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The Lure of Manure
Dairy farms in both Minnesota and Wisconsin are picking up on a technology that is moving out of the labs and onto the land: anaerobic digesters that turn animal manure into electricity and cash for farmers.
Essentially, farmers load their cow manure into large, sealed tanks on their property. Bacteria in these tanks break down the manure and separate it into biogas (which is mostly methane) and solid and liquid waste. The biogas can be piped to a generator to create electricity and heat or to a boiler to produce just heat. The remaining waste can be used as soil fertilizer for crops or as animal bedding for the cows. And without the methane, the reused manure doesn’t have that distinctly, how should I say, unique smell.
The electricity produced from the biogas can be used on the farm or sold to local power distributors. After installing digesters in 2008 and 2010 at three farms in Stevens County, Minnesota’s largest dairy company, Riverview, sells the electricity it produces to Great River Energy. Riverview’s digesters produce about 3.6 megawatts, or enough electricity to power about 2,740 average American households.
This partnership also greatly benefits Great River Energy who, thanks to Minnesota’s Renewable Energy Standards (RES), is required to produce 25% of the electricity it distributes from renewable sources by the year 2025.
So why does this process that provides a renewable energy source, prevents a highly potent greenhouse gas (methane) from entering the atmosphere, reduces farming costs and puts cash into farmers’ pockets, and helps utilities meet their RES requirements not implemented on every farm in the state?
As with most emerging technologies and renewable energy sources, the answer is economic. Despite the financial benefits the digesters bring, the cost for getting a digester up and running can be $1,000 or more per cow depending on the size of the farm. While larger dairy operators like Riverview may be able to afford this investment, smaller farmers may have difficulty coming up with the cash.
But this technology is not going away and may even expand into other industries. Research is being distributed to food companies in Minnesota that highlights the possibilities of using food processing waste to feed anaerobic digesters. The University of Minnesota-Crookston recently released the Northwest Minnesota Methane Digester Feedstock Inventory, which lists potential digester feedstock sources. And large companies like American Crystal Sugar in Moorhead, MN have already experimented with the process for their own waste products.
Leadership at the state level, in ways highlighted in this recent Brookings Institute report, will be critical in facilitating the uptake of anaerobic digesters throughout Minnesota. Vermont has taken a positive step towards assisting its farmers and citizens on this issue, Minnesota can do the same.
Posted in Economic Development | Related Topics: Agriculture Energy Climate Change Sustainability
2 Comments
January 19, 2012 at 12:23 pm
In 1996 we worked with the Legislature, Minn. Dept. Of Ag, and the Assoc. of Minn. Counties to successfully create funding for a revolving loan fund to jump start Methane Digester installations.
With help from MPCA and MDA a project developed near Cambridge, Mn. and I believe is still in operation today.
This technology is not new as it has been used in Europe and Asia for many years.
In 1996 several County Commissioners from across the United States were in Washington D.C. for a National Assoc. of Counties Legislative Conference. Our Agriculture Steering Committee had the opportunity to tour a dairy operation in Pennsylvania and saw and experienced that yes, you can digest manure, create electricity, reduce the odors, and have a final byproduct that can be used as a fertilizer with no odor.
I applaud your efforts and urge you not to take no for an answer.
Tim Bonham says:
January 19, 2012 at 10:33 pm
Last Fall, I represented the Minnesota Horse Council at a national meeting of the various State Horse Councils. One of the presentations was about these digesters.
Frankly, they didn’t seem very useful for a normal-sized horse operation. They are big, expensive, complicated, and require a constant large supply of manure. A much simpler (and cheaper) compost site seems more feasible for a horse farm.
The comparison seemed to be that these were like a municipal sewage operation, while a compost site seemed to be like household septic system.
Perhaps these digestors would be suitable for a big corporate farm, with thousands of animals. But the average small farm would be better served with a simple compost site. And that is something cheap enough, and easy enough to operate, to actually be used by a small farm. Our state woould be better off if we encouraged farmers to start out with something small & reasonable, rather than pushing new, expensive technology at them.