Dave Lee, Priscila Faester ABB Inc. Marine & Ports Miramar, FL, United States, firstname.lastname@example.org, email@example.com
Although shipping accounts for just 2 to 3 percent of annual global CO₂ emissions , this percentage could rise dramatically as other emitters decarbonize. The shipping industry is exploring ways to reduce emissions – primarily by replacing marine diesel engines with electric motors powered by efficient, high-performance and compact batteries, such as those found in electric vehicles.
Whereas many diesel-engined vessels spend much time at sea, far from land, one class of marine craft operates a busy trade exclusively around ports and, therefore, close to highly populated areas: the tugboat.
The Port of San Diego and the eWolf
The important role that tugboats play is often overshadowed by the presence of their more spectacular sisters – such as vast Panamax container ships. However, such ships are completely reliant on the assistance of tugboats to maneuver safely into and out of ports. In busy terminals such as the Port of San Diego, tugboats can be active day and night, which raises noise and emissions issues. For these and many other reasons, tugboats are ideal candidates for a move to electrical propulsion.
In California, the Port of San Diego is at the forefront of the transition from diesel to electric propulsion for workboats →02. The port authorities see the many advantages of battery-powered vessels – not only do they virtually eradicate emissions but they also make the local environment cleaner and quieter for residents. Working conditions are improved for the crew, too and vibrations are all but eliminated. Marine noise pollution is also substantially reduced, benefiting the sea life for which this part of the world is famous.
The first electric vessel to ply its trade for the Port of San Diego will be a tugboat, named eWolf, due for delivery in mid 2023 →03. Built by Alabama-based shipbuilder Master Boat Builders, Inc. for Crowley, the eWolf will be the first all-electric, battery-powered harbor tug ever built and operated in the United States and only the third of its kind to enter operations worldwide.
ABB has provided electric systems on board vessels for more than 110 years. Today, well over 1,300 ships employ ABB’s electric systems. Leveraging the company’s long experience in marine electrical engineering and propulsion, ABB has worked with Crowley, Master Boat Builders and the Port of San Diego to supply the electrical infrastructure that comprises the backbone of the eWolf’s propulsion as well as its many ancillary electrical systems →04. Crowley is an excellent engineering partner as, with over a century of harbor workboat operations and over 60 years of vessel design experience, they have become widely known as a pioneer in the sustainable workboat space.
A sustainable design
The eWolf project presented the opportunity to design the vessel from scratch, which meant sustainable technology and design features that are also efficient and safe for operators could be prioritized. These innovative solutions involve many aspects of the overall design, from the pilothouse to the bulwarks.
Emissions goals for the project call for the operation of the new tug to eliminate 170 tons of nitrogen oxides (NOx), 2 tons of diesel particulate matter, and 3,100 tons of carbon dioxide compared with a conventional tug over the first 10 years of operations.
A DC grid on the boat
ABB’s Onboard DC Grid™ is the backbone of the enabling power technology for the eWolf, allowing the integration of batteries into these smaller but more active workboats →05. Onboard DC Grid is a modular power system platform that enables simple, flexible and functional integration of energy sources and loads, thus streamlining the design and build of power systems on all sizes of vessels. The platform is highly customizable so is easy to configure for the eWolf.
ABB Ability™ Marine Pilot family
Systems on board will also feature products from the ABB Ability Marine Pilot family for enhancing crew safety and reducing workload. For instance, ABB Ability Marine Pilot Vision provides an augmented view of the vessel’s surroundings by combining information from a range of sensors, resulting in enhanced situational awareness for the operator →06. This situational awareness solution will provide 360-degree visibility from the pilot’s station.
A second family member, ABB Ability Marine Pilot Control,will enable maneuvering support and future remote operations →07.
Marine Pilot Control is a new way to control vessels during all operational modes, including maneuvering, transit and position-keeping. Designed for autonomous and remote operations, the system enables optimal and complete all-speed vessel control from one operator position. Features include the potential to use the thruster control levers also as joysticks with ABB’s proprietary AX3 levers.
ABB Ability Marine Pilot Vision and ABB Ability Marine Pilot Control also ready the vessel for future remote control operations. ABB has experience of this mode of operation from similar projects in Asia Pacific and Europe, including delivery of highly automated, remote control-ready harbor tugs to the Port of Singapore . Increased levels of automation aid efficiency but also improve safety, which is of paramount importance.
The full scope of supply also includes propulsion motors, low-voltage switchboards, transformers, lithium-ion batteries, mechanical L-drive thrusters and the ABB Ability Remote Diagnostics System for Marine for continuous equipment monitoring and predictive maintenance.
Energy storage system
Tug operations can be demanding and often need to adapt to fast-changing load requirements. The eWolf’s batteries provide power to the propulsion system almost instantaneously, making ship-assist operations more efficient and eliminating the extra emissions resulting from sudden power demands in diesel motors. Based on a typical workday, the batteries need fast charging during the day and less intensive overnight charging.
The eWolf is being equipped with a 6.2 MWh Corvus Orca Energy battery – an essential part of the integrated electrical propulsion system delivered by ABB. Corvus Energy USA will supply this energy storage system and enable the eWolf to achieve around 63 metric tons of bollard pull, emissions-free.
Ergonomics and safety
The electrification concept also contributes to safety on board. For example, because the electric drive eliminates the traditional exhaust system, the captain has a 360-degree panorama from the pilothouse and an uninterrupted view of deck activity.
The introduction of the eWolf to the Port of San Diego will be a significant milestone in the diesel-to-electric transition of marine propulsion. The advantages of electric tugboats are numerous and it is expected that many other ports in the United States – and around the world – will be watching the introduction of the eWolf keenly, eager to upgrade their own tugboat fleets. The last word can be left to Vice President of Maritime at the Port of San Diego, Michael LaFleur: “San Diego is proud of our focus on blue and green technology. Our goal is to be a ‘Port of Firsts.’ Everyone is interested in what we are doing to bring about the transition from diesel to electric workboats, and this project allows them to see the tangible results, clearly demonstrating the advantages of the push to electrification.”
 International Transport Forum, “Reducing Shipping Greenhouse Gas Emissions.” Available: https:// www.itf-oecd.org/ sites/default/files/ docs/reducing- shipping-greenhouse-gas-emissions.pdf [Accessed: 29 March 2022.]
 “Autonomous controlled vessel operation with ABB Ability Marine Pilot,” ABB Review 1/2022, p. 13.