Producing renewable natural gas from manure could change future of power

Grace Connatser
Wisconsin State Farmer
A new anaerobic digester owned by DTE and located on property its leases from Rosendale Dairy will collect biogas from breaking down the manure from the farm's herd of 9000 cows which will be processed into renewable natural gas.

As farmers continue to innovate in environmental sustainability and find greener alternatives to traditional energy sources, manure digesters are becoming an increasingly important way to convert waste into reusable power.

Anaerobic digesters separate manure's solid and liquid components and harvest the methane to be used for electricity and power especially in transportation. The methane is processed and cleaned of impurities to become almost pure methane and then distributed to the electric grid or other non-utilities buyers. The solids can be reused as bedding for the cows that produced the manure in the first place.

A Hoard's Dairyman webinar series on sustainability explored the possibilities and challenges within the manure digestion industry Aug. 19, with several industry experts as panelists. The panel included Mark Stoermann, COO of Newtrient; Danielle Goodrich Gingras, owner of Goodrich Family Farm; Richard Cooper, director of business development at DTE Power & Industrial; and Mark Stephenson, dairy policy expert at UW-Madison.

Stephenson said 230 of the total 330 digesters in the United States are located on dairy farms. Of those, 100 manure digesters are generating 25 million cubic feet of biogas per day from 200,000 dairy cows. Despite those big numbers, Stephenson said there's still a lot more room for potential.

Dr. Mark Stephenson

"If all of that gas manages the pipeline, it would be enough to supply about 150,000 homes with all their natural gas needs," Stephenson said. "There's room for a lot more digesters, there's a lot more opportunity to think about this biogas in the pipeline. ... It is a methane mitigation tool at one level, and it is an energy source at another."

Stoermann said capturing methane to be reused as electricity reduces dairy's climate impact by reducing the amount of methane in the atmosphere, and it can also be used to replace traditional fossil fuels like oil. As the concept becomes better known, states like California and Oregon are already offering incentives to farmers and utilities who capture and distribute the methane for reuse in transportation markets. These states have their own renewable fuels standards programs, but there's also a federal program that offers funding to begin building these projects.

Creating renewable natural gas through methane capture adds values of up to 30 times the current selling price of natural gas, Stoermann said, making it a booming market. However, getting into the market as a dairy farmer is expensive to do on your own – not only are dairy farmers pressed for cash, but they're also pressed for time to run a digester project along with their regular dairy and crop production, he said.

Mark Stoermann

"I'd like to say that it's easy for everyone to get into this project, and it's easy to get these projects going. That's just not the case," Stoermann said. "You get a lot of costs that right now really needs 5,000 to 10,000 pounds in one location to justify getting a project going. More and more of these projects are looking at distributed systems where we're gathering gas and bringing it together."

One alternative, Stoermann said, is to go in on a project with multiple farmer partners and split the profits. While you don't get all the rewards, you do mitigate a lot of the risk, especially when you partner with someone who already has the financial security and contracts to get it done. However, he warned that you should be careful to enter into these projects only with people you're comfortable and communicative with.

Cooper said many investment firms are also on the hunt for investing in these projects just as they already trade environmental commodities and electricity. He said his company began investing in methane capture in the 1990s through landfills, which would produce methane from rotting garbage in the absence of oxygen. He said it's even better to accomplish the same thing through manure digesters because it's helping out dairy farmers.

"We're long term investors in the space. ... There's no exit strategy," Cooper said. "And we want to align with the farmers. We understand what the farmers involved here need to run their business and we try to just not get in the way and add as much value in areas where we think we can add value."

All of DTE Power & Industrial's manure digester sites are located in Wisconsin, and the company is currently building what will be their biggest site near Sioux Falls, S.D. Cooper echoed that these are not only renewable natural gas projects, but they're also "methane mitigation" projects that ultimately help the environment reduce greenhouse gases.

Goodrich Gingas, whose farm is part of a methane capture project, said she has no regrets about joining the project, even though she sometimes struggled to comprehend the logistics of such a project.

"It went over my head so fast," Goodrich Gingas said. "It was a little bit overwhelming, but it made me extremely grateful and lucky that my partners project was to continue to do what I did best, and that was take care of my cows and just make sure that I was continuing to provide manure for the project. For me, that was good enough."

The manure digester allows her to also collect comfortable bedding for her cows that is readily available on-site, rather than wait for sawdust to be delivered to the farm. She said the operation saves $50,000 on bedding alone annually. The project has also allowed them to move away from commercial fertilizer, another big savings for the farm, and switch to low-carbon fertilizer instead that is easier to spread. Plus, she said they have also installed a phosphorus removal system that helps keep their watershed region clean and community healthy.

The Goodrich Family Farm manure digester produces 80,000 tons of low-carbon gas per year, Goodrich Gingas said. She explained that even though the project took a long time and a lot of work to come together, it's ultimately benefited her family and community, and she is still able to focus on taking care of the cows and the family.

"Working with someone that understood us that well and was also willing to get his boots a little dirty, we knew that we were working with the right people," Goodrich Gingas said. "When all of us worked together, we accomplished something that none of us individually could have done. It's expensive. ... We realized that we all were trying to accomplish something bigger than just ourselves."