Published on November 22nd, 2013 | by The Kitsap Scene


Some Washington ferries may soon be fueled by natural gas

Washington State Ferries has submitted a plan to convert six ferries to run on liquefied natural gas to the U.S. Coast Guard. WSF says the conversion would save them money on fuel costs and reduce emissions.

The proposal, to convert six Issaquah Class ferries to run on liquefied natural gas, follows more than three years of study, according to a press release from the Washington State Department of Transportation.

WSF submitted its proposal to the Coast Guard Nov. 18 in a formal letter of intent and waterways suitability assessment, according to the release. It marks the official starting point of the Coast Guard’s review process, according to the release. WSF expects a finding from the Coast Guard in 2014.

“Fuel is WSF’s fastest growing operating expense,” said David Moseley, assistant secretary for the Washington State Department of Transportation, Ferries Division. “Replacing diesel with LNG on the Issaquah Class ferries could result in very substantial savings on fuel over the remaining 30 years of their service life. This will also mean a cleaner, more efficient future for our fleet by significantly decreasing emissions.”

According to the release, the average Issaquah Class ferry carries up to 124 cars and 1,200 passengers, serving on some of the state’s busiest ferry routes. Converting the fuel systems from ultra-low sulfur diesel to natural gas would significantly reduce emissions according to WSDOT’s Air Emissions Model. That includes an 89 percent reduction in particulate matter, 61 percent reduction in nitrous oxide, 28 percent reduction in carbon dioxide and a 59 percent reduction in sulfur dioxide.

WSF would install main propulsion engines that use natural gas and retrofit natural gas fuel tanks on the decks of the six ferries. The proposal calls for phasing in the conversions to avoid schedule changes or delays. Once the ferries are converted and are back in service, they would be fueled overnight in a process similar to how diesel ferries are refueled.

WSF has studied the benefits of alternative fuels and evaluating the feasibility and safety of liquefied natural gas since 2010, according to the release.  The process included the U.S. Coast Guard, multiple agencies at the state and local level, private industry organizations, the Washington State Joint Transportation Committee and consultants including Cedar River Group and Det Norske Veritas, the world’s leading authority on passenger ferries fueled by liquefied natural gas.

WSF concluded its study process by issuing the final waterways suitability assessment, which includes a safety and security assessment and a risk-management plan, the release states. The study found that WSF’s proposal is “inherently safe with risks as low as reasonably practicable.”

Use of liquefied natural gas to power passenger ferries has been proven technically and operationally feasible worldwide for more than a decade, with Norway operating LNG-fueled passenger vessels since 2000, according to the release. The release also states it’s becoming an efficient alternative fuel for buses and semi-trucks.

For more information on the project, go to

More information about the LNG project is available at the project website.

Photo by Walter Siegmund/Wikimedia Commons

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