It’s been two years since marine operators Crowley Shipping placed an order with Master Boat Builders. However, this time it was not for another diesel container ship, roll-on roll-off vessel, or multipurpose tugboat / barge. They wanted to acquire the first U.S. electric powered harbor tugboat. Two years later, Auto Evolution reports the eWolf all-electric tug is doing its San Diego sea trials.
Serious Power Behind the eWolf All-Electric Tug
Corvus Energy announced it would supply the energy storage system for the eWolf, on August 30, 2021. This would include its 6.2 megawatt-hour Orca Energy battery, to power the propulsion system.
WorkBoat picked up the threads again on May 29, 2023, when it revealed intriguing ideas to resolve the ‘lack of charging infrastructure’:
- Power buoys for charging at offshore wind sites could be adapted for anchorage applications.
- This option could also provide shore power to vessels awaiting their next voyage instructions.
More Info About the Crowley Shipping eTug Battery
The Orca Energy lithium-ion battery uses lithium-nickel-manganese-cobalt, and graphite electrodes. Passive safety systems on the eWolf all-electric tug include single-cell thermal-runaway isolation, so overheating does not spread across to adjacent cells.
Performance Credits for the eWolf All-Electric
Crowley Shipping predicts significant sustainability-savings, during the first 10 years of operation. These benefits will include the following, when compared with the current tugboat consuming more than 30,000 gallons of diesel per year:
- The new eTug will save 178 tons of nitrogen oxide, 2.5 tons of diesel particulate matter, and 3,100 metric tons of carbon dioxide over the first decade.
The 82-foot electric vessel undergoing trials boasts 70 tons of bollard pull, or force exerted under full power on a shore-mounted bollard, through a tow-line.
The eWolf all-electric tug is a joint venture involving San Diego County Air Pollution Control District, California Air Resources Board, Port of San Diego, U.S. Environmental Protection Agency, and U.S. Maritime Administration.
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