The production of energy from animal manure through anaerobic digesters, a process that captures methane emissions and produces “biogas,” has been touted as a significant component of the U.S. strategy to reduce agricultural methane emissions. Anaerobic digestion breaks down organic material, such as animal waste, in an oxygen-free environment, producing a mixture of gasses, mostly methane and carbon dioxide (biogas), along with a nutrient-rich byproduct called digestate. Biogas can be used to generate electricity, heat, or be processed into transportation fuel, making it attractive for reducing greenhouse gas emissions in a holistic way.

With the Biden administration’s commitment to the Global Methane Pledge and substantial financial support through the Inflation Reduction Act, manure biogas is positioned as a key climate change mitigation strategy. However, this report challenges this approach, arguing that it supports harmful industrial farming practices and fails to deliver on its environmental promises. The report critically examines how manure biogas production not only falls short in reducing methane emissions but also exacerbates environmental and public health injustices, particularly in marginalized communities.

The primary objective of the report is to provide evidence that the benefits of manure biogas for methane reduction have been overstated and inadequately tracked. The study reveals that policies supporting manure biogas production create incentives for factory farms to expand, encouraging practices that actually increase methane emissions and disproportionately harm low-income and minority communities. By incentivizing the use of anaerobic digesters, these policies end up promoting the expansion of factory farming and the adoption of manure management practices that maximize methane production rather than reducing it.

The report combines original research on herd size trends at dairy facilities with digesters, a review of federal and state policies incentivizing manure biogas, and case studies highlighting the environmental and social impacts of manure biogas production. The study also models alternative manure management practices, such as pasture-based systems and reduced herd sizes, which have the potential to reduce methane emissions more effectively than anaerobic digesters. These alternatives are presented as more sustainable and equitable approaches to addressing agricultural methane emissions.

The findings of the report indicate that dairy facilities with anaerobic digesters are likely to increase herd sizes at a rate significantly higher than state averages, contributing to a net increase in methane emissions rather than a reduction. This is particularly concerning given that methane is a potent greenhouse gas with a global warming potential 80 times greater than carbon dioxide over a 20-year period. The report also shows that the methane reductions achieved by manure biogas systems are insufficient to meet the Global Methane Pledge targets.

One key insight from the report is that manure biogas systems exacerbate rather than alleviate the harms associated with factory farms. These systems require large-scale, industrial farming operations to be economically viable, incentivizing the concentration of animals in confined spaces and the expansion of factory farms. This not only increases methane production but also leads to greater pollution of air and water, negatively impacting the health and well-being of nearby communities.

The report acknowledges limitations, such as the reliance on available data, which is limited due to insufficient government tracking and reporting on methane emissions from factory farms with digesters. This lack of transparency makes it difficult to fully assess the true impact of manure biogas on greenhouse gas emissions and environmental health.

For advocates, this report is valuable as it challenges the prevailing narrative that manure biogas is a green and sustainable solution to climate change. It provides a critical perspective on current policies and underscores the need for a shift toward more effective and just strategies for reducing methane emissions. The study concludes that promoting manure biogas as a climate solution is fundamentally flawed. Instead of mitigating climate change, it perpetuates the harmful practices of industrial animal agriculture and fossil fuel dependency.

The report calls for a shift in policy focus toward more effective and equitable methane reduction strategies, such as reducing herd sizes and supporting regenerative agricultural practices. Redirecting resources from manure biogas subsidies to truly sustainable energy and agricultural systems is essential for achieving meaningful progress in the fight against climate change and environmental injustice. Advocates can use these findings to push for policies that prioritize environmental justice and the well-being of both people and the planet over the interests of industrial agriculture and fossil fuel industries.