Ferry to be Converted to Battery Hybrid System

Thursday April 25, 2013

The U.S. state of Washington plans to convert a 144-car ferry, the Hyak, to a diesel-battery hybrid propulsion system, reducing its fuel consumption by 20 percent, the local newspaper Kitsap Sun reports.

The $22 million conversion would keep the vessel's four main engines and four diesel generators while adding batteries and a variable-speed control system, allowing it to store extra power for later use.

The ferry's operator, Washington State Ferry (WSF) estimates the system will save $21.5 million in fuel costs plus $1.2 million in maintenance over the ship's remaining life of about 16 years.

The conversion, which is funded mainly with federal money, is scheduled to begin in October 2014, after a new ferry is delivered, but a contract for the work will be awarded in June.

The Hyak was built in 1967, and, because it never received a planned midlife renovation, it would have had to be retired earlier than originally planned without the conversion.

"The Super Class is an important class in our fleet, and we really need that capacity," said George Capacci, WSF deputy chief for operations and construction

Aside from the cost savings, the ferry operator says  the conversion will reduce carbon dioxide (CO2) emissions by 2,674 metric tonnes per year, particulate matter (PM) by 1 metric tonne per year and nitrogen oxide (NOx) by 17 metric tonnes per year.

Battery hybrid vessels are getting attention from many the industry lately, with Nippon Yusen Kabushiki Kaisha (NYK Line) recently announcing the launch of a diesel-battery tugboat and Det Norske Veritas (DNV) saying that a pilot project shows that such a system can provide payback in less than a year.