Biogas Resource Library – Dangers of Large-Scale Biogas Digesters

Quick Facts

  • Factory Farm Gas: What it is and why it’s harmful (Farm Aid, 2024) – An explainer from Farm Aid describing how so-called “factory farm gas” (biogas from manure) is pitched as a climate solution but in reality it further entrenches unsustainable factory farming, creates huge amounts of pollution, and increases greenhouse gas emissions. Includes a clear overview of how digesters work and bullet points on why manure biogas is harmful (e.g. concentrated toxic waste in “digestate,” air pollutants similar to fossil fuels, and increased risk of leaks and spills).

  • Debunking Delaware Biogas: The Truth Behind Industry Lies (Food & Water Watch, 2022) – A myth-busting article that breaks down common biogas industry claims. It explains that anaerobic digesters won’t magically eliminate factory farm pollution – the leftover waste (“digestate”) still contains most of the original manure’s pollutants and can contaminate water just the same. It also shows that biogas is functionally the same as fracked natural gas (mostly methane) and is transported and used in the same way, meaning it’s no cleaner or more renewable than fossil gas.

  • Manure biogas is a climate smokescreen for big agriculture (Friends of the Earth, 2025) – A blog post by FOE’s food and agriculture campaign highlights how “factory farm gas” is a greenwashing tactic by Big Ag and Big Oil to profit off pollution. Manure biogas is marketed as “renewable energy,” but in fact it does little to curb emissions and instead enables industrial CAFOs to keep polluting and harming public health. The article also discusses how taxpayers are unwittingly subsidizing this false solution and recounts stories from rural community members who have fought biogas projects.

  • Biogas Production in U.S. Dairy Farms
    Analyzes trends in biogas output from dairy operations, with attention to emissions, efficiency, and regional policy incentives.
  • U.S. Dairy Biogas Digesters by County
    National map illustrating digester clustering and growth patterns among dairy operations.

Health & Environmental Risks

  • We Can’t Let This Gas Greenwash Polluting Factory Farms (Food & Water Watch, 2023) – This explainer details the environmental and health downsides of large-scale “biogas” digesters. It notes that factory farm gas is a dirty energy source: burning biogas emits the same dangerous air pollutants as burning fossil fuels, including ammonia, hydrogen sulfide, and smog-forming NOx. Digesters and their gas pipelines also inevitably leak methane, making the full biogas supply chain even “leakier” (and thus more climate-damaging) than the fracked gas system. In short, diverting manure to energy increases pollution and greenhouse emissions instead of reducing them.

  • Why isn’t factory farm gas the solution to the industry’s waste problem? (Food & Water Watch, 2024) – An article explaining that manure digesters are not an effective solution for factory farm waste or climate pollution. Even at peak efficiency, digesters only capture a portion of emissions and do nothing to address methane from cows’ digestion (enteric fermentation). Meanwhile, digesters can exacerbate local environmental injustices – they release air pollutants like nitrogen oxides and sulfur dioxide that contribute to respiratory illnesses, smog and haze in rural communities. The piece makes clear that treating symptoms (manure gas) instead of the root problem (factory farm expansion) leaves communities with ongoing water contamination and air quality problems.

  • “A Brown Cloud Over the Golden State” – How Dairy Digesters Are Driving CAFO Expansion and Environmental Injustice in California (Friends of the Earth et al., 2024) – Report on the impacts of California’s dairy biogas boom. It documents how heavily subsidized manure digesters in California’s Central Valley have spurred the growth of mega-dairies, worsening pollution in already vulnerable communities. For example, in Tulare County (which has one-third of CA’s dairy cows), digester projects have “exacerbated air and water pollution” in predominantly Latino rural neighborhoods. The study calls this out as environmental injustice and notes that people of color in CA are far more likely to live near these polluting factory farms. It underscores that state incentives for “renewable gas” have effectively financed more CAFO expansion to the detriment of public health.

  • Making a Bad Situation Worse: Manure Digesters at Mega Dairies in Wisconsin (Friends of the Earth & SRAP, 2024) – An investigative report and case study from Kewaunee County, WI, showing that biodigesters actually worsen industrial farming’s impacts. Data show that dairy CAFOs with digesters dramatically expanded their herds (by 58% on average) after installing digesters, leading to more manure, more methane, and more pollution in the area. The report found that every digester-equipped mega-dairy in the county had at least one manure spill (one had 23 spills) and saw increased ammonia emissions and damage to local roads from heavy tanker traffic. Residents conclude that digesters are merely “a perpetuation of the problem rather than a solution,” and the report recommends halting public incentives for manure biogas in favor of truly sustainable farming.

