Reducing Agricultural Methane

Agricultural activity is one of the largest anthropogenic sources of methane emissions globally and is the largest source in the US, responsible for the release of 10 million tons of fugitive methane in 2020.  Methane emissions from US agriculture are mostly released by livestock—approximately 24% from manure management systems, and 70% from enteric fermentation, a digestive process which causes animals to produce and expel methane. A diverse array of solutions are being deployed to mitigate methane emissions from manure, while emissions from enteric fermentation remain practically unaddressed.

Livestock Emissions Estimates

"This project aimed to advance the adoption of cover-and-flare systems on manure management systems at US livestock farms, by working with carbon offset methodologies to amend standards of additionality, and create a standard which conservatively but justly credits farmers for methane destruction projects.

In 2023 we paused our manure management methane research due to unclear economic viability for mitigating methane from small to mid-sized farms. If we find new potential solutions in this space, we will take this research line back up."

Total Potential near term goal
Risk-Adjusted Near-Term Project Goal
Potential Near-Term Project Goal
from program Anthropogenic

Manure lagoons are an emissions challenge

Depending on the size of a livestock farm and its management style (i.e. whether animals are confined or free-ranging), strategies to manage manure often involve a combination of spreading on fields to supplement fertilizers, composting, long-term storage in lagoons, and anaerobic digestion. Of these options, lagoons are the cheapest solution for storing large volumes of manure on a small spatial footprint, and are the most prevalent manure management system adopted on large farms in the US. Open-air lagoons are responsible for the majority of manure management methane emissions, predominantly at large hog and dairy farms.

Cost-effective abatement

The most cost-effective and reliable way to mitigate long-term methane emissions from manure lagoons is to install gastight covers and flare the captured gas. Equipment and materials required for cover-and-flare systems are cheap, durable, and require minimal maintenance. In addition, this approach avoids fugitive emissions associated with running a gas-powered generator or upgrading biogas for pipeline injection.

Risks & Risk Mitigation

Adoption hesitancy

A widespread first round of anaerobic digester projects was launched by the USDA in the 2000s, most of which subsequently failed due to technological or economic reasons. Most of these projects were partially financed by farmers, who also ran and maintained the digesters in addition to their day-to-day operations. These digesters often became more expensive to maintain than originally projected, and more time intensive to manage. Some became too difficult to repair when original manufacturers or installers went out of business.

Farmers are wary of investing more of their own time and money to install the next generation of digesters now. Further, financing cover-and-flare projects via the sale of carbon offsets, as has been widely proposed, is an untried approach. Even if funding is available from state and federal agencies for new digester installation, many farmers would like to see a successful pilot project before taking on the risk themselves. There may be limited opportunities for the CC Lab to promote the adoption of cover-and-flare systems short of developing a project with a key industry collaborator.

Fragmented market

Dairy production occurs across the United States in various regions and communities, each with distinct farming histories and market considerations. To overcome adoption hesitancy around anaerobic digesters, as previously described, successful pilot projects may be needed in multiple locations to inspire follow-on projects. A successful project in New York may be unlikely to inspire confidence among dairy farmers in Oregon, for example. 

Due to the fragmented nature of the market, it may be more difficult for CC Lab-supported pilot projects to have a wide impact, and reinforces the need for a strong industry partner.

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