Improving the performance of Vertical Axis Wind Turbines (VAWTs) has been on the 'to do list' for many years. Vertical axis turbines have blades that are vertical and travel around a central axis. SuperVAWT's technology provides the upgrade in performance that the design has been waiting for. By controlling a blade that has a flap on the trailing edge. These are much the same as ailerons or flaps on aircraft which can rotate to control the amount of lift but ultimately allows you to increase the lift. The technology increases efficiency and lets you control the power of the blade in strong winds. Flaps can increase drag but we know that the net tangential lift is higher. This basic principle is evident from sailing but the performance has been validated by computational fluid dynamics measuring every angle and position around a rotation. Just as importantly, you can reduce the power from the turbine to zero or even stall the turbine aerodynamically to stop it. Wind power is one of the great success stories of renewable power and has managed to reduce costs so successfully that it can produce power for less than the wholesale price of electricity.
At small scale, vertical axis wind turbine designs can have very high rpms which puts large forces on the vertical blades. Vertical axis designs using SuperVAWT technology have low solidity, they have a low blade area to swept area, so the blades look thin, this makes them difficult to build at small scale without expensive composite materials. As the turbines scale up, these centrifical forces reduce quickly, so that at MW scale they are not important in terms of the structural design of the blades. This makes VAWTs using superVAWT technology a low-cost technology at MW scale.
Certainly, historical designs of VAWTs when tested have shown a 15-20% lower efficiency. In addition, they often lacked aerodynamic controls which are very important when the power in the wind has exceeded the power of the wind turbine's generator. SuperVAWT technology, is by its nature an upgrade to vertical axis technology that increases power capture but it can also be used to reduce power too.
Horizontal axis turbines have the generator at the centre of the rotor. These generators are very heavy and are over a hundred metres above the floating platform. Vertical axis turbines by contrast, have their generators under the turbine. This much lower vertical centre of gravity, reduces the cost of the floating platform and makes a floating wind turbine using a VAWT more stable.
A 9.5MW turbine, using SuperVAWT blade control technology, would reduce the cost of floating wind by between 30-40% over and above any cost savings achievable by installing conventional floating horizontal axis turbines. In addition, the turbines would be safer to tow, install and operate.
SuperVAWT is patented and increases wind turbine performance by 20-25% over conventional horizontal axis wind turbines. This equates to a 55-60% increase over the historic vertical axis wind turbine designs, whether fixed or variable pitch, which have been tested in the past.
A 20MW wind turbine using SuperVAWT technology, would reduce the cost of energy from floating wind turbines by 50-75% (we don't know exactly how reliable floating HAWTs are going to be in the long term). Larger turbines reduce the costs of installation and maintenance and are quicker to build and install. It has been known since the 1980s that vertical axis turbines could be built to 20MW scale and that is why they remained of interest to wind turbine experts. A more recent study put the limit at 30MW for a straight bladed H rotor vertical axis wind turbine design.
20MW horizontal axis turbines are not expected before 2038. The tip speed of HAWTs creates increasing problems with scale because the tip of the blade is travelling much faster than the middle or centre of the blade. Vertical axis turbine designs using a superVAWT design have blades where the whole blade travels at the same speed. Though you may like to note that the vertical axis egg beater design, did have different sectional blade speeds. Another problem for HAWTS, is that today's horizontal axis turbines at 8-15MW have not been designed for the increased loads on floating platforms and are at an early stage of deployment and evaluation on fixed foundations. So, a floating horizontal axis turbine at 20MW scale is probably at least 20 years away. By contrast, because VAWTs can be built to a bigger scale than HAWTs, a 20MW floating Vertical Axis Wind Turbine could be certified and wind farm ready by 2028. In terms of technology readiness level, for floating, superVAWTs have the highest TRL at 20MW by over a decade.
Using VAWTS with superVAWT technology may also have other positive environmental benefits beyond reducing the cost of renewable energy. It is expected that the whole blade can be made from fully recyclable materials. This is could solve at a stroke, the largest problem the wind energy business faces today.
An efficient use of the sea will reduce the cumulative impact on shipping, fishing and radar. 20MW turbines using the SuperVAWT technology can produce 60% more power for the same area of seabed as 9.5MW turbines. For countries with a limited area of seabed available for wind farm development, this significantly increases the renewable generating power that they can achieve.To the top
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