Iowa Projects
Installing methane recovery technology is site-specific and dependent upon factors such as the type of livestock or amount of landfill waste, waste management methods and permitting requirements. Here is a description of the major methane energy recovery projects operating in Iowa.
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Methane Recovery at Livestock Operations: Top Deck Dairy, Inc., Westgate, Iowa
Located near Westgate, Iowa’s first cow-manure methane recovery system is turning waste into electricity in northeast Iowa. Top Deck Dairy, Inc. is owned by Judy and Roger Decker, along with their sons, Derek, Jason and Justin. When the Decker family expanded its operation from 300 to 700 cows, they researched the potential of installing an anaerobic digester for electricity production.
The Department of Natural Resources provided a $157,900 grant to build the digester, while Alliant Energy supplied $250,000 for the generators and to connect the system to the utility grid. Top Deck Dairy funded the remaining costs of the $502,000 facility.
Construction of the system began in the fall of 2000. Dan Meyer, Iowa State University Extension engineer, coordinated construction of the project, and electricity production began in May 2002. The Deckers installed a system called a plug-flow digester that treats the manure. About 17,000 gallons of manure each day is scraped to the digester, where it decomposes and subsequently produces methane gas.
The captured methane gas is sent through a connecting pipe to a 150-horsepower engine with a 100kW generator and a 30kW microturbine, which are owned by Alliant Energy. The generators create 864,000 kWh of electricity annually, enough to meet the energy needs of 100 homes. Heat from the engine and micro turbine are also captured and used to preheat the manure, improving the anaerobic process. Hot water from a heat exchanger provides floor heat to the parlor area, where the cows are housed.
Top Deck Dairy Final Report,*.pdf file
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Methane Recovery at Landfills
Landfills can provide a valuable source of renewable energy. As organic materials deposited in a landfill decompose, landfill gas (LFG) is produced. LFG can be burned to produce electricity, heat, fuel, or used in industrial processes. In the United States, more than 325 landfills collect LFG. Iowa has three landfill gas-to energy projects:
- Blue Stem Solid Waste Agency Landfill, Cedar Rapids, collects 1.9 million cubic feet of landfill gas daily. Prairie Creek Power Station uses the gas to produce electricity, with generation capacity of 4.5 MW.
- Metro Waste Authority, Mitchellville has collected LFG since 1993. The facility is operated by Waste Management of Iowa and the Metro Waste Authority, with electricity sold to MidAmerican Energy. The captured methane fuels eight generators, each with a capacity of 800 kW. The facility has reached its design capacity of 6.4 MW.
- The Scott County Landfill, Davenport, is located at a quarry where methane provides fuel to heat a kiln. The landfill can produce1,000 cubic feet of biogas per day for that purpose.
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Methane Recovery at Waste Water Treatment Plants
At least 19 Iowa municipal wastewater treatment plants capture methane for on-site use and electricity generation, collecting more than 1.2 million cubic feet of biogas per day, enough energy to heat 2,555 homes annually. More than 250,000 tons of municipal treated sludge could be available each year for anaerobic digestion in Iowa with the potential to produce 3 trillion BTU, the equivalent to the power and heat consumed by 23,700 homes annually.
DNR Contact:
Jim Bodensteiner
(515) 281-8416
Jim.Bodensteiner@dnr.state.ia.us
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