Vessel owners and operators are concerned with the cost of increasingly restrictive air emission requirements. The use of LNG fuel instead of diesel or gasoline is gaining popularity due to LNG’s low cost and potential environmental benefits. Glosten studied converting the Washington State Ferries 144-car ferry design to liquefied natural gas (LNG) propulsion.

Multiple Factors at Play
While there are advantages to LNG use, there are still a number of challenges. Converting or replacing existing machinery with gas capable machinery is costly, considerable space and volume are required for the LNG fuel tanks and associated piping is challenging. And, LNG supply is still limited.
USCG Weighs In
To support the study, Glosten developed a preliminary design for both dual fuel and single fuel (LNG only) engines. The operational savings for a single vessel were significant, even considering the initial capital cost of the engines. Switching to natural gas fuel will significantly reduce emissions. The United States Coast Guard (USCG) reviewed the design and provided extensive feedback as well as a written response, showing their willingness to work with owners early in design development until official rules are published.
In order to quantify the costs and benefits of using LNG, Glosten developed a concept design and a review of the economic, regulatory, and environmental issues. We concluded that the conversion of Washington State Ferries to LNG fuel is both technically feasible and cost effective, although some technical and regulatory challenges remain.
Significant Fleetwide Savings
An independent review by the State of Washington Joint Transportation Committee confirmed that LNG can provide significant savings in fuel costs for Washington ferries, and recommended that WSF continue to develop a strategic fleetwide plan.
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