Two Danish wind energy companies have in cooperation with the Technical University of Denmark and wind energy cluster Hub North developed a system to improve the performance of wind turbines – PowerCurve. It consists of a series of quite simple, specially designed plastic components installed on the turbine blade from base to tip.
However, this is where the simplicity ends. The shape of the plastic components exploit known natural forces such as aerodynamics, an area in which Denmark has some of the world’s leading scientists. The product is based on the concept of so-called vortex generators, whose purpose is to draw the wind closer to the turbine blade, thereby transferring more power to it.
“The technology has previously been used for quite different purposes such as making fluids go through pipes faster and in WW1 fighter planes. We are now using the same natural forces to increase the energy that makes the turbine blade spin. This can have a huge effect on the turbine owner’s profit, on reducing the cost of energy and on society as a whole,” says Per Henriksen, CSO at PowerCurve in Aalborg, Denmark.
Through the company Sander Tech, Per Henriksen has been a supplier to the wind turbine industry for more than 15 years, and many turbines made in Denmark already use vortex generators. Typically, the turbine blade will have a number of plastic components in different sizes installed end-to-end, from root to tip. The plastic components are smallest near the tip of the blade.
Researchers in aerodynamics from the Technical University of Denmark have performed complex calculations of exactly how these plastic components should be shaped on individual turbines depending on size and type.
“The precise shape and placement of the components on the blade determine the effect, which can be an increase in performance of up to as much as 10%. At the same time, it is important to note that the effect of the plastic components is increased over time,” says Per Henriksen.
Blades are wear components. They become warped and the surface gets rougher as the turbine ages. Vortex generator can prolong the turbine’s lifetime. In other words: on old turbine blades, vortex generators are very efficient.
PowerCurve’s product is being tested on two sites belonging to some of the world’s largest energy companies. The tests will show how much more power, turbines can produce using PowerCurve’s vortex generators compared to other turbines in the area. The tests are performed on sites in the US and in Europe, namely in Great Britain, Spain, Sweden and Denmark.
“We believe that we are facing an international breakthrough. Return on investment is very high on this product, which means that the cost of purchasing and installing our product is often earned back in a matter of 12 to 15 months. After this period, there is money to be made,” adds Henriksen.
PowerCurve offers turnkey solutions, where the company handles product and mounting, a DIY kit with instructions and accessories as well as a basic package containing just the plastic components. With all packages, the components must be designed for the size and type of turbine in question.