  • Health and Environmental Impacts of Biogas Summarizes health and ecological risks of large-scale anaerobic digesters, including air pollutants and water contamination from digestate.
  • Manure Biodigesters, Methane, and Agricultural Greenwashing  Legal critique of how manure-to-gas schemes misrepresent sustainability and lead to expanded industrial agriculture.
  • Critical Review of Renewable Natural Gas in Climate Discourse
    Scientific critique of RNG’s touted climate benefits, pointing to lifecycle emissions and policy blind spots.
  • Renewable Natural Gas: A Climate Risk Analysis
    Shows that RNG systems can have high carbon intensity due to methane leaks and upstream emissions.
  • Environmental Impacts of Co-Digestion: Organic Residues and Manure
    Examines how co-processing organic wastes in digesters affects emissions, chemical leaching, and operational complexity.

Follow the Money (Subsidies & Industry)

  • The Big Oil and Big Ag Ponzi Scheme: Factory Farm Biogas (Food & Water Watch, 2024) – A deep-dive report mapping the alliances and funding behind the “factory farm gas” industry. It reveals how major fossil fuel and agribusiness corporations are teaming up to invest in biogas and painting it green to sustain their polluting operations. The report details how massive public subsidies and favorable policies (from state fuel programs to federal spending bills) have created a profitable manure-to-gas frenzy for corporate polluters. In effect, taxpayer money is fueling a scheme that makes manure a commodity – “making producing food a byproduct of a profitable manure industry” – while the promised climate benefits fail to materialize.

  • No Clean Electricity Tax Credits for Dirty Manure Biogas (Earthjustice, 2023) – A policy brief arguing that manure biogas should not qualify for federal clean energy tax credits. Earthjustice (joined by dozens of environmental and justice groups) urged the Treasury to exclude biogas power plants from Inflation Reduction Act credits intended for zero-emission electricity. This piece explains that while digesters are billed as “clean” energy, there is nothing clean about biogas. When accounting for the full lifecycle – from growing animal feed to methane leaks and combustion – biogas systems still emit tremendous greenhouse gases. In short, public funds for climate solutions should not prop up **an industry that ultimately increases emissions and pollution in frontline communities.

  • “A Brown Cloud Over the Golden State” – How Dairy Digesters Are Driving CAFO Expansion and Environmental Injustice in California (Friends of the Earth, SRAP & LCJ&A, 2024) – This report exposes how California’s climate policies (like the Low Carbon Fuel Standard) have become a cash cow for mega-dairies. It shows that the state’s generous carbon credits and grants for dairy biogas have funneled millions of dollars to large dairy CAFOs, effectively subsidizing their expansion. Meanwhile, the “green” subsidies yield disproportionate harm to rural communities: the study notes extensive air and water pollution in digester-heavy regions, which are predominantly low-income and communities of color. FOE argues these public funds would be better spent on real climate solutions, not “giving public handouts to some of the state’s largest polluters.”

  • Making a Bad Situation Worse: Manure Digesters at Mega Dairies in Wisconsin (Friends of the Earth & SRAP, 2024) – A revealing investigation into how government incentives drive factory farm gas projects. In Wisconsin, digester subsidies and fuel credits (like the Renewable Fuel Standard and California’s LCFS) created “perverse incentives for [large farms] to maximize methane” production for profit. This report links those incentives to rapid herd growth on digester-equipped dairies (far outpacing other farms) and documents how subsidies reward polluters while failing to deliver significant net emission reductions. It concludes that biodigesters are a “greenwashed corporate handout” that encourages consolidation and pollution, diverting funds from truly sustainable agriculture.

  • Biden climate law could expand controversial biogas industry (Reuters News, 2022) – A news report on how the Inflation Reduction Act’s provisions support biogas. The article explains that the IRA offers new tax credits and ~$10+ billion in funding that the biogas industry hails as a huge boost. However, many environmental groups warn that these incentives will mainly benefit large factory farms: digesters are only economical at industrial scale, so subsidies could encourage big CAFOs to grow even larger, worsening manure pollution and runoff. An environmental justice lawyer notes that when you “dig into the details” biogas is not clearly a climate win, underscoring the risk of public money entrenching an unsustainable status quo.

