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Portland will convert methane into natural gas at The Columbia Boulevard Wastewater Treatment Plant, a part of a collection and treatment system that serves more than 614,000 residential and commercial customers. The plant operates every day around the clock to manage, monitor and adjust the treatment process. Sewage pump stations and pipes convey wastewater to the facility 24 hours a day.

(Thomas Boyd/The Oregonian)

Portland plans to make money off of its sewers' fumes in a project expected to lower the city government's carbon footprint by one third by converting a noxious gas into energy.

The Portland City Council unanimously approved on Wednesday the construction of a $9 million facility to convert methane gas in the city's sewer system into marketable natural gas. City officials plan to sell that natural gas through a Portland-based natural gas distributer to governments and organizations looking to replace diesel fuel in cars, buses, garbage trucks and other fleets of vehicles.

"We're going to be turning poop into power," Commissioner Nick Fish said. Fish manages the Bureau of Environmental Services, which oversees the project.

Contractors will build the facility at the Columbia Boulevard Wastewater Treatment Plant, which already uses much of its methane to generate electricity and heat. Together, Portland's solid waste treatment plants use 77 percent of the sewer system's methane to generate energy, bureau director Mike Jordan said.

But the two plants can't use the remaining 23 percent of the methane. Instead, they burn it, which emits carbon dioxide into the environment.

The new treatment facility will enable the city to convert that remaining methane into natural gas, thus creating a renewable energy source that can be used as a substitute for diesel fuel.

The new project is expected to significantly reduce the city's carbon footprint, said Bureau of Planning and Sustainability Director Susan Anderson.

"From an environmental point of view, it's not just about our local air quality," Anderson said. "It's about reducing carbon emissions. We need to walk our talk."

The city plans to sell the product for credits they will be awarded based on the volume of natural gas they sell to oil companies and other "obligated parties" required to invest in renewable energy or purchase carbon offsets under The Clean Air Act, said Paul Suto, supervising engineer at Portland's environmental services bureau.

The environmental services bureau's natural gas production is expected to bring in $3 million to $10 million of revenue per year, depending on the value of the credits in state and federal energy markets, bureau officials estimated.

The city could sell its credits through California's Low Credit Fuel Standard program, Suto said. Oregon has a similar program called The Clean Fuels Program.

Portland is negotiating a contract with Midwest energy assessment company Clean Energy Renewables to help make its plan work. The firm will find potential buyers, value the volume of natural gas and ultimately help monetize the city's energy credits, Suto said.

Suto said the city hopes the renewables firm will help the environmental services bureau tap into local markets. Their product could potentially replace diesel fuel in city fleets, buses and even TriMet, should the transit agency decide to shift away from biodiesel.

Bureau officials estimated they could replace enough diesel fuel to power 154 garbage trucks per year.

On Wednesday, the council also unanimously approved a $1.9 million contract with a Portland-based natural gas company, Northwest Natural, to install and operate a station to fuel vehicles with compressed natural gas. Commissioners also approved a $1 million contract for Northwest Natural to transport natural gas to buyers.

The unanimous votes move forward a project that Commissioner Dan Saltzman started exploring when he ran the environmental services bureau in 2008.

"I'm truly proud that today we are taking the steps to capture all that methane and put it to good use," Saltzman said.

--Jessica Floum

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