Model manure user
April 28, 2008 by Diane Mettler
Minnesota’s Haubenschild dairy
farm is a model of both a successful dairy and a renewable energy
source, with its manure digester system.
Minnesota’s Haubenschild dairy farm is a model of both a successful dairy and a renewable energy source, with its manure digester system.
From an early age, Dennis Haubenschild had an interest in anaerobic digesters. He studied them in college, learned about their capabilities and even their history dating back to pre-World War II. So it was fitting that the Haubenschild farm, near Princeton, Minnesota would apply and be selected as a pilot site for a heated plug-flow anaerobic digester.
|Electricity created by the biogas, through the engine/generator, meets the needs of the Haubenschild Farm. And the energy is reliable, with a
reliability rate of 98.6 percent.
The 1,100-acre Haubenschild farm is a family-run operation. “My dad bought the land in 1952,” says Dennis. “We started with two cows, and now we’re milking about 850 cows and the crops are primarily corn and alfalfa.”
Although Dennis’s dad (now 80) still helps out, it’s Dennis’s sons, Thomas and Bryan, who are equal partners of the dairy, along with Dennis and his wife Marsha.
The county where the farm is located is known for its sandy soil. The previous owners of the Haubenschild farm had even given up trying to grow potatoes. “The soil here has less than a half percent organic matter. So in 1952, animal manure was basically the only way you could get crops to grow. And that stayed with me.”
And it was this continued interest in treating manure as an asset, as opposed to waste, that led him to apply to be an AgSTAR “Partner Farm.” AgSTAR—a joint program of the Environmental Protection Agency, the Department of Energy and the Department of Agriculture—selected 13 farms nationwide to demonstrate farm-scale anaerobic digestion technologies in an effort to promote the use of anaerobic digestion systems.
Once a farm was selected, a digester had to be installed that would meet the specific features of the farm, including being able to handle manure collected by scraping and also be able to handle high solids (10 percent).
“We met with Mark Moser from RCM,” explains Dennis, “and we looked at some of the designs and digesters. They met my criteria, and that’s what we went with.” Construction of the digester started in the summer of 1999 and was finished in the fall of that year.
The 350,000-gallon covered concrete tank has suspended heating pipes that heat the manure to between 95 to 105 degrees. The bacteria inside the digester break down the manure, creating methane.
“In September 1999, the Cat 3406 engine-generator was running on biogas, producing about 120 kilowatts of electricity and supplying the farm,” says Dennis.
The overall manure handling became and still remains a twice-daily routine. Approximately 20,000 gallons of manure is scraped daily from the two free stall barns into a collection pit. There it’s stirred periodically during the day and then a Flygt 17 horsepower electric pump pumps it into the digester.
A unique feature to the Haubenschild operation is its bedding—newspaper. They pick up the paper at their local recycler and use approximately one ton a day. It is easily digestible and increases the amount of methane gas.
|Dennis Haubenschild (left): “Consistency is the key to a successful operation. We’re feeding the digester morning and night. We treat the digester like another animal.”|
“Consistency is the key to a successful operation,” says Dennis. “And we’re feeding the digester morning and night. We treat the digester like another animal. It’s a living thing.”
It takes approximately 21 days for the manure to work its way through the digester and then it is gravity fed to a 3.2 million-gallon earthen basin with plastic liner. The material is stored there until Dennis is ready to apply it to the fields for the crops. The digestate that comes out of the digester is about six percent solids (30-15-30 N-P-K), and is shallow incorporated with tanks. They use three tanks: a 7,200-gallon Houle, a 5,000-gallon Van Dale and a 4,000-gallon Van Dale.
As it happens, their nutrient management plan calls for 6,000 gallons per acre, giving them the necessary amount for a year’s crops. The manure is high quality and the farm is now solely organic fertilizer with the exception of a small amount of starter.
The benefits of the digester have been many. One advantage has been the elimination of 90 percent of the odors. “The farm is located in a bedroom community and if we were going to spread before, we would do it on a Wednesday because then it would have a day or two to cool off a bit, and air out for the weekend. It’s not a benefit you can take to the bank. But if it eliminates a lawsuit, it’s worth it.”
