H Nordic maritime turbines have no cut-out wind speed. In high winds -- the conditions that force conventional turbines to shut down and feather their blades -- H Nordic turbines continue generating at rated output without mechanical intervention or software override. This is a design characteristic, not a control strategy. The rotor geometry is inherently self-limiting.
Horizontal axis wind turbines (HAWTs) have a cut-out wind speed -- typically around 25 m/s (Beaufort 10, storm force) -- above which they shut down. The blades are pitched to feather position, the rotor decelerates, and generation stops until the wind drops back below the restart threshold.
This shutdown is necessary because HAWT blades operating at high tip speeds generate aerodynamic forces that increase as the square of wind speed. Above cut-out, the structural loads on the blades, hub, and tower exceed safe design limits. The turbine must stop to protect itself.
At the cut-out threshold of 25 m/s, the turbine goes from full rated output to zero output in a matter of seconds. For a vessel in severe conditions -- precisely when generator load is highest and fuel consumption is at its peak -- the turbine that was contributing to onboard power simply stops.
H Nordic turbines use a vertical axis rotor geometry that responds differently to increasing wind speed. As wind speed rises above rated, the aerodynamic conditions on the rotor blades change in a way that naturally limits the rotational speed and the forces on the structure -- without any mechanical braking or blade pitch adjustment.
This is not a software response. There is no control system that detects high wind and commands the turbine to reduce output. The physical geometry of the rotor produces the self-limiting behaviour directly. It is the same principle at work at 2 m/s and at 40 m/s -- the rotor responds proportionally to the aerodynamic forces it experiences.
The practical consequence is that there is no cut-out wind speed. The turbine continues generating through conditions that would force a HAWT into shutdown. In a Force 10 storm, the H Nordic turbine is still producing its rated output -- delivering electricity to the battery when the vessel's fuel consumption and generator load are at their highest.
Rated output means the turbine's nameplate power: 50 kW or 100 kW depending on the model. Above the rated wind speed, the self-limiting geometry prevents output from rising further -- the turbine does not overproduce, it maintains. Below rated wind speed, output rises with wind speed following the power curve.
On a vessel in storm conditions with wind speeds well above rated, the turbine is at its maximum continuous output. The electricity is being produced at the point in the voyage when it is most valuable -- reducing generator load, reducing fuel consumption, at exactly the moment when those costs are highest.
Generating continuously in heavy weather requires a structure designed for the forces involved. H Nordic maritime turbines are designed and tested for open ocean conditions. Structural loads are calculated for the combined effect of high wind speed, vessel motion (pitch, roll, and heave), and wave-induced vibration -- the full maritime load envelope, not land-turbine conditions.
The mounting structure is designed to accommodate these loads, and the structural assessment conducted for each installation confirms that the deck positions selected can withstand them at the specific vessel's motion characteristics.
The integrated battery storage -- 215 kWh for the 50 kW model, 430 kWh for the 100 kW model -- means that even if vessel electrical load is low during the storm passage, generated energy is captured and stored rather than wasted. As the vessel manoeuvres, slows, or operates auxiliary systems in demanding conditions, the battery provides the buffered output smoothly without generator intervention.
See also: How the venturi effect works on vessels · Turbine maintenance
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