Wartsila hybrid propulsion systems for three ropax ferries being built for Stena RoRo will be the largest to date — about double the size of those in typical use today.

Two of the ferries will have a battery capacity of 11.5 MWh, making them the largest hybrid vessels to date, Stena said.

The vessels, which will be chartered by Brittany Ferries, will be equipped with the latest-generation Leclanche Navius MRS-3 energy storage systems, which Wartsila said have size and weight advantages over comparable marine batteries.