Crowley Maritime executives detail the progress on their new 70-tonne bollard pull, all-electric tug for the Port of San Diego, and collaboration on a hydrogen-fuelled tug concept
The design of the electrical package for America’s first fully all-electric tug is in its final stages, with momentum building towards its debut at the Port of San Diego next year. One of the things you will not find onboard the vessel when it is commissioned is a diesel engine.
“It’s all cables down below, no mechanical engines,” said Crowley Maritime vice president, construction and engineering Coulston Van Gundy.
“It’s a complete electrical package; it’s not meant to run on diesel at all,” added Crowley Maritime business development director Bryan Nichols.
In an exclusive interview with Marine Propulsion, Mr Van Gundy and Mr Nichols detailed the groundbreaking design, development and construction of eWolf, a zero-emission ship assist and escort tug that will serve ships calling at the Port of San Diego. The 25-m tug will generate 70 tonnes of bollard pull without a single drop of MGO.
“Just like batteries, we really need to start testing the market and understanding those limits”
Instead, power for the tug will be provided by batteries, which will be delivered to Master Boat Builders by the end of 2022. Progress on the hull and superstructure of eWolf is well underway at the Coden, Alabama, shipyard according to Mr Van Gundy.
Under a contract with Master Boat Builders, ABB is supplying the end-to-end electric propulsion system to sustain emissions-free operations. The solution will include a 6 MW/hr energy storage system (ESS).
Batteries provide power to the propulsion system almost instantaneously, making ship-assist operations more efficient with no emissions while delivering reliable ship assist and harbour escort services.
When it is commissioned in mid-2023, the fully electric tug will replace a conventional diesel-powered one that consumes 30,000 gallons (about 113,500 litres) of diesel annually. Crowley estimates that in its first 10 years of operation, eWolf will reduce NOx by 178 tonnes, diesel particulate matter by 2.5 tonnes, and CO2 by 3,100 metric tonnes, compared to a conventional tug.
Crowley released its first sustainability report this year, outlining its efforts to reach net-zero emissions by 2050. To accomplish this, Crowley is targeting greenhouse gas (GHG) reductions of more than 3.7M metric tonnes per year across its business. The US shipping firm’s investments in eWolf, LNG development and LNG-fuelled container roro vessels for Puerto Rico and offshore renewables are all seen as advancing this ambitious cause.
Benefitting from previous development
ABB vice president, sales, marine systems and process automation Ed Schwarz said the development of eWolf will benefit from deeper North American team knowledge and experience gained from Maid of the Mist’s two fully electric tour boats – which have been operating for two years at Niagara Falls – and Washington State Ferries’ ambitious fleet electrification efforts.
ABB was selected by Vigor Fab to supply the hybrid-electric propulsion and ESS for Washington State’s new hybrid-electric Olympic-class car ferries, the first of which will be delivered in 2024. The project is part of a larger plan by WSF to replace 13 existing diesel-powered ferries with hybrid-electric newbuilds and convert six others to plug-in hybrid by 2040. This will require shoreside charging capacity to be installed at many ferry terminals.
Speaking to Marine Propulsion during the ABB FIA Formula E World Championship’s 2022 New York City E-Prix held in Red Hook, Brooklyn in July, Mr Schwarz outlined some of the challenges with engineering Maid of the Mist’s two all-electric ferries, James V. Glynn and Nikola Tesla.
“Port and shoreside charging infrastructure play central roles in vessel design”
“As far as the implementation of new technology, there are always challenges,” said Mr Schwarz. In an effort to manage expectations, Mr Schwarz cautions vessel owners that the processes of design, execution and commissioning are more complex with all-electric propulsion than diesel mechanical. This is especially true with industry-first projects such as Maid of the Mist. “We were working with the Coast Guard on approvals of rules for lithium-ion batteries for propulsion that did not exist,” he said.
“These systems require a tremendous amount of engineering upfront,” he said, necessitating “commitment and focus on the end result” from the owner, shipbuilder, integrator, designer and regulator. Port and shoreside charging infrastructure play central roles in vessel design, he said.
Shoreside charging key
“The rate of charge is one of the critical components into the complexity of the systems on both sides. Really matching that rate of charge is what we want to understand initially when we’re designing the assets”, said Mr Van Gundy.
“We’re going to charge at 1 MW per hour, but the vessel will be capable of charging at a more rapid rate,” he added.
Working with Watts Marine (formerly Cochran Marine), Crowley is serving as the prime contractor for developing rapid shoreside charging infrastructure for the tug. At the Port of San Diego, the recharging station will store 3 MW of power onshore in batteries. Mr Nichols noted that some European ports have built automated charging stations, but those require “fairly large infrastructure” that is used by multiple vessels. But specifications outlined for the Port of San Diego require the crew to handle the charging.
Once the tug is fully charged at the dock, the idea is to have enough power to operate for the entire day of harbour operations. Multiple operational factors, however, will determine just how much the all-electric tug is able to accomplish with its single charge. These factors, noted Mr Nichols, include how much the tug “uses for a docking, if it’s windy, if there’s current, how long you are out there, how much you are pushing on it”. He said in a “worst case scenario”, the ship-assist tug would return to the dock at midday following its morning run to recharge for its evening run.
Safety of any tug operation is critical, especially the game-changing technology represented by eWolf. “We have been engaging with the crews since day one,” said Mr Van Gundy, sharing information about the ergonomics of the vessel, power requirements and vessel layout. “Throughout the construction process they’ve continually been involved with plan reviews to help them understand how the design and engineering is progressing.”
ABB is also supplying its ABB Ability Marine Pilot Vision for eWolf, which provides the master with an augmented reality of the vessel’s surroundings by incorporating a range of sensors to enhance situation awareness.
Added Mr Van Gundy: “As part of our contract with the builder, ABB is providing a dedicated training session through commissioning and post-delivery for the mariners.”
