Biogas Alert! Biogas and Biodigesters

Written by Kim Dupre, a Clean Water Advocate in the St. Croix River Watershed

Due to billions of dollars in Federal monies, a manure/food waste biogas digester invasion is occurring across our country. Developers chasing tax credits, carbon credits, and other generous subsidies at state and local levels are in a mad dash to implement these across our rural and small-town landscapes.

What is a biogas digester? A machine that uses heat (and sometimes water) to break down manure/organic materials to produce methane, trap it, then use it for heat, electricity and (most recently) renewable natural gas.

Image of the St. Croix river
St. Croix River

As far as volumes go – typically what goes in a digester also comes out, but in a more concentrated form; besides the gas, a by-product of solids and liquids that have chemically changed from their original forms are left behind this process. Very simple and crude digesters have been used for decades to generate heat and/or power for machines, cooking, etc. Some producers have on-farm facilities to heat their own homesteads, power their equipment and would sell extra power back to their utility company. However, the current-day version of biogas digesters has turned this concept from a sustainability practice and put it on steroids, introducing global investors and industrial agriculture players into the mix, selling renewable natural gas (RNG) off-site as renewable energy and another farm income stream.

The story these current biogas developers like to tell is one of “sustainability” and “climate forward thinking” to change our fuel sources to something we had been “throwing away” and now can use to heat our homes. It all sounds so practical, inventive, and a “no-brainer.” All pluses and no minuses in this scenario – win, win, win & more wins!

However, it’s what they aren’t telling you that should raise a lot of concerns. These “biogas evangelists” usually don’t live in or near your neighborhood and they have taken a local, sustainability concept and turned it into a production and profit maker for global investors. That changes the game significantly and ultimately affects your water and soils.

I heard this same “sermon” nearly 25 years ago at my rural town hall in Emerald, Wisconsin. A local farmer was going to build a brand-new dairy with a manure biogas digester that would extract methane gas, truck it to a pipeline a few miles away, and treat the leftover water with a reverse osmosis system prior to discharging into wetlands behind the production area and spread solids on area fields – high in nutrients and perfect for crop production. This was the “future of dairy” in Wisconsin! A parade of experts along with Wisconsin DNR assured us all that “everything will be fine” – the dairy would be utilizing Nutrient Management Plans that would protect our waters, property values and way of life. We would be proud of the facility and “on the map” for dairy farmers nationwide! Sounded too good to be true.....

Fast forward 20 years and everything is NOT fine in Emerald Township. After two years of operation – the digester and water treatment system exploded and burned up – never to be used again. The new Town Hall well nearby is currently undrinkable – nitrates increased over 6-fold in just 15 years and consistently tests 3-4x higher than maximums allowed. The soil tests from fields receiving the digestate and other spreading from the dairy are 5-6x higher than UW recommendations for phosphorus to grow corn. E. coli in well waters, fish kills, and green lakes are not unusual in the area. To our dismay, despite repeated requests for intervention, neither Wisconsin DNR nor EPA nor Department of Health nor local officials have been willing or able to rectify these issues. Too many folks don’t drink their water in Emerald Township; some don’t even give it to their pets.

So you can imagine my skepticism when a new round of “biogas evangelists” showed up in St. Croix County, eager for Federal monies and tax/carbon credits in 2021 after the Biden Administration and Congress passed the Inflation Reduction Act. The country song of “the road to hell is paved with good intentions” kept coming to mind. Prior to these monies, biogas digesters were being pushed in California, who offered carbon credits even to other state’s biogas facilities, so there were a few of these dotted around our country. News reports of explosions, spills, shutdowns due to smell or inability to sustain production viability began appearing nationwide. Despite all the preaching of “this is newer technology” or “this works wonderfully in Europe,” it did little to convince me that progress had really improved this concept. As an IT Systems/Applications Analyst for 20 years – I knew that “new” technology rarely was all it promised.

The marriage of Big Ag and Big Energy companies is an intimidating presence in your community. They will sweet talk local politicians and farmers/landowners and dismiss anyone else who speaks against them as spreading disinformation, NIMBYs, or worse. I personally experienced this same “get with the program” admonitions. Others shared with me about phone calls made to their employers to “shut up” their employee who spoke out against the digester proposal. Letters written to local governments to “get on board” or “get sued.” All the while hiding their worst secrets. In my opinion, these are not the tactics of an industry that has the best interests of citizens at heart.

If one of these proposals comes to your town – it will divide your community. Family members will be on opposite sides, church services will become tense, chance encounters at the gas station, local restaurants, or grocery stores will be awkward at best. Kids will replicate what they hear at home on their playgrounds.

Despite the mantra that a digester will help the local farmer better manage his manure problem – the digester doesn’t incentivize stability or reduction in animal numbers – it actually increases them! This can best be summed up as... if you get paid for your pollution, you’re not going to stop polluting, especially when global investors and tax/carbon credits are involved. A local veterinarian told me at 10,000 cows, producers will actually make more money from the manure than the milk! Talk about the tail wagging the dog! While producers like to say that “nutrients” are not “pollution” – they CAN become pollution when over-applying them on fields. That degrades soils and water for the entire community and is nothing more than waste disposal at that point. Water moves – it doesn’t know fence rows, county lines, or state boundaries – your entire community & then some will be affected!

