Renewable electrical energy produced from anaerobic digesters could drive EV charging stations on dairy farms

Dairy Cow (Photo courtesy of ARS.)

One of the next climate change solutions might be found at your local dairy farm. A team of MSU researchers are studying ways to generate renewable energy from dairy farm waste to charge electric vehicles.

Wei Liao, a professor in MSU’s Department of Biosystems and Agricultural Engineering and the director of MSU’s Anaerobic Digestion Research and Education Center, led a demonstration workshop July 19 showcasing the novel research linking dairy operations to the auto industry. He was joined by MSU animal science professor Barry Bradford, BAE professor Ajit Srivastava, dairy farm manager Jim Good and BAE research specialist and ADREC manager Sibel Uludag-Demirer.

An electric tractor designed by Srivastava was showcased for its ability to operate on renewable electricity generated by a mobile renewable EV charging station with an anaerobic digester and an external combustion engine. Anaerobic digestion is the biological process where organic matter, like animal and food waste, is broken down in the absence of oxygen to produce biogas. The biogas can be burned to generate electricity and heat, or cleaned and used as renewable natural gas.

Although economic pressures have prompted part of the U.S. dairy industry to consolidate into large scale productions, the majority—90%—still operate at small and medium-sized enterprises of less than 1,000 cows.

Dairy is the leading agricultural commodity in Michigan. The industry accounts for nearly 5% of the state’s gross domestic product with $24 billion generated annually and supports over 111,000 jobs.

Michigan dairy also ranks sixth in U.S. dairy cash receipts, or the total amount of money earned from dairy products.

Liao said his hope is to implement mobile EV charging units on small and medium-sized dairy farms as the state continues shifting toward EV production to reduce carbon emissions from gasoline powered vehicles. He wants to give farmers in rural communities a way not only to charge their own EVs, but also to generate revenue doing it for other’s vehicles.

“We want to use this opportunity to link together the agriculture and auto industry,” Liao said. “They can both benefit from each other.”

Another reason Liao would like to introduce EV units on farms is to help encourage the dairy industry to become carbon neutral or have net zero carbon emissions. He said currently about 45% of the carbon in animal feed ends up in manure and is partially released as methane—a greenhouse gas (if not collected)—into the atmosphere.

If farmers can use the waste for high-value applications, like producing electricity and charging EVs, he said part of the climate problem becomes part of the solution.

“That’s just a win-win,” Liao said. “We can achieve the carbon neutrality of dairy farms and can similarly reduce emissions for the transportation sector.”

MSU converts food and animal organic waste from campus at its South Campus Anaerobic Digester. The digester, an above-ground steel tank capable of holding 450,000 gallons, has been in operation since 2013 and has digested roughly 60,000 tons of manure. In 2022, it digested 12,500 tons of manure from the MSU dairy farm and 15,000 tons of food waste from MSU’s cafeterias and the greater Lansing region.

The digester produces about 2.8 million kWh of electricity per year. Ten percent of that energy powers the digester itself, and the rest assists in powering 10 buildings across MSU’s south campus.

The mobile units Liao is working toward installing on small and medium-sized dairy farms won’t be as big and won’t be able to initiate the same amount of power as the SCAD. He said they’ll have the capacity to induce 30 kWh of renewable energy per day, or over 10,950 kWh of energy per year.

While that figure won’t be enough power to run an entire farm, Bradford said it could grant farmers different operational opportunities. For example, the energy from these units could charge batteries of emerging electric skid-steer loaders, or small low-power tractors used to clean animal pens.

“If you could charge (these tractors) yourself without paying a lot and having to deal with how you’re going to charge them, that could potentially be a game changer for how jobs are done on dairy farms,” said Bradford, whose role on the project is to understand how these units will impact dairy farms.

He also said electric charging stations on dairy farms could bring additional economic opportunities. As EVs become more popular and people look for places to charge them, dairy farms could become a viable option that allow visitors to charge their cars while also experiencing the work of local farms.

“Because it takes a little while to charge EVs, longer than it does to fill a tank of gas, farms can keep visitors occupied by selling them a sandwich or an ice cream cone. Maybe they can do a $5 tour of the farm,” Bradford said. “This could be a more mixed funding model where you have agritourism, energy and—of course—milk.” 

Sign up for HPJ Insights

Our weekly newsletter delivers the latest news straight to your inbox including breaking news, our exclusive columns and much more.

Funding for the projects comes from MSU AgBioResearch, along with the Michigan Economic Development Corporation, MSU Extension and the U.S. Department of Agriculture’s Agriculture Research Service. 

MSU professor making progress on an electric tractor for small-scale farming use 

Alongside the displayed mobile charging unit stood an EV from Bollinger Motors and Srivastava’s electric tractor. 

Srivastava, who’s been working on the tractor design since 2021, said it’s a light-duty tractor used for mild cultivation, spraying and weeding. 

Solar power and other forms of renewable energy, like the energy produced from anaerobic digesters, charge the batteries located underneath the tractor. 

“Our motivation was to design a tractor for light-duty work and weed control, especially for crop farmers who run small farms and want to be sustainable,” Srivastava said.

The tractor was funded by Project GREEEN, Michigan’s plant agriculture initiative housed at MSU and spearheaded by plant-based commodity groups, MSU AgBioResearch, MSU Extension and the Michigan Department of Agriculture and Rural Development.

Similar tractors can sell for $50,000. Srivastava said he’d like to keep the tractor under $30,000 to help make it accessible to small farms as well.

Srivastava said the next step is to update the current batteries with ones that are more efficient and weigh less, like lithium iron phosphate batteries. He also noted that he’s researching ways to make the tractor autonomous. 

Next steps being taken toward new MSU dairy farm 

Design has begun for the new MSU dairy farm. 

Last year, Michigan State University received $53 million in state funding to renovate the university’s dairy and greenhouse facilities. From that amount, $30 million will be used toward the construction of a new on-campus dairy farm.

Currently, the dairy farm milks 210 cows in facilities that were built during the 1960s. With this funding, MSU will be able to create space for and house 680 mature cows. 

Other updates to the new facility will help modernize milking, cooling, lighting and wiring systems. Bradford said the facility will eliminate hand-feeding of research cows, transitioning toward a more autonomous approach. 

The facility is estimated to be completed and cows are projected to be moved in by 2026. 

The MSU dairy farm has been nationally recognized for its milk quality. It also provides students opportunities to learn about the dairy industry through its dairy management program. 

Bradford said the climate conditions of Michigan are well suited to high-quality forage production and cow comfort. Coupled with the MSU research efforts on environmentally sensitive dairy practices, Michigan’s dairy industry has a chance to grow by 50% in the coming decades.