Pacific Power Group, Vancouver, Wash., says its engineers have developed a propulsion system and exhaust treatment system for two new San Francisco Water Emergency Transportation Authority (WETA) ferries that will achieve U.S. Environmental Protection Agency Tier 4 standards without using diesel particulate filters – making them the cleanest operating passenger ferries in the U.S.

Independent emissions tests, conducted at PPG’s Kent., Wash., location and verified by Infowedge, El Dorado Hills, Calif., and The University of California at Riverside Center for Environmental Research and Technology, were completed in January. Those results showed “the system’s emissions are believed to be lower than any currently-operating passenger ferry in the U.S.,” according to the company.

The propulsion package by PPG includes two MTU 12V4000M64 1950 HP engines and ZF 7600 reduction gears. MTU Series 4000 engines provide clean-running operation that helps lower the ferries’ emissions output.

The MTU engines are previously certified to EPA Tier 3 marine emission levels, and with the added exhaust after treatment system, EPA Tier 4 Final level performance is achieved without the use of diesel particulate filters. The company says those Series 4000 engines also offer increased safety, lower fuel consumption and greater reliability for the commercial passenger vessels.

The power package will go into two Incat-Crowther designed 135’x38’ aluminum catamarans, now under construction at Kvichak Marine Industries Inc., Seattle. The ferries will each carry up to 400 passengers at around 27 knots service speed, and replace two boats in WETA’s fleet of 12 that are nearing the end of their expected 25-year service life. The new boats are expected to be in service by summer 2017.

PPG engineers worked closely with Kvichak to develop a system that physically fits the vessel design, meets weight goals and provides easy installation and maintenance for WETA. While keeping weight and space claim to a minimum, the system will reduce an estimated 10 tons of nitrous oxide, particulate matter and carbon monoxide annually from vessel emissions, by using selective catalytic reduction and diesel oxidation catalyst technologies.

PPG has supplied WETA with propulsion systems and support for many years, including the propulsion for an earlier set of ferries in 2011 – the 118’x29’x6’ Gemini and Pisces, 149-passenger ferries designed by Incat-Crowther that exceeded then-current EPA Tier 2 emissions standards by 97%.

“As the demand for cleaner-operating vessels continues to grow, we’re proud to offer innovative, environmentally-friendly solutions that meet and exceed the unique demands our customers have for their vessels,” Bill Mossey, vice president of Pacific Power Group, said in announcing the test results. “The propulsion and exhaust treatment system created by our marine team and partners makes these ferries some of the greenest operating passenger vessels in the nation.”

Contributing Editor Kirk Moore was a reporter for the Asbury Park Press for over 30 years before joining WorkBoat in 2015. He wrote several award-winning stories on marine, environmental, coastal and military issues that helped drive federal and state government policy changes. He has also been an editor for WorkBoat’s sister publication, National Fisherman, for over 25 years. Moore was awarded the Online News Association 2011 Knight Award for Public Service for the “Barnegat Bay Under Stress,” 2010 series that led to the New Jersey state government’s restoration plan. He lives in West Creek, N.J.