Svitzer Balder swaps methanol gensets for diesel as world-first tug scales back

What changed

Svitzer’s Balder, promoted as the world’s first battery-electric methanol tug, has had its methanol gensets removed and replaced with additional diesel range-extender engines. The decision comes after the vessel was delivered in the second half of 2025 following a September 2024 contract with Turkish shipyard Uzmar.

“After comprehensive testing and review, we have decided to remove the methanol engines and replace them with additional range-extender engines,” Thomas Grondorf, head of Communications at Svitzer, told Maritime Journal. “The methanol gensets had technical difficulties and performance uncertainties. At Svitzer, we need reliable and durable technical solutions to serve our customers.”

Grondorf declined to give further detail on what those technical difficulties and performance uncertainties were.

The setup today

The tug remains notable for its battery pack, not its gensets. “Svitzer Balder remains the largest battery-driven escort tug, featuring a 6,000-kWh battery, but is now powered by three range-extender diesel engines generating 2,700 kWh,” Grondorf said.

The vessel was built on the Robert Allan TRAnsverse design, originally specified with a 6 MWh battery “supported by dual-fuel methanol engines for back-up and range extension.” Uzmar called it “a massive leap toward environmental friendly maritime operations” when nominating the tug for this year’s International Tug & Salvage awards.

Svitzer expects around 90 percent of the tug’s operations to be carried out on the battery-electric powertrain, according to Grondorf, meaning the diesel gensets act primarily as top-up range extenders rather than the primary drive source.

Still methanol-ready

The removal is not permanent by design. Grondorf framed the change as a course correction within an innovation project.

“Svitzer Balder was initially an innovation project aimed at creating a battery-powered TRAnsverse escort tug, equipped with both methanol and diesel range-extender engines,” he said. “As expected with innovation, our understanding improved over time. Balder is still methanol-ready, meaning we can reinstall the methanol gensets once the technical solution’s performance is proven.”

That caveat matters for anyone tracking the methanol transition on the water. The hardware pathway is not closed off, but Svitzer has clearly decided that a diesel range extender is the dependable option for serving customers today.

The wider methanol picture

This setback lands against a sobering backdrop for methanol propulsion. The number of methanol-powered tugs can still be counted on one hand, and not all of those are strictly operational.

The most relevant counterpoint is Methatug, which has operated at the Port of Antwerp-Bruges since May 2024 under the European Fastwater Project, aimed at demonstrating methanol’s feasibility as a sustainable marine fuel.

“Methatug is still operating in our port,” spokesman Tom Cuypers told Maritime Journal. “As with any pilot project, we have encountered some technical challenges along the way, but these are to be expected in an innovative development project. And it means that, together with our partners, we are gaining valuable insights about this technology for the future.”

Cuypers noted a structural difference between the two vessels. Methatug converted the engines of an existing tug into dual-fuel units rather than building new, and carries no batteries aboard. Its tug performance with traditional diesel remained the same, he said.

What to make of it

For operators watching alternative fuels as a signal rather than a product, the Balder news is a mixed read. The battery side of the design is intact, and a 6,000-kWh pack on an escort tug still represents a serious electric propulsion commitment. The methanol side, however, has been parked until the technology proves out in service.

The honest caveat is that “methanol-ready” is not the same as “methanol-powered.” The gensets coming out are real, the technical difficulties were real enough to force the swap, and Svitzer has not named a timeline for reinstalling them. That is the difference between a demonstration project and a customer-facing workboat.