  • Factory Farm Gas: A Ponzi Scheme by Big Oil and Big Ag  Exposes how subsidies for manure biogas benefit polluting industries while worsening environmental and public health conditions.
  • Biogas and the Circular Economy: Pennsylvania Case Study
    Explores whether biogas truly contributes to circular agriculture or reinforces centralized waste systems.
  • Economic Opportunities for Manure Management on U.S. Farms
    Highlights how financial pressures and incentives shape manure handling decisions on American farms.
  • Cost Estimation for Dairy-Based Biogas Systems
    Presents models for estimating capital and operational costs of dairy manure digesters under various scenarios.
  • RNG from Agricultural Waste: The Financial Drivers
    Dissects the economics behind RNG projects, revealing how public funding creates artificial markets.

Technical Overviews (How Biogas Digesters Work)

  • How Does Anaerobic Digestion Work? (US EPA AgSTAR Program) – A neutral primer from the EPA explaining the basic science of anaerobic digesters. It outlines how bacteria break down organic matter (manure, food waste, etc.) in an oxygen-free tank called a reactor, producing biogas (a mixture of methane and carbon dioxide) and a leftover slurry called digestate. The page includes a simple diagram of the inputs (waste) and outputs (biogas and digestate), and notes that biogas can be used like natural gas for energy or heating.

  • Renewable Natural Gas Production (U.S. DOE Alternative Fuels Data Center) – A fact-sheet on how raw biogas from landfills or digesters is upgraded into RNG (Renewable Natural Gas). It describes the technical steps: after anaerobic digestion, the biogas can be purified by removing impurities such as hydrogen sulfide, carbon dioxide, and moisture. At this stage the upgraded gas is called biomethane or RNG, which is nearly pure methane. The overview explains that RNG is pipeline-quality gas interchangeable with conventional natural gas, often used as vehicle fuel or for injection into gas grids. (This resource helps understand the engineering side of biogas utilization, separate from its environmental impacts.)

  • EPA AgSTAR Project Development Handbook – Anaerobic Digester Systems
    Comprehensive technical and planning manual for developing farm-based anaerobic digestion systems.
  • EPA Funding Guide for On-Farm Anaerobic Digestion Projects
    Outlines federal and state funding opportunities, tax credits, and financial considerations for digester construction.
  • EPA Overview of Renewable Natural Gas from Biogas
    Explains how biogas is processed into pipeline-quality RNG and the regulatory framework for its use.
  • Methane Emissions Across the Biogas Supply Chain
    Demonstrates that methane leaks from digesters and related infrastructure rival or exceed natural gas systems.
  • Technology-Based Methane Losses from Biogas Plants
    Breaks down methane loss by digester type and design, providing data on efficiency and leakage risks.
  • Microbiological Processes in Anaerobic Digestion Systems
    Focuses on the biology of digestion, showing how microbial dynamics influence methane production and waste treatment outcomes.

Nebraska Resources

  • Nebraska Department of Environment and Energy (NDEE) -  Nebraska's Agency focused on protecting and improving human health, the environment, and energy resources.  They are the main agency that is tasked with monitoring issues related to Confined Animal Feeding Operations (CAFO). They have a multitude of resources to help you monitor their adverse impacts.
  • Poultry Litter and Stream Health Study -Analysis by the Nebraska Farmers Union Foundation found alarming trends. Despite public assurances from industry experts stating that dry litter would not leach into waterways, the analysis showed that there was an increase in the nutrient phosphorous. In excess, phosphorous can cause a condition called eutrophication, or toxic algae, which leads to the death of aquatic animal life from lack of oxygen and can be seen in surface water across the region and in the Gulf Coast. Increased phosphorous was shown to be connected to increased levels of pathogens in the seven monitored Nebraska waterways.  The analysis offers recommendations that advocate for increased testing, data, and cooperation to identify problem areas. The analysis also makes policy recommendations that should be implemented immediately to stop oversaturation and excessive leaching of litter.

Legal and Policy Resources