Generating Power from Waste

7. Affordable and Clean Energy 9. Industry, Innovation and Infrastructure 11. Sustainable Cities and Communities 12. Responsible Consumption and Production


Exeter Agri-Energy, in conjunction with Stonyvale Farm and Biogas Energy Partners, installed a large scale anaerobic digester that is fueled by cow manure and food scraps. The electricity powers and heats the farm and the excess is sold on the grid. The food scraps are also a net benefit because they are diverted from the solid waste stream, using that resource at a higher net energy production.

"I loved how they blended the time honored tradition of dairy farming with cutting edge technology." - Greg Williams, Director of Waste Solutions at Agri-Cycle Energy


Owen Casas

Owen Casas


Case Western Reserve University - Weatherhead School of Management

Case Western Reserve University - Weatherhead School of Management


Ron Fry

Ron Fry


The innovation is the unique combination of traditional farming resources and its byproduct with cutting edge technology in anaerobic digestion. Additionally, diverting large scale food waste from landfills or waste to energy plants (read as burning trash to produce electricity) as an additive to the anaerobic digestion.

It is amazing what happens when you place a large amount of technical knowledge into the minds of young forward thinking farmers. Because of the existing skill set and resources built up in a 5th generation family farm and the desire to make use of abundant amounts of daily "waste" generated by the farm, using that "waste" to power aspects of the farm made anaerobic digestion viable. Although anaerobic digestion was not an obvious choice, it is clearly an innovative solution to a complex problem.

The Fogler family has been around and involved in Maine for a long time. One branch of the Fogler family are the Wintle's and this innovation was spearheaded by three Wintle siblings.

John Wintle is the project and facilities manager at Exeter Agri-Energy. He holds a degree in Bio-Resources Engineering Technology with an MBA from UMaine.

Adam Wintle was instrumental in launching Exeter Agri-Energy and is managing partner of Biogas Energy Partners, which manages the finances and strategic planning EAE. He holds a Mechanical Engineering degree from UMaine.

Sarah Wintle is communications and operations manager at Biogas Energy Partners. She has a duel masters degree in American and African-American Studies from Smith College.

Because the innovation isn't simply an anaerobic digester but how they aligned a digester with multiple aspects of their organization, this quote sums it up:

"I think the key ingredients in this case were (1) a common digester vision (2) marriage of development, financial, and operations skill sets across a diverse team (3) a willingness to assume risk and innovate and (4) general perseverance all the way to the finish line." - Adam Wintle, Managing Partner at Biogas Energy Partners

Generating Power from Waste


Dairy farming in Maine has always been physically difficult to keep going, but in today's market it is both physically and economically difficult to keep going. Three younger members of the family farm studied, respectively, Bio-Resources Engineering Technology, Mechanical Engineering, and American and African-American studies during college. To keep the family farm economically viable, they decided to join forces and spin off an organization that would power the farm using cow manure and food waste.

This was motivated by a desire to reduce overhead energy costs in the long term while gaining a net benefit from using their cow manure "waste" (up to 20,000lbs per day) as a fuel source. It was an effort to see if they could innovate themselves into a financially viable place to keep the dairy farming on stable footing while diversifying income streams.

This innovation fits well into the Stonyvale Farm mission of keeping a healthy stockyard for their herd to produce roughly 7,900 gallons of milk daily. It also fits with the family tradition of innovation. In fact, the Exeter Agri-Energy "tag line" is "tradition + innovation".

"I am proud that Adam Wintle had the foresight, vision, and action necessary to make the digester a reality. He saw that the dairy farming area was declining and took action to keep the farm alive. He was extremely innovative and, with this model, was first in this space." - Greg Williams, Director of Waste Solutions at Agri-Cycle Energy

Overall impact

One of the biggest impacts I see coming from this innovation is a new model for other working farms to use to remain financially viable. The impact of being first in this space and the risks they took should not be down played. In addition to all the environmental, social, and business benefits, showing that a farm can diversify their income streams by leveraging their resources will be hugely important for farmers in the coming years.

"I have been very impressed with the Exeter team's weird ability to want to share their success with others. Even with folks that are operating in this same space. The family has a strong inclination to share information if it benefits the greater good and continues to move us all forward. It makes us leaders in this effort. That said, our openness has been used against us by competitors. We all continue to want to share our successes with others but have had to consider this approach while being aware of the impact to us as a business." and "Adam and the Exeter team doesn't try to simply use a resource, they try to maximize that resource and use it to its fullest ability." - Greg Williams, Director of Waste Solutions at Agri-Cycle Energy

Business benefit

The business impact on Stonyvale farm is a cost savings on their operating costs in two main ways. 1, they no longer have to spend time and money on transporting cow manure to locations for storage and break down and 2, reducing overhead costs in the form of reduced cost of electricity (produced by a generator powered by gas from the anaerobic digestion) and reduced heating costs (also a byproduct of digestion). After digestion, the material is compressed, separating liquid from solid. The liquid is spread over the fields as an additive and the solid is used as bedding for the cows, which means the farm saves money by not having to purchase and ship in bedding.

Short-term effects include reduced operating costs for the farm, new economic activity around start up business, reduction of food waste in solid waste stream, and increased visibility for Stonyvale farm and EAE.

"In terms of community, the combined dairy and digester operation are the largest employer in the town of Exeter." - Adam Wintle, Managing Partner at Biogas Energy Partners

"We will be adding another natural gas generator (runs on gas generated from digester) which will double our energy generation from 1MW to 2MW. We also plan to expand up to our maximum permitted energy production of 3MW overtime. Along those lines, we plan to increase where the heat from digestion goes around the farm, which will reduce our energy consumption further, saving us financially over the long term and benefiting the planet." - Greg Williams, Director of Waste Solutions at Agri-Cycle Energy

Social and environmental benefit

Environmentally, electrons now flow into the farm and the grid from a renewable source. Cow manure also produces a large amount of methane gas, which adds to the overall greenhouse gasses. These gasses are the fuel source for power production, reducing overall emissions. The food waste collections, an additive to the cow manure in digestion, also takes organics out of the solid waste stream. This means that the food waste doesn't make it to waste to energy (WTE) plants, which burn the solid waste to produce power. This provides a better fuel source for WTE plants because food waste doesn't burn efficiently and is better used in compost or digestion.

The local economy has benefited from this innovation by providing more jobs related to the EAE digesters and food waste collection. Economically, Stonyvale is in a better place which allowed them to maintain and, in the future, expand their workforce specific to the farm. Stonyvale puts more people to work in Exeter than any other business.

"From an environmental viewpoint, we are eliminating foul odors in the region, eliminating significant levels of harmful greenhouse gases, repurposing food waste by creating a cheaper, cleaner disposal solution, and producing renewable energy powering hundreds of homes in New England." Adam Wintle, Managing Partner at Biogas Energy Partners

"What could be a harmful thing for the planet, we are turning into a net benefit." - Greg Williams, Director of Waste Solutions at Agri-Cycle Energy


Greg Williams, Director of Waste Solutions at Agri-Cycle Energy

Greg Williams, Director of Waste Solutions at Agri-Cycle Energy

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Exeter Agri-Energy

Exeter Agri-Energy

Exeter, ME, United States

Business Website:

Year Founded: 1999

Number of Employees: 11-50

Exeter Agri-Energy, in conjunction with Stonyvale Farm, Biogas Energy Partners, and Agri-Cycle Energy, installed anaerobic digesters that produce heat and electricity for the farm and to sell on the grid and the fuel source is a mixture of cow manure and food waste. This helps power and heat a working farm that milks 1,000 dairy cows a day.