Cultivating the Power of Nature's Call

The manure management side of farming is far less smelly and far more profitable when the animal waste is converted into a power source. Such a biomass process is up and running at farms across the United States. Although the basic technology isn't new, it's generating attention for a Wisconsin company, GHD Inc.

CHILTON, Wisc. — The manure management side of farming is far less smelly and far more profitable when the animal waste is converted into a power source.

Such a biomass process is up and running at farms across Wisconsin and other states. Although the basic technology isn't new, it's generating attention for a local company, GHD Inc.

Company owner Steve Dvorak has run a farm implement dealership for 27 years. The farm boy turned engineer kept hearing farmers complain about manure management, and ended up developing his own line of anaerobic digesters, or waste-to-energy processors, in a complex system born of the simplicity of nature's call.

His business, with 11 employees, sells such systems around the state, across the country and now overseas.

In an anaerobic digester, cow manure is funneled in 24-inch underground pipes to long underground caverns, about the length of a football field.

A generator is used to heat the manure to 100 degrees; the reaction from the heated manure, in turn, helps run both the generator and power other parts of the farm. Unneeded power is sold to the broader electric grid.

What's left: Lagoons of wet manure, minus the toxins -- and suspended solids, an odorless remnant of cow dung that is used for cow bedding.

Dairy farmer Kenn Buelow runs a 3,700-cow, 30-employee dairy, Holsum Dairies, in Hilbert just outside Chilton. His GHD system, while costly, allows his large farm to operate in an area where other farmers routinely receive complaints about flies and foul odors.

Savings every month

Cost savings come every month, thanks to the power he's selling to Green Bay-based utility Wisconsin Public Service Corp, and from the heat his system provides his barns, milking parlor and office. Other savings: He no longer has to buy commercial fertilizer for his farm fields, and he can spread the liquid manure all summer long rather than waiting until fall.

"Plus there's the $10,000 a month we don't have to spend on bedding," he said.

His cows are so prolific, that the bedding byproduct is now being sold to 11 farmers, one as far away as Antigo, Buelow said.

Anaerobic digesters have been around for decades, but they're getting more attention as utilities look to whet customer's appetite for energy from renewable resources.

From a purely economic standpoint, the technology is not competitive with power purchased from a utility. Dvorak says his system is cost-effective for herds of at least 400 to 500 cows, at least with current technology.

Bill Johnson of Alliant Energy Corp. of Madison compares the status of digesters today to where wind turbines were at more than a decade ago. Since then, wind power has gotten more competitive, through better technology, longer blades, taller towers and higher costs of other forms of generating electricity.

Long term, the potential for wider application is great, says Johnson, manager of agricultural compliance for Alliant's utility, Wisconsin Power & Light Co.

After all, even the best sites for wind turbines can't generate electricity all the time because the wind isn't always blowing, he said. Cows are always eating, digesting and creating waste.

"Anyone who's ever worked behind a cow will know that this is a renewable resource that's there all the time," he said.

Many advantages

But Johnson said there are many other advantages to having a digester -- environmental and economic.

It helps combat fly problems, it's sustainable, and it could soon play a role in preserving the family farm.

In the next year or two, he predicted, smaller scale systems will become more economical, permitting farmers whose herds are fewer than 500 cows to take another look at digester projects they've written off as too costly in the past, Johnson predicted.

"That will be important because of urban encroachment," he said. "People want the rural life, but they don't want to smell it. There's going to be more and more pressure on dairy agriculture."

Anywhere farmers are

Dvorak sees a market for the systems wherever farmers are located. That took him to northern Illinois last month and is taking him to Georgia this week to oversee installation of a system.

Another system is being installed in Siberia, and the company sees customer interest from Canada and Mexico as well, Dvorak said.

"Kenn was one of the first ones to do it," Dvorak said of Buelow. "But it's starting to come." Buelow's digester was one of the first built by GHD.

Today, seven farms with 15,000 cows are making energy from manure using GHD technology, the company said. That includes several in Wisconsin and others in Vermont, Washington and Indiana.

In addition, the U.S. Department of Agriculture has awarded rural business development renewable energy grants in the last two years based on GHD technology to 31 farmers, including 21 in Wisconsin.

The growth of manure power is being watched in Madison, where a renewable energy task force appointed by Gov. Jim Doyle recommended that the Legislature encourage development of more anaerobic digesters across Wisconsin.

The task force said it sees waste-to-energy systems, also known as biomass, as playing a role in helping Wisconsin meet the goal of having 10 percent of its electricity generated from renewable sources by 2015.

"As electricity prices continue to rise and the costs of renewable energy systems fall, a growing number of Wisconsin's large farms are implementing anaerobic digestion -- manure-to-energy renewable energy systems -- to reduce their utility bills and improve the environmental performance on the farm," said Don Wichert, director for Focus on Energy's renewable energy program.

Focus on Energy, which gave Holsum a $55,000 grant to help with the GHD system, estimates that his system generates 1.6 million kilowatt hours of electricity and more than 109,000 therms of energy a year, enough to keep 2,500 tons of carbon dioxide from being released in to the atmosphere.

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Source: Knight Ridder/Tribune Business News