In a world first, an inland cargo vessel is capable of “hybrid sailing” with solar power. The Blue Marlin is equipped with over 190 solar panels. Dutch maritime solar innovator Wattlab developed a solar energy system, marking a major sustainability milestone for the industry.

Solar-Powered Hybrid Vessel

Wattlab collaborated with European inland waterway shipping giant HGK Shipping to develop the solar system. However, this isn’t the companies’ first solar endeavor. In 2024, HGK’s MS Helios made it into the Guinness Book of Records for having the largest solar panel installation on an inland shipping vessel. According to the company, it had a total of 312 panels.

However, the company says the Blue Marlin takes the technology a step further.

The Blue Marlin has a more advanced system compared to the Helios, which used solar energy exclusively for low-voltage onboard systems. “The Blue Marlin’s 192 solar panels are not only connected to the low-voltage onboard systems but also to the high-voltage propulsion network,” Wattlab co-founder and COO David Kester said. “This means that HGK Shipping can proudly state that they are the first inland shipping company to operate a vessel that uses solar power directly for propulsion.”

Under optimal conditions, Blue Marlin’s solar power system delivers up to 35 kilowatts. It works together with four diesel generators, the Wattlab team says. By integrating the dieseal generators and solar systems, it allows peak shaving. Solar energy and batteries prevent the need for another generator during periods of high demand.

Making a  Sustainable Industry, More Sustainable

Additionally, the system has an energy management system to ensure efficient energy distribution, which reduces fuel consumption. “In situations where the ship is lightly loaded and travelling downstream, we anticipate that it may even sail using only solar power for limited periods,” Kester said. “An unprecedented achievement in the inland shipping sector.”

Tim Gödde, Director Ship Management at HGK Ship Management Lux S.à r.l., expressed how the innovative system adds to the already sustainable mode of transportation. “The Blue Marlin now goes one step further by also using solar energy for the power train,” he said. “It makes another important contribution to making shipping, which is already a low-emission mode of transport, even more sustainable.”

Furthermore, researchers added how efficient the installation process was. They said it took about a week to install the panels and a few days for commissioning.

“Considering a similar-sized retrofit project, we estimate that a shipowner would be looking at a downtime of no more than one week,” Kester concluded.