Video: Crowley's All-Electric Tug is Out on Sea Trials

America's first all-electric tug is out on sea trials, according to shipowner Crowley. 

The electrically-powered eWolf was designed by Crowley's engineering team for a ship-assist application, and was built by Master Boat Builders of Coden, Alabama. With twin drives from Schottel, it will have a bollard pull of about 70 short tonnes. 

The eWolf has six megawatt-hours of energy storage, enough for the vessel to operate for a full day. For backup and longer transits, it has two generators on board. When compared with the tug it is replacing, it will eliminate the combustion of 30,000 gallons of diesel per year. 

The tug will be based at the Port of San Diego’s Tenth Avenue Marine Terminal, where Crowley is building a dedicated charging station. The station will have twin battery banks, which will charge up from solar panels during the day and the utility grid during the nighttime, when the public demand for power is lower. When the tug pulls alongside to recharge, the batteries on the pier will transfer their accumulated power to the batteries on the tug.

Crowley partnered with the San Diego County Air Pollution Control District, the California Air Resources Board, the Port of San Diego, the U.S. EPA and the U.S Maritime Administration to get the project across the finish line. 

“Crowley is on a mission to become the most sustainable and innovative maritime and logistics company in the Americas,” said Tom Crowley, the firm's chairman and CEO, in a statement at the tug's keel laying. “Working together with our customers, suppliers, policymakers and others across our value chain, we can meet the climate crisis head on.”