Agency to turn methane gas from landfill into electricity and heat

Linn County landfill generator will produce electricity to support about 1,000 homes

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March 31, 2014 | 11:19 pm

CEDAR RAPIDS — The Cedar Rapids/Linn County Solid Waste Agency is at it again, preparing to turn methane generated by decaying landfill trash into electricity and heat.

The latest agency effort is taking place at its Site 2 landfill, at County Home Road and Highway 13 north of Marion, where the agency currently has a well and pipe system to capture methane that it burns off into the air with a flare system.

By January, the agency plans to use the methane to drive a generator to produce electricity and feed it into the rural electrical grid.

Brian Harthun, the agency’s consulting engineer, on Tuesday said the agency hopes to recoup from the sale of electricity the $3 million in upfront capital costs for the new waste gas-to-energy system. It should take about 10 years, he said. After that, the production of electricity will become a revenue source for that agency, he added.

The agency’s generator will produce about 1,600 kilowatts of electricity an hour, an amount sufficient to provide electricity to about 1,000 homes, Harthun estimated.

The setup, he added, will allow the agency to capture heat from the generator, which will used to heat the Solid Waste Agency’s new Resource Recovery Center building, now under construction. The heat will save the agency an estimated $90,000 a year in propane heating costs, Harthun said.

Karmin McShane, the agency’s director, on Tuesday said the energy production from methane is a bonus for a methane collection system designed firstly to manage the landfill’s methane gas and to cut down on its odor. The system at Site 2 now features 22 vertical wells and seven horizontal wells that feed methane to a central collection point, Harthun said.

The agency’s history with converting landfill methane into a resource reaches back to 1984, when the agency built a collection system at its Site 1 landfill near Czech Village to pipe methane to Alliant Energy’s nearby coal-fired power plant, McShane noted on Tuesday.

The system was damaged in the flood of 2008, and since 2009, the Solid Waste Agency and the contractor that managed the system have been mired in a lawsuit. The legal matter is slated for arbitration in October, McShane said.

For now, she said the methane collected at Site 1 is burned off with a flare with no end user for the gas connected to the system.

Flaring the gas is better from a greenhouse-gas standpoint that allowing methane gas to seep into the air, agency spokesman Joe Horaney added on Tuesday.

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