LNG use as a marine fuel is both practical and cost effective and has been used in Norway for fueling ferries for over a decade. A high-level discussion of adapting the WSF 144 vehicle ferry design for use with LNG fuel indicates that the volume exists to add LNG tanks of adequate size while still allowing weekly bunkering. Although the capital cost of the LNG engines and tanks is high compared to conventional diesel equipment, fuel cost savings of $870,000 per year are estimated at today’s prices. For pure gas propulsion engines NOx emissions reductions will be at least 90% and PM and SOx emissions will be reduced nearly 100%. CO2 emissions reductions from pure gas propulsion engines will be approximately 20%.

Full paper: LNG Use for Washington Ferries

Authors: Sean Caughlan, PE; David W. Larsen, PE