The MV Vertom Tula marks a major maritime milestone as the first seagoing vessel to deploy Wattlab’s Solar Flatrack technology, utilizing 44 modular units to offset 20% of its onboard hotel load. This scalable, “plug-and-play” system integrates with standard container fittings, allowing for rapid installation and stackable storage that preserves cargo flexibility. Validated by TNO and nominated for international awards, the project demonstrates a commercially viable path for short-sea shipping to meet tightening FuelEU Maritime and EU ETS emissions standards.
Rotterdam | Jan 5, 2026 – In a move that signals a maturation of solar technology within the short-sea shipping sector, Dutch innovator Wattlab has recently commissioned its first full-scale Solar Flatrack installation aboard the MV Vertom Tula.
The delivery marks a pivotal transition for Vertom, a global maritime services provider with a fleet of over 100 vessels. After three years of rigorous pilot testing, the company has moved beyond experimentation, outfitting the 7,280 DWT diesel-electric multipurpose vessel with 79 kWp of solar capacity, the first seagoing coaster to utilize this specific modular configuration.
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Engineering for the “Hotel Load”
The installation comprises 44 Solar Flatracks, engineered to integrate seamlessly into the vessel’s existing infrastructure. According to Wattlab, the system is designed to offset approximately 20% of the vessel’s “hotel load”, the electricity required for onboard systems, climate control, and crew facilities.
By targeting the hotel load, the system provides a consistent reduction in auxiliary engine run-time, directly translating to lower fuel consumption and a reduction in GHG emissions. For shipowners navigating the complexities of FuelEU Maritime and the EU ETS, such incremental gains are becoming essential components of a broader decarbonization strategy.
“Space is Money”: The Modular Advantage
One of the primary hurdles for maritime solar has been the “interference” factor, the risk that fixed panels might obstruct cargo operations. Wattlab’s solution addresses this through a “plug-and-play” design:
- Rapid Deployment: The 44 units were installed in the Port of Harlingen in under 24 hours.
- Twist Lock Integration: The units utilize standard container twist lock fittings, allowing them to be secured or removed with the same equipment used for standard 20ft containers.
- Stackability: “Should the panels need to be removed to make way for a special type of cargo, the crew can easily stack and store them all on the footprint of one 20ft container,” says Bo Salet, co-founder and CEO of Wattlab.
“For shipowners, time is money, so speed and ease of use are important. Furthermore, we know that ‘space is money’ too.” — Bo Salet, CEO of Wattlab
Performance in Harsh Conditions
The maritime environment is notoriously hostile to photovoltaics, citing salt crusting and physical vibration as major points of failure. However, Thomas van Meerkerk, Business Development Manager at Vertom, noted that the system has already proven its resilience during pilot phases.
The panels are designed to remain on hatch covers during loading and discharging, featuring a drainage system that prevents the accumulation of salt and grime. TNO, the Dutch independent research organization, has validated the system’s ROI and emission reduction data, with a formal report expected to be published shortly.
Market Context: The Rise of Wind and Solar
As the industry eyes the 2030 IMO targets, the Vertom Tula represents a growing trend of “hybridization” in the short-sea segment. While primary propulsion remains diesel-electric, the addition of 79 kWp of solar provides a layer of energy resilience against volatile fuel prices.
The project, co-financed by the EU’s Just Transition Fund (JTF), has already gained international traction, earning nominations for the Environmental Protection Award and Bulk Ship of the Year at the upcoming IBJ Awards.
The Bottom Line: For the maritime and energy sectors, the Vertom Tula is a case study in how modular renewable tech can be retrofitted without disrupting traditional port operations or sacrificing deck flexibility.
From Student Room to the Record Books: The Wattlab Story
The maritime industry is famously tough on technology, but Rotterdam-based Wattlab has proven that solar isn’t just for rooftops anymore. Founded in 2017 by three Delft University students, Bo Salet (Aerospace Engineering), David Kester (Electrical Engineering), and Siebe Roefs (Applied Physics), the company has rapidly evolved from a “student-room startup” into a global pioneer of maritime-grade photovoltaics.
Born from the Nuon Solar Team (winners of the World Solar Challenge), the founders applied their high-performance solar car expertise to the shipping world. Their core insight? Standard solar panels are too heavy and fragile for the sea. Wattlab’s solution was to integrate ultra-thin, lightweight panels into the very fabric of the vessel, starting with hatch covers.
A Portfolio of Pioneers
Wattlab’s trajectory has been defined by “world-first” milestones that bridge the gap between inland waterways and the open ocean:
1. The Guinness World Record: MS Helios
In September 2024, the MS Helios, a 135-meter dry cargo vessel operated by HGK Shipping, officially entered the Guinness Book of Records. It features the world’s largest solar panel installation on an inland shipping vessel, boasting 312 solar panels across 27 hatch covers. The system generates roughly 90 MWh annually, saving approximately 90 tonnes of CO2 per year.
2. Hybrid Propulsion: Blue Marlin
Building on the Helios success, Wattlab partnered again with HGK to deliver the Blue Marlin in 2025. While previous vessels used solar solely for the “hotel load” (onboard systems), the Blue Marlin is the first inland vessel capable of hybrid propulsion, where solar energy feeds directly into the high-voltage powertrain to assist the diesel-electric engines.
3. Seagoing Scalability: Solar Flatrack
Wattlab’s most recent breakthrough, the Solar Flatrack, takes the technology to the high seas. Designed for coasters and bulkers, these units use standard container twist locks for “plug-and-play” installation. Following the landmark installation on the Vertom Tula, the company is now scaling these solutions for Supramax, Panamax, and Capesize vessels.
Innovation Built for the Crew
Wattlab’s philosophy is grounded in operational reality. Their systems are designed to ensure:
- Zero Interference: Panels remain on hatches during loading/unloading.
- Modular Flexibility: If a vessel carries specialized deck cargo, the Flatracks can be stacked and stored within the footprint of a single 20ft container.
- Durability: Engineered to prevent salt-crust formation and withstand the mechanical stresses of a working cargo deck.
“We are born engineers, and our expertise lies in robust solutions suitable for every ship. We believe in making the world a cleaner place, one solar panel at a time.” – The Wattlab Team
With over 30 commercial projects active and a growing list of international partners, Wattlab is no longer just “testing the waters.” They are actively rewriting the energy profile of the global fleet.
Source: Wattlab