Boxler Dairy Farm operates on 5,000 acres near Varysburg, New York in Cayuga County. The farm has the capacity to support 2,000 milking cows. As is the case with most dairy farms, manure had previously been collected and stored before eventually being field spread. Concerns about potential environmental damage led to Boxler Farm’s decision to install a plug flow digester, where the digester contents are conveyed by adding fresh waste and where an equal volume of treated effluent is simultaneously displaced. Manure at Boxler Farm is collected in a reception pit, mixed with silage leachate and food wastes, then loaded in the digester at regular intervals. Biogas produced as a byproduct of the anaerobic process is used to fuel a 500 kW engine-generator set. Heat recovered from the engine is used to produce hot water that serves multiple thermal loads at the site. Solids recovered from the effluent are dried and used for animal bedding. The remaining liquids are stored in a lagoon and eventually field spread.
Hourly data have been collected from the site since December 2009 and are available on NYSERDA’s DG/CHP web site. Capital costs for the system were approximately $2.7 million. Recent data indicate the CHP system has produced an average of about 9,000 kWh per day, or 3,285,000 kWh per year of electricity. The farm consistently exports electricity to the grid offsetting utility purchases through a net metering arrangement.
IFES Number: 58
Type of Firm: Farm
Main Products: Milk
Size of Firm: 5,000 acres; 2,000 milking cows
Ownership Type: private
Year Installed: 2009
Energy Feedstock: Cow manure; Silage leachate; Food wastes
Energy Produced: 3,285,000 kWh/year
Energy Uses: Digester heat, solids dryer, seasonal space heating
New co-products: bedding
TCO2 Eq Avoided: 4,731 metric tons CO2E/yr