Impact Series

How Washington state plans to create the world’s largest hybrid-powered, auto-carrying ferries

Aboard the Washington State Ferries’ MV Wenatchee with downtown Seattle in the distance. The Wenatchee is one of three Jumbo Mark II class ferries slated to become an electric-diesel hybrid. (GeekWire Photo / Lisa Stiffler)

The world’s maritime industry is beginning to transition from air-fouling, climate-warming diesel fuel to cleaner energy — and Washington state’s ferry fleet is getting on board.

The state Department of Transportation is putting together a deal to convert three of its largest ferries into electric-diesel hybrids, and recently marked an agreement to build up to five new, slightly smaller hybrid ferries.

“The entire traditional [maritime] industry is shifting around the globe. It’s almost like the shift from sail to steam,” said Joshua Berger, the maritime sector lead for Gov. Jay Inslee at the state’s Department of Commerce.

Washington leaders and industries are eager to be a player in the field, and view the creation of hybrid power ferries as a key part of their strategy. Inslee, who made climate change the centerpiece of his campaign for the Democratic presidential nomination, launched the Washington Maritime Blue 2050 initiative two years ago with the goal of becoming “home to the nation’s most sustainable maritime industry by 2050.”

In a plan released in January, the state earmarked the project to invest in electric-hybrid power and dockside electrical recharging capabilities as one of the biggest planned capital expenditures for the ferry system over the next two decades.

A photo of part of one of the four diesel generator sets on the Wenatchee. Two of the sets will be replaced by lithium battery packs on each vessel. (GeekWire Photo / Lisa Stiffler)

The converted ferries will be the largest auto-transporting, hybrid ferries in the world.

“We are creating a center for excellence for electrification in the maritime industry for all of North America,” Berger said.

Transportation is responsible for nearly one-third of the U.S. greenhouse gas emissions, and climate experts are eager for innovation and wider-use of electric technology. The push into electric-powered vehicles is growing in the auto sector as well, with Amazon announcing on Thursday a deal to purchase 100,000 electric delivery vans as part of its broader climate initiatives.

The hybrid technology used by the ferries is relatively straightforward and available off-the-shelf, local experts said. Scandinavian companies are building hybrid and all-electric boats in their countries, and Washington representatives have made repeat trips to Norway to learn about the technology. The ferries are logical candidates for operating as hybrids: they make relatively short transits with time between trips for recharging, compared to say cargo ships that travel great distances between ports.

The big challenges will be bringing the power to rapidly recharge the vessels’ batteries to multiple ferry terminals around Puget Sound, and adapting the technology for plugging in the ferries while the vessels unload and load vehicles and passengers. Most other electrified ships tie up alongside a pier. Ferries dock at either end of their more narrow bows, creating a novel situation for the mechanics of recharging.

Add to that “Puget Sound storms blowing up and down, which will add motion while the vessel is in dock,” said Ron Wohlfrom, vessel project engineer for Washington State Ferries. “So there’s the challenge of keeping it plugged in.”

Capt. Harlow Wood on the bridge of the Wenatchee. (GeekWire Photo / Lisa Stiffler)

That said, Wohlstrom and others are excited to bring the new technology to the state’s iconic ferries, which comprise the biggest ferry system in North America. Here’s the plan for converting the boats:

  • Three Jumbo Mark II class ferries — the fleet’s largest, capable of carrying 202 vehicles — will all be converted to hybrids
  • The first conversion should to be completed within two years
  • The 1990s-era Mark II ferries are due for overhauls to their propulsion control systems, providing a timely opportunity to convert to hybrid
  • The overhaul and hybrid conversion is projected to cost $35 million per vessel, but could go as high as $45 million
  • Washington’s $112.7 million share of the Volkswagen diesel pollution settlement will help pay for the conversions
  • Siemens, which built the ferries’ original propulsion system, will do the work

“These are the biggest gas hogs in the fleet,” said Ferries spokesman Ian Sterling, “so there’s a big payoff to converting them over.”

In addition to the conversions, the state is working with Vigor, a Seattle shipyard, to build up to five Olympic class electric-diesel hybrid ferries. Washington’s lawmakers have approved funding for construction of the first of the 144-car vessels. Construction should begin next year and could be completed by 2022. While the ferries will be hybrid, they’ll be able to run on solely electric power. The price tag for the new ferries is between $160-180 million, compared to $160 million for a non-hybrid vessel.

Skagit County, at the north end of Puget Sound, has proposed switching to an all-electric ferry to make the short crossing between the town of Anacortes and Guemes Island. The county needs to replace its 40-year-old diesel powered ferry, which has a capacity of 21 vehicles and 99 passengers.

The state’s larger Mark II ferries currently are powered by four diesel engines that each drive a generator. The generators make the electricity that powers the propulsion system, pumps, lights and other operations. At any given time, three of the diesel generators are in use.

Washington State Ferries spokesman Ian Sterling inside the “shaft alley” compartment on the Wenatchee. The long rod is the shaft that turns the propeller. There’s an identical shaft on the other end of the vessel, since the ferries alternate which side is the bow at each docking. The shaft alley will house the batteries when the ferry is converted to hybrid power. (GeekWire Photo / Lisa Stiffler)

In the conversion, two of the diesel generator sets are removed and replaced with a bank of lithium batteries. The batteries are twice the size of the equipment that they’re replacing, but there’s room for them. Compared to other ships, ferries have a larger below-deck footprint given their need for plenty of deck space to transport a maximum number of vehicles.

Keeping half of the diesel generators in place provides the option of using the engines to recharge the batteries if and when shore-side electricity is not available — something like how a Prius works. Using the engines to recharge the batteries can cut fuel use 30-to-50 percent compared to running the ferry’s propulsion off the engines directly. The ferries making the Seattle-to-Bainbridge Island run, for example, use about 5,000 gallons of diesel daily to make 10 round-trip crossings.

On a recent sailing, the captain of the MV Wenatchee, a Mark II ferry, and its engineers expressed a mix of interest, curiosity and concern regarding the plans to go hybrid.

“It’s exciting. They’ve never done anything like this on this side of the world,” said Capt. Harlow Wood from the bridge of the Wenatchee as it sailed to downtown Seattle.

“It could change the operations a little bit,” Wood said. But how it will play out is impossible to know at this point, particularly regarding the recharging arrangement. “We’ll make it work.”

Editor’s Note: Funding for GeekWire’s Impact Series is provided by the Singh Family Foundation in support of public service journalism. GeekWire editors and reporters operate independently and maintain full editorial control over the content.

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