City signs contract to turn sewage gas into electricity

October 24, 2006|By Timothy B. Wheeler | Timothy B. Wheeler,Sun reporter

Baltimore has signed a $14 million contract with a Milwaukee-based company to generate electricity from the methane produced by the city's Back River sewage treatment plant - a project officials say they expect to save the city $1.4 million a year in energy costs while also improving air quality.

The contract with Johnson Controls Inc., to be announced today, calls for construction of a "cogeneration" facility at the city-owned plant near Essex, which treats the sewage of 1.3 million city and Baltimore County residents. The company also will upgrade lighting and install other energy-saving systems at the plant, which should save an additional $400,000 a year, city officials say.

"The city wants to reduce energy costs - whether by consuming less energy or producing it more efficiently," Public Works Director George L. Winfield said in a statement. "This project does both."

The city spends about $5 million a year to operate Back River, which daily treats 180 million gallons of wastewater, according to Hatim Jabaji, chief of energy conservation for the city Department of Public Works. For years, city officials have been heating the plant buildings with some of the methane produced in the treatment process, as bacteria "digest" the waste filtered from the water. The bulk of the flammable gas, however, was burned off in 20-foot-high, open-air flares.

"Just seeing the flares, to be honest with you, we always looked at that as wasted energy and wanted to do something with it beneficial," Jabaji said in a recent telephone interview.

City officials say they expect the energy savings from the project, which is scheduled to be completed in 18 months, to pay for itself within a decade. They say it also will reduce air pollution - curtailing emissions of harmful carbon monoxide and nitrogen oxide.

A Johnson Controls spokeswoman said the Back River project is the only cogeneration plant it is building at a sewage plant, though it has two others under design. The company, originally known for producing thermostats, now manufacturers automotive interiors as well as energy-saving products and services. It also produces batteries for automobiles and hybrid electric vehicles.

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