Benefits and technology behind Stena's battery power launch

Stena Line will use a self-contained energy storage system on the battery retrofit of Stena Jutlandica. Rebecca Moore got the lowdown from the company behind the system

Stena Line is retrofitting a ferry with a self-contained battery storage system that will boost its energy efficiency on a difficult trading route.

The batteries will be installed on Stena Jutlandica, which operates between Gothenburg and Frederikshavn, and will be used for port berthing operations by Q3 this year.

The battery project will start now and will be completed in stages, said Stena. In step one, battery power would be switched on for bow thrusters and manoeuvring when berthing in port. In step two, an extended battery operation will be connected to the propellers, meaning Stena Jutlandica can be operated on electricity for about 10 nautical miles, equal to the distance between Gothenburg and Vinga Lighthouse.

In step three, battery capacity will be further expanded and the vessel will operate about 50 nautical miles on electricity corresponding to the distance between Gothenburg and Frederikshavn.

The objective of accomplishing this in several steps is to test and gather knowledge about electrical operation along the way. If the project is successful, other vessels in Stena Line's fleet of 38 vessels may also be retrofitted with batteries.

Trident Maritime Systems (formerly Callenberg Technology Group) is providing the self-contained energy storage system on the battery retrofit.

The unit will be located on the weather deck and can supply up to 3,000 kW instantaneously and has an energy capacity of approximately 1,000 kWh.

The solution will contain all components required to be fully automated, including battery banks, converters, transformers and control systems. Peripheral equipment for safety, cooling and performance monitoring is also included to meet requirements from classification societies and authorities.

Trident Maritime Systems director of sales and marketing, electrical energy management Per-Erik Larsson told Passenger Ship Technology that using battery power was particularly helpful for Stena Jutlandica’s operating route.

In this case, he said the vessel power consumption for accommodation on board the vessel was typically 8-900 kW. “But if the vessel needs to run bow thrusters, this goes up to 2-3,000 kW. This is when batteries can provide the extra power. Otherwise, to store enough energy to cater for this, the operator needs to run the auxiliary engines on idle as a spinning reserve. “This creates wear and tear, a lot of emissions and increases fuel consumption.”

He said the batteries would normally be charged by shore power, but charging on a voyage was also an option. “If you run a genset on 800 kW, this is not efficient – the most efficient way is to run it at 80-90% of maximum capacity. In this way the surplus power can be used to charge the batteries.”

Mr Larsson said “If you optimise the size of batteries and components, there is no doubt that this is an economically viable solution for many ships, especially ones in narrow waters where you need to have a lot of extra power available.”

Mr Larsson highlighted the benefits of using the self-contained system. “There are some clear advantages of a containerised solution, it is modular and can be moved to other trades and vessels.”

It also means that the container can be prepared and tested on shore, making installation on the vessel quicker and easier, and simplifies maintenance.

Battery power countdown

Step 1