Electrifying!

An electric revolution is under way in the ferry sector. America’s largest ferry network, Washington State Ferries, has announced plans to deploy plug-in hybrid vessels on most of its routes. Norway’s leading ferry operators, Norled and Fjord1, are deploying multiple all-electric vessels for their shorter runs. In Canada, BC Ferries has just taken delivery of its first two hybrid-electric vessels. 

Many other operators are considering diesel-electric power, which would give them the flexibility to add new energy sources later. If electrification is the future for ferries, then Niagara Falls is a good place to find a preview.

Maid of the Mist

The Maid of the Mist sightseeing tour at Niagara Falls has been running since the 1840s with a brief hiatus for the Civil War. Its operations have stayed essentially the same over the years except for the transition from steam to diesel. 

The passenger dock sits on a narrow strip of land at the base of the Niagara Gorge, just below Horseshoe Falls and about a mile and a half above a set of powerful rapids. There’s no navigable waterway in or out, and no access road. Passengers arrive by elevator from a parking lot at the top of the gorge. For operational purposes, the site is isolated – so isolated that it requires its own “shipyard,” a $30 million maintenance pad complete with a 200-ton pedestal crane at the base of the gorge. 

When it came time for Maid of the Mist to replace its two boats, the company decided to look at all available options. Its operating requirements lined up with something unexpected – the world's first battery-electric car ferry, the Ampere. Not precisely, but close enough that it caught the attention of Maid of the Mist President Christopher Glynn. 

"The Ampere was of interest for a lot of reasons,” said Glynn, speaking at an ABB-sponsored forum in New York, “one of which was it parallels our operation in time: 20 minutes on the water and then 10 minutes of charging at the dock. And we thought, if battery-electric can be done in a vessel that size, certainly it can be done in a smaller vessel like one of ours. And you know, we're at Niagara Falls, one of the largest sources of hydroelectric power in the world."

To build its new all-electric vessels, Maid of the Mist worked with ABB Marine and Ports, a leader in electric propulsion systems. The design team took a conservative approach to risk management and opted for full redundancy. The catamaran hull contains two of everything required to maneuver with a separate propulsion system, battery storage bank, electrical bus and steering system in each pontoon.  The first of the two boats began trials in mid-December, and Maid of the Mist expects both to enter into operation in 2020. 

It was an ambitious project, even for a passenger operator serving 1.6 million visitors a year. Public perception was a key motivating factor in green-lighting the extra investment, says Glynn: "This is a famous tourist attraction in a very special, environmentally sensitive place. The overall victory for us is not in incremental savings on operating cost."

Passenger vessel operators like Maid of the Mist serve the public directly, and electrification seems to be happening first in their sector of the industry, notes Catherine Hale, East Coast representative for Elliott Bay Design Group: "The biggest thing with ferries moving forward with batteries and hybrid-electric is that the public is pushing them. And the public is their customer." 

Grid Issues

Maid of the Mist's boats demonstrate the potential of all-electric power but also its limitations. They operate on a short, fixed rotation with frequent calls at one site, ideal conditions for recharging. Longer, more complex routes require more shoreside infrastructure (and therefore more cost). In addition, Maid of the Mist is just a few miles from the fourth-biggest hydroelectric plant in the U.S., which means grid power is both green and plentiful. 

Grid capacity is a critical factor for commercial-scale marine power, says Jennifer States, Senior Consultant for DNV GL and Project Director for the Washington Maritime Blue initiative: "That’s what I would say is the biggest challenge right now. The plug-in infrastructure, that's solvable. It's about the grid impact and working with your electric utility.”

These challenges make electrification difficult for more complex ferry systems, adds Ethan Wiseman, Associate Vice President & Fleet Manager for the NYC Economic Development Corporation, the force behind the NYC Ferry system. The NYC Ferry network runs small, passenger-only vessels on six routes with about 20 stops in Manhattan, the Bronx, Brooklyn and Queens. The operating profile on these routes varies widely with compact circuits along the East River contrasting with longer runs to Soundview and Rockaway.

