Wild Rose Dairy
|Project Type||Farm Scale|
|Population Feeding Digester||880|
|Baseline System||Storage Tank or Pond or Pit|
|Digester Type||Complete Mix|
|Co-Digestion||Food wastes (grease and fats from local restaurants)|
|Generating Capacity||775 kW|
|Receiving Utility||Dairyland Power Cooperative|
Farm Bill Funded Project
Wild Rose Dairy's owner acquired the benefits of anaerobic digestion through an agreement with Microgy, Inc. and Dairyland Power Cooperative. Microgy provided a complete turnkey digester, including development, construction, financing, and ongoing operation and maintenance. With Microgy providing financing, Wild Rose Dairy did not have a large cash outlay. Dairyland Power buys the resulting biogas and owns/operates the engine-generator set to generate electricity. Wild Rose Dairy pays off the debt on the digester through biogas sales to Dairyland. Dairyland Power owns the renewable energy attributes from the electricity generation.
The above ground carbon steel tank complete-mix digester with a fixed cover has been operational since 2005 and runs at a target temperature of 125°F. Manure, along with kiln-dried sawdust from bedding, is scraped three times per day from the barns. The system is designed to include co-digestion of off-farm high fat food wastes to boost biogas production. About 1,100 gallons of manure mixed with food wastes are batched into the digester hourly.
Solids are separated after digestion and are sold for use off the farm to other dairies for bedding and to organic farmers for fertilizer. The project includes the following benefits:
- Provides revenue from gas sales, which allows Wild Rose to pay down the debt on the digester
- Provides Dairyland Power Cooperative a competitively priced renewable energy source for their customers
- Generates additional biogas from added off-farm food wastes as an integral part of the business model
It is only right that the gas be put to use.
—Art Thelen, Wild Rose Dairy, quoted in Focus on Energy's Wisconsin Agricultural Biogas Casebook (July 2008 Edition)