But there is hope to push back successfully on these proposals. In St. Croix County, Wisconsin – we faced down the largest biogas company in Europe – Nature Energy, owned by Shell Oil. Not just once – but three times! Here are five things we would recommend when a digester proposal comes to your neighborhood:

First off – your concerns are justified. A casual look through news articles on digester explosions, spills, and mishaps will validate your concerns (see links referenced above).

  • Nature Energy (owned by Shell Oil) denied any odor concerns until a council member found their Denmark website to sign up for “alerts” when their processing would be “stinky” and outside activities by neighbors discouraged.
  • Violations at existing facilities owned by Vanguard Renewables (owned by Black Rock) in Massachusetts and Vermont were never disclosed to township officials near Waupaca and were uncovered by diligent citizens.

Second – question EVERYTHING! In our experience, these companies send their Sales/Marketing/PR staff who cannot answer technical questions. Insist on answers to process and technical questions – the devil is in the details. Too often the guise of “trade secrets” is utilized to keep from giving details – but when public health and safety is at risk – details are needed. Check out the top 15 questions used by citizens in St. Croix and Waupaca Counties here.

  • Digesters will reduce some methane but increase other greenhouse and hazardous (to human health) gasses such as ammonia1, 2, volatile organic compounds3, nitrous oxide4 and hydrogen sulfide5.

  • Digesters, depending on the temperature used, can destroy only ~ 90% of disease-causing pathogens – but most of this research was done in laboratories – not in “real world” environments. Differences in weather patterns, soil types, crops, farming practices, etc. once digestate is spread on the fields could greatly alter any
    claims made6.

  • Digesters alter nutrients (nitrogen and phosphorus) to make them more “water-soluble” – meaning the plant can access them easier, but it also means they are more likely to end up in your ground and surface waters7. Add in the “flavor of the day” that co-digesters receive (depending on the source: food waste, food manufacturing waste, slaughterhouse waste, municipal waste or pharmaceutical waste, etc.)8 and that could include PFOS and microplastic compounds going into your soils and waters9.

Third – Do your math! Calculate their number of trucks, tonnages, etc. Ask about types of trucks (6 wheels or 18 wheelers). It will help you understand the true effect on your roads and the amount of leftover byproduct (“digestate”) getting spread on your fields. Do they have enough acres allotted? Who pays for road damage from the extra truck traffic? Nature Energy actually told us we “wouldn’t notice an extra 110 trucks/day in our town!” Also, find out if your local fire/first responders have training to deal with an explosion/fire in a digester. (HINT: Most biogas digesters have tall stacks – higher than most local fire departments can cope with.)

Fourth – Get to know your local Comprehensive Plan/Ordinances. Each township, village, or city in Wisconsin is required to have and update regularly a local Comprehensive Plan that describes what your town should look like, the types of businesses allowed & where, goals for long-term growth or development, etc. The verbiage in this document can help you deny entities that don’t fit those plans and will withstand legal scrutiny. This is the same for ordinances already on the books in your township. If needed, Conditional Use Permits could entail:

  • Limiting the size of facility or amounts brought into the digester.
  • Required reporting and monitoring (they won’t volunteer that info).
  • Agreements to no municipal waste, no industrial waste, no plastics (from food packaging).
  • Nutrients (digestate-solid or liquid) should not be applied to any field with a soil test above state guidelines for phosphorus.
  • A complete budget of nitrogen – from all sources – should be completed if byproducts (digestate) are applied to a field as accounted for in their Nutrient Management Plan.
  • Companies needing to show total nutrients coming out of the digester and where exactly they will be land spread – BEFORE permit approval. No mass balance calculations. Require landowner signatures ahead of time and make sure the acres needed are under contract. That is the standard for CAFOs.

Finally (& most importantly) – Find Your People! It is people power pressuring local officials that has the biggest effect. Pack out those meetings and public hearings. State your concerns via conversations, official hearings, LTEs, emails, social media, yard signs, billboards, etc. BUT SHOW UP IN PERSON at meetings. Numbers matter! Local officials usually want to “keep their chair” so they know if their constituents are upset – they won’t get re-elected. That’s exactly what happened in Emerald Township when our County Board Supervisor (who was also Chairman of the County Board) backed our digester project and refused to entertain any citizen dissent at County Board – he did not get re-elected in the next election!

There are many facets and issues with a manure or co-digester – too many to cover in one sitting. However....always remember....there are advantages/disadvantages to most everything in life, and this kind of proposal is no different. There are tradeoffs and/or downsides to these facilities – so get informed. Check out Biogas or Bull****? The Deceptive Promise of Manure Biogas as a Methane Solution and The Big Oil and Big Ag Ponzi Scheme: Factory Farm Biogas. There are plenty of people now who have “had their eyes opened” on these issues and there’s no going back. Reach out to to learn more no matter where you live!

  1. University of Wisconsin (2022)-
  2. Domingo et. al. (2021)-
  3. Zheng et al. (2019)-,Freons%20and%203%20sulfur%20compounds
  4. EPA (2023) -
  5. Anaerobic Digesters and Biogas Safety – Farm Energy (2019) –
  6. Burch et al. (2018)-
  7. Xiao (2016)-
  8. Penn State Extension-
  9. EPA (2021) Emerging Issues in Food Waste Management: Plastic Contamination, p.3 Credit: “’Greenwashing “Brown Gold’: A Critical Analysis of Anaerobic Digesters and California’s Neoliberal Environmental Programs in Wisconsin’s Dairyland” by Dr. Sarah D’Onofrio, June 2023