Need For Renewable Energy Brings Business to Sauk City

By Donna Stehling Special to Agri-View
Sunday, December 28, 2008 9:06 PM CST

Michel Zander knew cows give milk. “That’s all,” he says. “I have no farm background.” He’d been a software engineer for RWE, a large power company in Germany when renewable energy was not an issue.

Today, renewable energy is a global issue and Zander, now CEO of his own American company n Energies Direct LLC of Sauk City n makes custom manure digesters, large concrete containers with a double membrane roof, the inner membrane expanding to store up to 10 hours of methane. And the German company that employed him now has a renewable energy division, while Germany n a country about the size of Wisconsin and Minnesota combined n is not only the world’s leader in solar energy, it has 4,000 digesters.

“The smallest is for 40 cows,” Zander says. With all the cows he saw in Wisconsin, Zander kept wondering why there weren’t more manure digesters here. “Digesters can handle anything organic, like a big stomach, just like a cow. It’s no secret,” he says.

He explains that digesters need the proper temperature to get bacteria to work and the organics must be mixed to get the methane gas out. “I did my first digester in Fond du Lac for Gary Boyd, just for fun,” he says. “But I learned from Boyd. He told me I had to have a business plan and gave me the name of a friend of his, a consultant n Paul Soglin.”

As Soglin helped with the business plan, the former mayor of Madison became more interested in the business. “Now he’s part of the system,” says Zander. Soglin is the chief operating officer for Energies Direct.

Soglin and Zander are interested in Dane County’s effort to clean up the Madison area lakes by linking farms together to get the manure off the fields in an economical way. It’s about reducing the impacts of nitrogen and phosphorus to groundwater while also producing energy and having fertilizer for the fields.

The community manure feasibility study has three goals: to allow the livestock industry to continue to survive in Dane County; to protect water quality; and to protect open space. A link on the Dane County Office of Lakes and Watersheds Web site opens numerous committee documents about the manure management feasibility study.

“This is really exciting,” says Zander. Not only can five cows produce enough energy to power one household for 24 hours, but for farmers and their neighbors, “the smell is gone and most of the flies go away. You can put the manure on the fields after processing and there is no odor.”

Zander says he started building digesters because of the smell. Research documents list reducing odor levels by 90 percent as a benefit and advantage.

But there is more. Soglin says the fertilizer quality does not go down with processing. In fact, during the anaerobic digestion, organic nitrogen in the manure is largely converted to ammonium, making it more accessible to plants and reducing the need for chemical fertilizers. Furthermore, the process removes phosphorus and destroys a number of microbial pathogens while converting weeds, leaves, grass clippings, paper, chipped yard wastes and food wastes from restaurants and markets to energy which, after processing, can be dried and used as either fertilizer or barn bedding, a useful or marketable product.

“The bedding needs to be changed more often than sand,” Zander says, “but it goes right back into the digester. There’s no waste. The digester also destroys weed seeds, reducing the need for herbicides.”

Zander compares the digester to a cow’s stomach; Soglin likens it to a compost pile. Scientifically, an anaerobic digester composts organic waste in an oxygen-restricted environment where microbes produce methane and carbon dioxide. The digester gas, contaminated with hydrogen sulfide, is burned as fuel to make electricity. Digester gas can also fuel equipment or be used to produce heat.

Digesters can be designed for sewer sludge at wastewater treatment facilities in urban areas or for animal wastes on farms. Meanwhile, research continues to determine whether digester technology on a variety of scales, will control emissions, be efficient and can be a sustainable way to handle waste in the United States.

Zander and Soglin want to continue improving their product and service. “I have 150 engineers behind us,” Zander says. “We’re putting together all resources needed, seeking the best professionals for safety, efficiency and engineering.”

During a recent trip to Germany, Zander says, they learned about “dachs” (badgers) n small engines that produce energy (BTUs) for houses in Germany. “It’s a big deal there,” Zander says. “The engine will be part of the digester.”

It’s the way to take heat from the digester to heat a home, a hospital or a school.

“Digesters must be economically manageable,” Soglin says. “We can now produce income from electricity, fuel for machinery and have fertilizer for field application. We can avoid groundwater contamination because of the quality fertilizer or move it to other areas with soil deficiency.”

Interest in anaerobic digesters is growing with the number of digesters in this country doubling over the last five years. In some states there are tax incentives for both construction and biomass usage to produce energy.

As is done successfully in Denmark, in Dane County they are now looking at ways for clusters of small farms to pipe manure to a central digester while communities like Mexico City are investigating how to finance a digester to process the green market waste to produce energy. In Germany, people have green trash cans where they put all their organics, including grass and leaves, to be hauled off to their existing community digesters. Digesters are part of community life in European communities.

“There’s much power in grass and leaves,” Zander says. “In Dane County,” Soglin says, “we hope to meet with the Streets Division and the accountants.”

Soglin says the street department and waste haulers estimate they handle 17 to 20 tons of leaves and grass, five tons of yard waste, two tons of weeds from the lakes, and need two to three tons of food wastes from restaurants to make a community digester a viable operation. There can be covered lagoon digesters, complete mix digesters, or plug-flow digesters, all of which trap methane and reduce contamination of groundwater with fecal coliform bacteria. In addition, these digesters would produce fertilizer people could utilize on their fields or gardens.

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