On Wednesday 13 September, PortLiner signed a contract with the Port of Rotterdam Authority for the berth of the charging and storage pontoon that PortLiner is preparing. This is a pontoon where electrolyte will be charged with electricity to supply power to electric barges with flow batteries.

About two years ago, PortLiner started the project together with Greenchoice and Vattenfall to realise an emission-free charging and storage pontoon in the Hartelkanaal. By May 2023, PortLiner had already received the Environmental Permit from the Municipality of Rotterdam and the Environmental Department Rijnmond (DCMR).

With the berth contract now signed, PortLiner, together with the Port of Rotterdam Authority, has taken the next important step and PortLiner can further prepare the construction of the pontoon and the first electric ships.

Also read: PortLiner to develop flow battery bunker station with wind turbines

Maritime flow battery

PortLiner’s electric ships will be equipped with flow batteries, a long-established technology that is now being used in shipping for the first time. Lloyd’s Register has given approval for the application of this technology in inland shipping and has now also promised emission label A, which means PortLiner’s future vessels will also be formally “zero emission”.

In flow batteries, electrical energy is stored in a liquid electrolyte. On board the ship, positive and negative electrolyte is passed along stacks (conversion cells), allowing electricity to be absorbed and released.

The electrolyte is a fixed quantity that can be reused time and again. Thus, after use, the empty (discharged) electrolyte can be exchanged on a charging and storage pontoon. In time, new electrolyte can also be “refuelled” at a special electrolyte bunker barge.

Also read: PortLiner to build two zero-emission inland ships


The berth of the charging and storage pontoon is in the Hartelkanaal, near the wind farm of Greenchoice, one of the partners in the project. The pontoon will take power from the eight wind turbines there, guaranteeing a continuous supply of green energy.

The location on the Hartelkanaal canal in Europoort is an important crossroads of shipping routes. A central spot in north-western Europe, where the bulk of container ships pass, sailing from Rotterdam to Antwerp or Germany and from the Maasvlakte to Amsterdam.

With the berth contract now signed, PortLiner has a great basis to give the concept of maritime flow batteries a good start. PortLiner and its partners look forward to a good cooperation with the Port of Rotterdam Authority in the coming years.

Picture by PortLiner.

Also read: CellCube and Portliner to build flow battery solution for all-electric inland vessel