Fleet NGVs Could Make for 100% Use of Plant’s Wastewater Biogas,
Expectation Is for Some 1,700 DGEs of CNG Per Day to Be Available
The City of Portland, Ore. has determined that natural gas vehicles represent the best use of surplus biogas from a local wastewater treatment plant. About 20% of the facility’s biogas is now flared, but could be processed into some 1,700 diesel gallon equivalents of compressed natural gas per day. updated March 17
Following the recommendation by the city Environmental Services unit, the Portland City Council has approved a contract for final design of a facility at CBWPT, the Columbia Boulevard Wastewater Treatment Plant, to convert biogas into CNG for natural gas vehicles.
Biogas purification technologies are being evaluated now, says wastewater engineering manager Paul Suto.
“The vehicle fuel option is the most economical and has the greatest environmental benefit because it will reduce diesel fuel use and cut greenhouse gas emissions,” states a release.
Garbage Trucks? City Vehicles?
“Environmental Services is exploring several possible uses for the fuel including selling it to a utility company, selling to Portland area garbage haulers to fuel trucks, fueling city vehicles, or fueling trucks that haul bio-solids for land application.” Because of the site layout, the city has decided against a general public access CNG station, Suto role F&F.
Portland reckons a cost of $10.9 million to design and construct a biogas processing and storage facility and a CNG fueling station at the CBWTP site, located north of the city. The Environmental Services unit is exploring grants and financial incentives to help reduce project costs.
Construction could start early next year and the facility could be operational by 2017.
Biogas Currently Used for Heat and Power
The city says that the CBWTP has long been moving toward 100% biogas re-use. Portland-based Malarkey Roofing Products has been buying biogas to help power its manufacturing for more than 30 years, and currently accounts for about 20% of the CBWTP’s output. Another 20% fuels boilers for building heat and the solids treatment process.
In 2009, the CBWTP installed two 850-kilowatt engine-generators that use about 40% of the plant’s biogas as fuel to generate electricity for the wastewater treatment process.
“Converting biogas to vehicle fuel will re-use practically all the biogas the treatment plant produces,” the city says.
The design contract is with HDR.
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Source: Portland City Council with Fleets & Fuels follow-up