Dutch solar innovator Wattlab and German inland shipping giant HGK Shipping have unveiled the world’s first inland vessel capable of using solar power for propulsion. The newly delivered Blue Marlin represents a major step forward in hybrid marine technology, showcasing how solar energy can be integrated not only for onboard systems but also for driving high-voltage propulsion.
The 192 solar panels installed aboard the Blue Marlin will supply power to both the hotel load and the vessel’s electric drive system—making it the first inland cargo ship globally to achieve this level of hybrid capability. Under optimal conditions, the panels can generate up to 35 kW, enough to support the propulsion system directly. The solar setup works in tandem with four diesel generators, allowing for peak shaving—a feature that prevents the need to activate additional generators during high energy demand, thus reducing fuel consumption and emissions.
The Blue Marlin’s solar system includes an automated energy management platform that smartly distributes electrical power across systems, maximising efficiency and fuel savings. The vessel is also capable of limited all-solar sailing—especially when lightly loaded and travelling downstream.
This isn’t HGK’s first solar venture. In 2024, Wattlab and HGK partnered on the MS Helios, a 135 m dry cargo vessel that entered the Guinness Book of Records for having the largest solar array on an inland ship, with 312 panels. However, unlike the Blue Marlin, the Helios’s solar system powers only low-voltage onboard systems.
