Damen Shipyards plans to build a fleet of battery-powered electric tugs for green harbour operations, with first deliveries scheduled for early 2024. 

These will be reverse stern drive (RSD) tugs with Toshiba batteries to provide power to L-drive thrusters for zero-emissions towage, with Caterpillar generator sets for redundancy and long-distance voyages. 

They will be built at Damen Song Cam shipyard in Vietnam, where the first battery-powered harbour tugboat Sparky was completed and commissioned in 2022. 

Damen Shipyards product manager for tugs Erik van Schaik says the first of these RSD-E tugs will be ready Q1 2024 and two more are likely to be completed during H1 2024.

Another three RSD-E tugs could be built ready for delivery H2 2024. Damen will design and build these tugs on a speculative basis and seek buyers or work in partnership with owners. 

These battery-powered tugs will be built to Damen’s RSD-E 2513 design with an overall length of around 25 m, a beam of 13 m and depth of 5 m, with a bollard pull of 70 tonnes and speed of 12 knots. 

These will be similar to Sparky, which started operations in Auckland, New Zealand June 2022 and has operated since almost completely on batteries. 

This tugboat has 2,240 Toshiba batteries, an Echandia Marine battery management system, a Praxis centralised alarm, monitoring and control system and Damen Triton remote monitoring system. Battery charging takes around two hours from empty to full using four high-power cables of 375 kW capacity each. 

Sparky has two C32 engines to provide back-up power through a generator, which can step in if the battery charge is low. These generate 1,175 kW at 690 V and 60 Hz to provide a power boost, run fire-fighting systems and charge the batteries if required. A Damen selective catalytic reduction system is installed to minimise NOx emissions for IMO Tier III compliance. All this drives two Kongsberg Maritime US 255 L-drives. 

“We used automotive industry cables for high-power charging and to ensure one person can operate the charging station and loading arm,” said Mr van Schaik during the European Tugowners Association conference, in February in Brussels, Belgium. 

Sparky can do all operations on batteries with very little support from the gensets. 

“Sparky can do three to four jobs per day and sometimes five jobs,” says Mr van Schaik. “The back-up gensets are not used.”  

This has saved 75 tonnes of CO2-equivalent emissions compared with all-diesel operations. “Electric costs are 35-40% of diesel costs for an ASD 2411 tug and downtime is minimal,” he says. 

Damen’s Triton monitoring and analytics platform captures data from tugs, stores it in a gateway on the vessel and sends it to a cloud storage facility, where the owner can access the information and share it with Damen. 

“We are using data to compare electric vessels versus diesel-powered vessels and to advise on the options to optimise operations and sustainability,” says Mr van Schaik.

For longer distance towage operations, Damen has designed methanol-powered tugs with azimuth stern drive (ASD) propulsion. It anticipates high demand for ASD-M 2412, ASD-M 2613, ASD-M 2714 tugs with methanol fuel for coastal towage and terminal operations. Damen is also considering building ASD-E 1810 and ASD-E 2111 tugs with batteries for harbour towage. These feature two sets of batteries at the fore, two L-drive thrusters at the aft with the gensets or engines at midship. In the longer term, there may be Damen-designed and built tugs with hydrogen fuel cells or using other alternative fuels.

Source: Riviera 

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	Issue 83 of Robban Assafina (Jan./ Feb. 2023)