Case studies
What the Evidence Shows
The maritime wind energy sector has produced a small but instructive body of evidence. The Stena Jutlandica remains the most cited installation -- and the most analytically useful, because the gap between installed capacity and recorded savings is what reveals the true mechanism.
Stena Jutlandica
In 2011, Stena Line installed two small wind turbines on the Stena Jutlandica, a ferry operating between Gothenburg and Frederikshavn. The turbines had a combined rated capacity of 8 kW. Stena calculated fuel savings of 80 to 90 tonnes per year.
The arithmetic does not add up -- if it is attributed to electricity generation alone. Two turbines totalling 8 kW, running at 30% capacity factor across 6,500 hours, would generate approximately 15,600 kWh annually. At 0.295 kg/kWh diesel consumption, that is roughly 4.6 tonnes of fuel. The recorded saving was 80 to 90 tonnes -- roughly 18 times larger.
The only credible explanation is aerodynamic drag reduction through vortex disruption. The turbines, mounted at the superstructure edges, changed the airflow around the vessel in a way that reduced the resistance the propulsion system was working against. The fuel saving was a system-level effect -- not a generation calculation.
What this means for H Nordic
H Nordic turbines in the 50 to 100 kW range are an order of magnitude larger than the Stena Jutlandica units. They generate substantially more electricity directly -- that contribution alone, at 50 or 100 kW per unit, dwarfs the 4 kW per unit of the Stena installation.
But they also exert a proportionally greater effect on the vessel's aerodynamic envelope. A 100 kW VAWT has a rotor that is significantly larger in diameter and height than an 8 kW unit. The vortex disruption it creates -- and the consequent drag reduction -- scales with rotor size, not just with rated electrical output.
The fuel savings figures published in the H Nordic fuel savings model are based on direct electricity generation only, with aerodynamic drag reduction excluded. This is the conservative position. The Stena Jutlandica evidence suggests the actual savings will be materially higher.
In the pipeline
H Nordic is conducting vessel assessments with operators across the Baltic, North Sea, and Northern European ferry and cargo sectors. Reference installations from this pipeline will be published here as they progress to deployment.
Operators who wish to be considered as reference customers for published case studies are welcome to indicate this during the vessel assessment process. We will not publish any operator information without explicit written consent.
[Vessel operator TBC]
Assessment in progress -- details to be published on completion.
Your vessel
Early adopters in maritime wind energy have consistently found that the real-world savings exceed projections -- in part because the aerodynamic drag contribution is not captured in pre-installation models. Vessels that deploy early and document their performance carefully provide the most valuable evidence base for the sector.
H Nordic supports reference customers with detailed performance monitoring and reporting, and with the documentation required for funding applications and class society submissions.
If you are interested in being among the first operators to deploy H Nordic VAWTs and contributing to the growing evidence base for maritime wind energy, speak to us.
We will produce a preliminary fuel savings estimate based on your vessel type, route, and operating profile within five working days.
Request a vessel assessment See the fuel savings model