Propulsion specialist Voith will deliver eight electric Voith Schneider Propellers (eVSP) to the Norwegian shipping company Østensjø, thus enabling resource-saving and energy-efficient operation of the four offshore wind supply vessels. The four ships will be built in Spain and are already equipped for the application of CO2-neutral hydrogen technology. Among the advantages of the new eVSP are, in particular, the high efficiency and reduction of complexity, as the permanent-magnet synchronous motor is already integrated in the propeller.
In addition, the best possible manoeuvring performance is a decisive factor for use in the offshore wind industry. Accurate dynamic positioning (DP) even under harsh environmental conditions, very fast starting and leaving of the wind turbines, and a safe and quick transfer in the offshore wind farm are critical factors for smooth operation.
Comparative calculations have shown that a VSP-driven ship can manoeuvre safely at significantly higher wave heights, thus offering the operator an economic advantage. Due to the very fast and accurate thrust adjustment, the VSP can reduce the rolling motions of the ship by up to 70 percent, both when the ship is moving and when it is stationary at the wind turbine.
The electric Voith Schneider Propellers are also characterized by very high efficiency and are optimally integrated into the ship’s design. In model tests with ducted screw propellers, an average advantage of 15% for the eVSP was measured with regard to power requirements in transit. The electric version of the VSP is also characterized by lower fuel consumption in dynamic positioning because it acts very quickly against disturbing wind, wave and flow forces.
The eVSP is a new development of the Voith technology group. With this new type of gearless propeller, the permanent-magnet synchronous motor is directly integrated into the VSP. The drive system combines the technology of the VSP with more than a decade of electrical know-how of the Voith Inline Thruster (VIT). Voith claims the advantages of the eVSP are an increase in efficiency due to the elimination of gears and the reduction of bearing points, as well as a very high motor efficiency, also in the partial load range, which is particularly relevant in the offshore sector. In addition, no separate electric motor is required and shaft lines are also eliminated.