Portland generating renewable natural gas

Renewable natural gas (RNG) projects are being developed throughout the country and Portland, Ore. is fueling its future with the announcement of the city’s first RNG-to-vehicle fueling station. On March 8, 2018, Portland City Commissioner Nick Fish and NW Natural representatives partnered to announce the opening of the station, which is located at the Columbia Boulevard wastewater treatment plant. The City’s natural gas vehicles were introduced that day as well.

NW Natural is the largest independent natural gas utility in the Pacific Northwest and provides natural gas service to about 750,000 residential, commercial, and industrial customers in Oregon and Southwest Washington.

The City dubbed the RNG project “Poop to Power,” because it was created to capture waste, clean it up, and then use it in heavy-duty trucks. The project was approved in April 2017 and will recover nearly 100% of the waste methane from sewage treatment, up from the current 77% recovery rate. That methane will be cleaned and used in two ways: in NW Natural’s pipeline and in City vehicles.

The project fits into NW Natural’s Low Carbon Pathway goals to achieve the following:

• Reduce the carbon intensity of its product by transitioning to RNG.
• Displace more carbon-intensive transportation fuels such as diesel with compressed natural gas (CNG).

“We’re proud to be a part of our City’s efforts to close the loop on waste,” said David H. Anderson, NW Natural president and CEO. “We look forward to this being the first of many renewable natural gas projects that move us toward a low-carbon future.”

Every year, the Bureau of Environmental Services processes 28 billion gallons of wastewater. A natural byproduct of sewage treatment is methane, a potent greenhouse gas. For years, Portland has been capturing a portion of this methane gas to produce electricity. The rest gets burned and released into the atmosphere. When the project is fully up and running in 2019, Portland will capture almost all of the methane from the wastewater treatment plant and convert it to RNG. That means that every year, the City will replace more than one million gallons of dirty diesel fuel with RNG, eliminate 21,000 tons of greenhouse gasses, and generate more than $3 million each year for its ratepayers. Simultaneously.

This is the City of Portland’s first CNG facility, and will provide clean fuel for the city and contractor vehicles serving the plant. For now, they run on conventional natural gas; when the city’s RNG infrastructure is up and running in late 2019, they will run on RNG. Soon the second part of the project will come to fruition and RNG will be placed into NW Natural’s pipeline and mixed with conventional gas.

By capturing methane from human waste and using it in new ways, Portland and NW Natural are on the road toward a clean and green future.

—Sources: AGA, The City of Portland, Ore.

– This article appeared in the Gas Technology supplement.

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