"We're always looking at options to decarbonize our operation,” Wiseman says, “but we're finding there’s no one solution that fits all. We have routes that operate at lower speeds and higher speeds, shorter and longer ranges, some with quite a few stops. This makes battery-charging technology challenging. We also commingle vessels across different routes. When you start going into bespoke solutions on a route-by-route basis, the operational advantage goes away."

Going Big    

America’s largest ferry owner by tonnage, the State of Washington, is heavily in favor of electrification. Under the direction of Governor Jay Inslee, who has made climate action his defining issue, Washington State Ferries has adopted an ambitious plan: It wants to have 22 plug-in-capable hybrid vessels and 17 shore-charging stations by 2040. 

It’s already ordered a series of up to five new hybrid ferries from Vigor Industrial, and it’s working with Siemens on a battery-hybrid retrofit for its largest diesel-electric vessels, the Tacoma, Puyallup and Wenatchee. The first conversion is slated for completion in 2021-22 at an overall cost of about $40 million. That expense may seem high, but it’s buying reliability. 

"When you start to get into the numbers and looking at how they're going electric, there's a lot of redundancy and risk aversion built into that price,” says Jennifer States, Washington Maritime Blue Project Director. 

Risk Factors

Some public operators aren’t sure that ferries are the right vessels to use with new technology since they are obligated to provide a regular service. 

“You cannot use passenger ferries as experimental platforms,” says Captain James C. DeSimone, COO of the Staten Island Ferry. “People are relying on this thing going back and forth to work, school, doctor's appointments. The vessel has to be very, very reliable, and any technology you're going to step into has to be proven technology.”

All-electric power has fewer moving parts than diesel, and proponents argue that it has inherently lower maintenance requirements and higher uptime. However, battery-equipped vessels come with a major liability: Lithium-ion batteries have the potential for fire and toxic gas production if overcharged, shorted out or damaged. Additionally, the gas created by a failing cell can accumulate within an enclosed compartment, creating an explosion hazard.

Engine room fires are an age-old problem, but battery accidents are a bit different as witnessed by the fire and subsequent explosion aboard the Norwegian electric ferry Ytterøyningen last October. Investigators believe a gasket failed on a water-based cooling system for a battery pack, causing a cell to catch fire. It was brought under control, but an adjacent compartment exploded 12 hours later. The activation of a saltwater sprinkler system likely "contributed to escalating the incident" rather than controlling it, the battery’s manufacturer said. 

According to a study released in January by DNV GL, these new risks will have to be addressed with new engineering decisions – that is, the right combination of compartmentalization, battery management technology, fire detection and firefighting systems. The study determined that in the event of a battery failure, powerful ventilation is needed to remove explosive gases from the compartment – the opposite of the fire damper-plus-CO2 procedure for an engine room fire. 

In addition, the study showed that conventional sprinklers actually increased the risk of an explosion by displacing flammable gas into concentrated pockets. DNV GL also identified many effective ways to manage battery fire risks – too many to list here – but some of these new methods will require adjustment in an industry with hard-earned firefighting instincts.

Ferry of the Future

Once these technical questions are resolved, the ferry of the future might be quite futuristic indeed. 

One company is working to combine battery-electric propulsion and vessel autonomy, removing both the diesel engine and the crew. Zeabuz, a new startup founded at the Norwegian research university NTNU, plans to develop and commercialize small, electric, service-on-demand passenger ferries for short routes. 

“Autonomy fits like a glove with electric ferries,” says Asgeir J. Sørensen, Director of NTNU's Center for Autonomous Marine Operations & Systems. “This enables better control, optimal operation, safety and maintenance.” 

Electrification is advancing fast with the help of digital, connected technology, but this leap into the future is also a return to the past. The all-electric passenger ferry predates the advent of the diesel engine. In the 1890s, while Rudolph Diesel was perfecting his invention at engine builder Maschinenfabrik-Augsburg-Nürnberg (MAN), for-hire electric launches were already shuttling passengers back and forth along the Thames. One of these fashionable vessels, the Mary Gordon, later fitted an aircraft engine on deck in what may have been a rudimentary “hybrid-electric” trial. 

In some ways, the future looks very familiar. – MarEx  

Paul Benecki is the magazine’s Americas/Europe Editor.