The Haubenschild have also experienced a reduction in pathogens and less weed seeds in the treated manure that’s been injected.
The big advantage, though, is that the manure is a source of renewable energy. The heat generated from the digester is used to heat the milking parlor, holding pen, breezeway and tanker bay and keeps the floors free of ice in the winter, saving the farm $4,000 in propane costs.
The electricity created by the biogas, through the engine/generator, meets the farm’s electrical needs. And the energy is reliable. During six years of operation, Haubenschild Farms had a reliability rate of 98.6 percent.
And the excess energy can be sold. For the first five years, the Haubenschilds sold the excess kilowatts to the local co-op. “We had a five-year contract. We were selling about $2,500 per month worth of electricity. The co-op turned around and sold the electricity as renewable power—CowPower—and customers paid a little extra.”
Dennis is a big proponent of generating renewable power and feels that utilities are going to have to join in on that, and join in soon. “When I go around speaking, I talk to these utilities and they know that they will have to go to renewable energy sooner or later.” And Dennis is working hard to ensure that the agriculture industry is ready when that day comes.
Dennis spends most of his time running the back end of the barn (the research) while his sons run the front end (the daily operations). “If it wasn’t for my sons, I couldn’t do this work. The experimental side is very time consuming. The digester, though, doesn’t take any more time than it takes to handle your daily manure,” he says. “In fact, we probably spend less time handling manure now because we do it as a bi-daily chore instead of once a week. It’s no more different than feeding the calves twice day.”
Besides continuing to do his research, Dennis plans to keep taking his message all over the US—speaking to dairymen and engineers and at renewable energy conferences.
“Manure is too valuable to waste. That’s one of the things we’re trying to eliminate in the term ‘animal waste’.” It’s a byproduct, a non-depleting renewable resource, he explains.
Dennis even got a chance a couple years ago to sit down with Vice President Dick Cheney and a half dozen other farmers to discuss the energy aspects of manure.
“The Bush Administration wants hydrogen to be part of the cure to the energy crisis. And it’s made it that much more important to me that agriculture should be part of that,” Dennis says.
“I seriously believe agriculture can provide not only food, but we can also provide part of the energy and that’s why I’m now working converting some of this biogas into hydrogen and doing research on hydrogen with the University of Minnesota, to show it can be done,” Dennis adds. “If we [the industry] can be at the ground floor of the hydrogen technology, we can be a part of the answer and be at the forefront.”
Dennis will admit wholeheartedly that it isn’t an easy challenge and one that will take state and federal action. “To make it work, we’re going to either have national renewable energy portfolios or good state renewable energy policies. Right now, I’m in the process of working with a company for verification credits for burning methane. It’s going to take these types of things to make it work.”
Dennis finds that although there is interest in digesters and renewable
energy, many farm operations are waiting to see how things pan out before making the investment. He’s continually asked by dairymen, “How can you make it pay for itself?”
“That’s the challenge,” says Dennis. “We’re never going to be as efficient as coal, for example. So we can never compete head on with the electric utilities. We’re producing energy in 21 days and they are using energy that was created 21 million years ago.
“The only way we’re going to be able to compete—and I hate to use the word compete, but that’s really what it is—is through mandates. They are not going to let us willingly onto the grid without being mandated by renewable energy mandates or something similar.”
|The Cat 3406 engine/generator which, running on biogas, produces about 120 kilowatts of electricity and supplies the farm.|
One such state where mandates seem to be working is Wisconsin. There, the utility companies have been directed to produce a certain number of kilowatts of electricity of renewable energy. “The utilities in Wisconsin are actually building digesters because they know that’s the most reliable source of renewable energy available,” says Dennis.
“I really feel it’s a no-brainer for agriculture to be part of this. And if we at our farm can do it using the KISS (Keep It Simple Stupid) method, then whatever I do on this dairy could be done on any other dairy. That’s one of our goals.
“We are just using another one of Mother Nature’s tools. It’s not the easiest tool to use; it’s another living thing. You’re not going to spend half a million to a million dollars and then just think you are going to turn a switch on and it’s going to work. It’s got to go through a maturing process and it takes a while for it to happen. But it will work.”
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