Image: VardIn the Ocean Charger project, scientists from the Norwegian organisation Selskapet for Industriell og Teknisk Forskning (SINTEF) and engineers from the shipbuilding company Vard are developing a solution to charge battery-electric ships at sea without needing connecting cables with wireless charging, also called inductive charging. This approach aims to enable charging even in challenging conditions where cable-based charging is not feasible—such as in rough seas.The Norwegian developers have a specific application in mind: using service operation vessels (SOVs), maintenance technicians travel to offshore wind farms to carry out servicing work and transport the necessary materials. These SOVs are increasingly equipped with battery-electric powertrains. To extend their operational range and reach wind farms far from the coast, recharging the vessels’ batteries at the wind farm while technicians work would be highly beneficial.Conventional mechanical plug connections can struggle in such environments. The inevitable corrosion caused by salty, humid air can be mitigated with protective covers, but not entirely prevented. This leads to higher long-term maintenance costs. Additionally, the charging connection must be secure enough to prevent cables and plugs from being damaged or loosened in heavy seas. To address these challenges, the Norwegian partners aim to eliminate plug connections altogether and instead transmit charging power inductively.Mechanical connection, but inductive transmissionWhile the SINTEF solution still involves a mechanical connection between components, it does not require direct contact between the current-carrying parts. The developers compare the connection to a “cup holder into which a cup is placed.” The advantage is that the coils used to transmit power via a magnetic field are fully encapsulated on both the transmitter and receiver sides, protecting them from the elements and saltwater. This prevents corrosion, reduces maintenance requirements, and if the connection is disrupted due to rough seas, the contacts stay enclosed and protected from impacts and damage.“We’ve looked at a lot of solutions here, says Giuseppe Guidi, a senior research scientist at SINTEF. “And we’ve tested a possible solution that works almost like a regular electrical contact. But we can avoid all the problems because we transfer the power inductively by encapsulating the plug itself in materials that can withstand just about anything.”The solution is still in the laboratory development phase, so its performance metrics are not yet sufficient for large ship batteries, but the prototype developed by SINTEF and Vard can already transmit 50 kW of power inductively. In the future, the system is expected to be fifty times more powerful than the laboratory prototype. Instead of manual handling, the connection will be established using a crane-like boom, capable of transmitting up to five megawatts.If such a solution becomes established at sea, other types of offshore platforms, such as oil and gas rigs, could also increasingly adopt electric propulsion and recharge at the platforms.heise.de, sintef.no