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Jun 20, 2023

ABB helps iconic Maid of the Mist boats go green

By Paul Heney | June 5, 2023 The new electric Maid of the Mist sits at the dock,

By Paul Heney | June 5, 2023

The new electric Maid of the Mist sits at the dock, behind one of the old diesel models.

Anyone who's visited Niagara Falls in the summer has surely watched the famed Maid of the Mist boats ply the waters of the Niagara Gorge. The ships, which appear tiny from above, seem to get perilously close to the thundering water from both the American and Canadian falls, crashing down roughly 200 feet. Now, the American operator of the two ships has decided to move into 21st Century technology with all-new craft that use ABB zero-emission technology to power the fully electric ferries. These new ferries can hold more than 500 passengers each and replace the former diesel vessels.

Design World recently received an exclusive invite to tour the new boats, including getting down below the hatches and taking a ride into the mist.

The Maid of the Mist Corp., founded in 1846, is family owned and operated. This step forward to demonstrate the commercial viability of all-electric boat technology has attracted global attention to the company. The Niagara boats are believed to be among the first all-electric vessels — but won't be the last. Industry experts say that passenger ferries, river barges, harbor tugs, and dredgers are well-suited to all-electric operation.

The new electric Maid of the Mist heads toward the falls.

ABB noted that marine vessels are one of the largest contributors to transportation emissions (3-5% of global CO₂ and more than 5% of global SOx), so electrification of shipping cannot come soon enough. Today, it would be difficult to build 100% electric ocean-going vessels. However, as equipment becomes smaller and more cost-effective, new opportunities keep opening. Autonomous, all-electric seagoing vessels may be possible and practical in years to come.

New horizons in marine battery technologyGlobal interest in marine electrification is being spurred on by, for instance, new International Maritime Organization rules, such as the 2020 IMO fuel sulfur regulation, which will reduce the limit on the sulfur content of bunker fuel. Maritime operators are, therefore, keen to explore fuel cell technology.

Jon Diller, the commercial director for Kansas City-based Spear Power Systems, explained that the batteries used on the ferries are split between left and right sides; each side has 168 kWh of embedded energy, so it is a 316- kWh vessel. The batteries are arranged based on the Spear energy module, which uses a rectangular pouch cell from LG Chem.

"Each module has 64 amp hours, which makes it roughly 21 times the size of the cell that's in a cell phone. We take two of those and put them in parallel, and then take 24 and put them in series. That produces a module that has 11.3 kWh of embedded energy. That's an 11-kWh unit, and it has a 100-volt maximum voltage," Diller said. "We then take that module and put it in series with other modules to get to the system voltage that's desired to work with the propulsion system. In this case, the drives want their voltage range to operate somewhere between 640 volts and 420 volts. So, I go with seven modules in series to get to a maximum voltage of 100 volts."

From a safety standpoint, Diller said that there's a battery management system to stop the electrical abuse of the battery. It prevents operators from doing the things that will cause a battery to catch on fire: overcharging it, charging it too fast, charging it when it's frozen, or charging it after it's been depleted to a 0% state of charge.

The ship's power distribution station, located below the main deck copy.

"If you can prevent people from doing those kinds of things, you can prevent an internal thermal runaway," he said. "But each compartment, each battery, will have a thermal runaway on one section. It is totally disconnected from the next section," he said. "For safety, what am I going to do with it if it catches on fire? I use the passive thermal management structure that's built into this battery to limit the propagation of the event — and then I’m going to mitigate it by removing the products of the thermal event. There's an aluminum plate on the top and bottom of each module, effectively both the case and the heat exchanger. That aluminum plate has sufficient thermal mass, given its connection to the thermal energy of the cell, to pull the heat out of a burning cell fast enough to prevent it from raising the temperature of the adjacent cells to the thermal runaway point."

Diller said they tested the system by putting the battery at its maximum operating temperatures and then overcharged the center cell pair and the center module at 150% until it popped. This took 12 minutes. When that happened, the temperature of the burning cell was around 800° C. But the temperature of the adjacent cell registered at only 80° C. The temperature of the adjacent module on top was 60° C and the temperature of the adjacent module and bottom was 50° C.

He further explained that this safety system, called single-cell propagation control, is not required for marine batteries, but it is required for Spear batteries.

Charging and propulsionThe Maid of the Mist boats set off from a downstream dock to head toward the base of Niagara Falls every 30 minutes, serving an impressive 1.6 million guests each year. While the ferry is docked and passengers are embarking and disembarking, the new boats’ lithium-ion batteries are partially recharged. The seven-minute charge provides a battery boost enabling the vessel's dual electric propulsion motors to maintain their total output of 400 kW (563 hp). Each trip consumes about 38 kWh. The batteries still have 80% power at the end of the working day but are charged up to 100% each night. And completing a bit of an ironic circuit, the electricity needed to charge up the 316 kWh battery packs comes from zero-emission hydropower. (Thanks, Niagara Falls!)

The Maid of the Mist hooked up at the daytime charging station.

According to Esteban Guerrero, master electrician for Maid of the Mist Corp., they have two charging stations.

"We have a daytime charging station, and we have a nighttime charging station. The nighttime charging station is a trickle charge, with about 30-40 volts. The one we use during the day has a high output of 600 amps that charges the unit within seven minutes," he said.

Guerrero also described how there are two motors operating thrusters in the back of the boat (for propulsion), and there are two valve thrusters in the front that help with directional control. The result is a very maneuverable craft.

One of the ship's rear thruster L drives.

The old boats used a common straight shaft diesel design for the rear propeller. Kyle Taylor, one of the captains at the company, explained that if you were to simply convert that setup to electric, but using the same basic transmission and components, the result would be way less efficient. So instead, the team decided to go with azimuth drives operating a propeller underneath the water. "It just made total sense for what we were doing here," said Taylor.

Taylor said that the rear thrusters use L drives manufactured by Veth Propulsion (a division of Twin Disc, Inc.) and that maximizing lifespan and minimizing downtime are key concerns of Maid of the Mist Corp.

"These L drives have a super-low profile and are easy to maintain," Taylor said. "We’re spoiled for space here, so we can crawl all around them. The goal is to have a warehouse full of spare motor drives and all the other components to minimize downtime. Our Veth drives are about 250-hp equivalents; there's one per side, a 200-kW electric motor that we run at a maximum 80% output. So, it's the same as the batteries — we don't really charge above that or use components above that. We just try to get a long lifespan out of things. Our batteries are guaranteed for 10 years by our contract with Superior. That's got to be the same thing with the electric motor."

Even more greenABB is supporting e-mobility for applications outside the maritime world as well — for example, with public and private EV charging solutions. By early 2019, more than 10,000 ABB DC fast chargers had been sold in 73 countries. Looking ahead, products such as the company's Terra HP high-power charger are designed to accommodate the higher-­capacity batteries of tomorrow.

Additionally, ABB is helping stakeholders across the globe establish electric bus services that reduce human impact on the environment. The company launched its first DC fast charger in 2010, the first nationwide DC charging networks in 2012, and the first eBus charging networks in Europe in 2016.

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