BOS Power has been awarded a turnkey Battery Energy Storage System (BESS) contract covering two coastal sites, in the harbours of Aarhus and on Sjællands Odde. Each battery pack will have a capacity of 118 MWh and will ensure the large catamarans can recharge every time they berth at one of the two ports. The contract adds almost 250 MWh of energy storage to BOS Power's Nordic portfolio, which now exceeds 500 MWh of delivered and contracted capacity, and ranks among the largest energy storage projects in the company's history.

Charging will take place over roughly half an hour using a combination of grid power and the harbour batteries. When a single catamaran connects to the charging point, the vessel will charge at 15 kV AC and 55,000 kW for 30 minutes, equivalent to an average of 25,000 kWh of energy received before the next crossing. The onshore batteries provide backup and redundancy, storing the equivalent of three to four ferry crossings should grid supply falter.

"We cannot simply charge directly from the supply grid on every crossing. To be certain of always having the necessary energy available, we need the batteries for backup and redundancy," said Carsten Jensen, CEO of Molslinjen. Hans-Henrik Simonsen, Technical Director at Molslinjen, added that the large onshore battery systems will be central to the transition of the high-speed ferries to electric operation.

BOS Power will act as full EPC contractor and turnkey system integrator across both sites, carrying the complete scope under a single point of responsibility, from design, engineering and permitting through civil works, mechanical and electrical installation, commissioning and grid code compliance. The integration of both installations directly into the port and charging infrastructure makes the project one of the more technically demanding BESS deployments in the Nordic region.

"This ferry route is critical infrastructure. The Kattegat connection between Jutland and Zealand is a lifeline for the people and goods that rely on it every day, and electrifying the ferries that serve it has to be done without compromising that reliability," said Kim Strate Kiegstad, Head of Energy Storage at BOS Power. The work has been carried out in cooperation with experts from Hybrid Greentech, which has advised Molslinjen since the project began.

The three battery-powered catamarans are currently under construction at the Incat yard in Australia, with the first ferry scheduled to enter service in spring 2028. Once all three vessels are in operation, the project is expected to save 132,000 tonnes of CO2 each year. The ferries and associated onshore infrastructure carry a total cost of DKK 3.5 billion, while the parties have agreed not to disclose the price of the two battery packs.