All of Washington State Agency’s CNG Buses Run on Landfill Gas
From Pipeline Via ‘Wheel’ Deal Approved in June by the U.S. EPA
The Seattle area’s Pierce Transit is now fueling all of its CNG buses – approximately 143 of them – with renewable natural gas based on production at King County’s Cedar Hills Landfill. U.S. EPA approval allowing for RIN credits was received on June 5, says the Western Washington Clean Cities Coalition. updated August 16
Pierce Transit is believed to be the first such agency in the nation to switch whole-heartedly to biomethane, WWCCC says.
The RNG is purchased through Mercer Island, Wash.-based Cost Management Services, which has handled the agency’s natural gas fuel since 2000. The fuel is cleaned up and injected into the pipeline grid and sold via a contractual arrangement sometimes referred to as “wheeling.”
Credit for Using a Renewable Fuel
In this way, “producers of RNG in the Northwest can deliver to California, Utah, Wyoming, Colorado, Washington, and Oregon,” says CMS sales director Ted Lehmann.
“We have a fleet that is taking advantage of the RNG and it’s being traded appropriately and properly and legally for RINs,” says Stephanie Meyn of WWCCC. Credits earned under the EPA’s system of Renewable Identification Numbers effectively reduce the cost of fueling the buses.
RIN credits are part of the federal agency’s Renewable Fuel Standard program, known as RFS2.
BEW for Landfill Gas Purification
“It sends a really important signal to other fleets that are using CNG,” Meyn told F&F.
“As diesel prices per gallon fluctuate wildly,” states the Pierce Transit announcement, “the rate per therm for natural gas has been relatively stable.” The agency says it spends about $.70 per gallon equivalent on average for RNG, about the same as for CNG.
The Cedar Hill biogas is purified by Maple Valley, Wash.-based Bio Energy Washington. BEW uses a variety of technologies, including PSA (pressure swing adsorption) and membrane/molecular sieve techniques, says WWCCC project manager Scott DeWees.
As much as 10,000 cubic feet per minute of landfill gas had previously been flared at Cedar Hill, according to a BEW fact sheet.
CNG Was Already Saving Money for Pierce Transit
The current contract with CMS commits Pierce to using 5,000 therms of RNG per day. “However, senior manager of maintenance Bill Spies reports that Pierce Transit is currently using about 6,000 therms per day and is likely to use more as service hours increase.”
Even prior to the move to RNG, the agency saved about $2.4 million in its 2013 budget by purchasing CNG. Pierce says it also earned $775,000 in alternative fuel tax credits, “and is already starting to receive modest rebates for its recent move to RNG.”
“Pierce Transit will reduce the carbon emissions of its fleet by 80%,” project manager Scott DeWees said in the agency’s release, “while also investing in our regional economy.”
‘The Natural Next Step’
“While the financial benefits of using natural gas for fuel are significant, and the rebates for RNG are an added bonus, the move from CNG to RNG is just the natural next step,” said Pierce Transit CEO Lynne Griffith. “It is just one more way that Pierce Transit demonstrates its commitment to the environment and continues its long history of pioneering sustainable, environment-friendly operations.”
Until 2010, all of Pierce Transit’s buses were fueled by compressed natural gas (the switch from diesel started in 1986). Federal grants backed the purchase of 15 diesel-fueled hybrid electric buses by Gillig this past April.
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Source: WWCCC and Pierce Transit with Fleets & Fuels follow-up