By
Rebecca Gibson |
Washington State Ferries (WSF) plans to convert six of its Issaquah class-vessels to run on liquefied natural gas (LNG) to significantly reduce fuel emissions and costs.
Following three years of evaluating the feasibility and benefits of using LNG fuel in its vessels, the company submitted a formal letter of intent and a waterways suitability assessment to the US Coast Guard (USCG) on 18 November.
The proposal was developed in collaboration with the USCG, multiple state and local agencies, private industry organisations, the Washington State Joint Transportation Committee and consultants including Cedar River Group and Det Norske Veritas.
According to Washington State Department of Transport’s Air Emissions Model, converting the fuel systems is expected to reduce particulate matter by 89% and nitrous oxide by 61%. It is also expected to decrease carbon dioxide and sulphur dioxide by 28% and 59% respectively.
“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.”
If the proposal is accepted, WSF will install main propulsion engines and retrofit LNG fuel tanks on the top decks of the 1,200-guest ships. Work will be carried out in stages to avoid schedule changes or delays. Once vessels are converted and back in service, they would begin a routine overnight, out-of-service refuelling process similar to current diesel refuelling.
WSF expects the USCG to issue a report on the LNG conversion proposal in 2014.