade from a niche manure management solution into one of the fastest-growing segments of the U.S. renewable fuels industry. Early dairy digesters were often focused primarily on electricity generation and odor control, but the emergence of strong low-carbon fuel incentives – particularly the U.S. Environmental Protection Agency’s Renewable Fuel Standard and California’s Low Carbon Fuel Standard – dramatically improved the economics of upgrading biogas into pipeline-quality RNG for transportation fuel use.
Advances in digester technology, gas upgrading systems and centralized cluster projects that aggregate manure from multiple dairies have also helped scale deployment and reduce costs. RNG producers are also increasingly pursuing mixed feedstock projects which combine dairy manure and locally-sourced food waste from rural communities. This approach allows smaller, family-owned dairies to participate in RNG projects where previously those farms would be unable to source sufficient amounts of dairy manure to make a project economically viable.
At the same time, growing pressure from food companies, investors and policymakers to reduce methane emissions has elevated dairy RNG as a practical climate and sustainability solution for agriculture. Today, dairy RNG is increasingly viewed not only as a methane mitigation strategy but as a long-term rural infrastructure and energy platform capable of generating new revenue streams while supporting low-carbon fuel markets in North America.
How can dairy producers leverage abundant RNG resources to reach sustainability goals and provide an additional source of revenue for the farm?
DIETZ: By capturing methane emissions through anaerobic digesters and upgrading the biogas into pipeline-quality RNG, farms can significantly reduce greenhouse gas emissions, improve manure management and support sustainability commitments. RNG also creates an additional long-term revenue stream through fuel sales and environmental credit markets, helping diversify farm income beyond milk production alone. Dairy manure-derived RNG can achieve negative carbon intensity scores under life cycle accounting frameworks, making them among the lowest-carbon transportation fuels available today. As demand grows for low-carbon fuels in transportation and diverse alternative markets, dairy RNG is positioning farms to play an increasingly important role in both rural economic development and America’s clean energy future.
Where does the future lie for RNG production in the dairy industry?
DIETZ: We estimate that less than 10% of all operating U.S. dairy farms that could independently economically support or contribute to cluster RNG projects are currently doing so. The industry is aggressively pursuing diverse, alternative markets for RNG in addition to heavy-duty transportation to help support bringing additional projects online. Additionally, the economics of dairy RNG projects benefit from the ability to monetize multiple output streams generated in the fuel production process. In addition to RNG itself, operators are interested in developing structured off-take strategies for biogenic CO2 and digestate-based fertilizers. Securing commercial agreements across these product streams can enhance revenue diversification and strengthen project resilience.
