In idyllic Lower Lusatia, a region southeast of Berlin in Brandenburg, the world’s largest wind turbine is currently being built in the village of Schipkau. The tip of its upward-pointing blade will be 365 meters above the ground. The makes it almost as tall as Berlin’s landmark Television Tower.
“The height allows for a larger rotor blade diameter,” says Stephan Mayer, head of testing and certification of support structures for wind turbines at TÜV SÜD. The greater area covered by the blades leads to correspondingly higher potential energy yields. In addition, the wind is stronger and more constant at heights above 300 meters in comparison to standard wind turbines which usually are about 200 meters high. In Germany in particular, it is not easy to find a suitable site for the construction of such massive structures that have good wind conditions throughout the year because of regulations regarding the protection of the environment or the reduction of emissions. Therefore, it is imperative “to generate as much electricity as possible with each turbine,” as Mayer points out. Replacing existing and often outdated wind turbines with new, extra-tall models could potentially increase the output tenfold.
“Companies are given the opportunity to integrate prototypes into their systems in order to prove their suitability for practical use.”
Tubular steel is often used for wind turbines, which are manufactured in 30-meter-tall segments and then built together onsite. At greater heights, this material is no longer stable enough. Furthermore, the taller individual segments are sometimes difficult if not impossible to transport along roads and across or under bridges.
Alternative concepts demonstrate a lot of potential for these new heights. Hybrid towers are made of steel and concrete. The importance of sustainable materials is also becoming more important in the wind energy sector. Prototypes made of wood are already being tested. The challenge of working with wood is the construction, as Mayer explains. “The connections between individual parts are a weak spot.” This could make more maintenance work necessary in the future.
New materials and construction methods also pose challenges for the testing and certification that Stephan Mayer and his team carry out. In some cases, there is only a very small database as the foundation for the assessment. Mayer says, “A wood tower, for instance, also has joints that are glued together. How these can be designed to withstand the dynamic loads that wind turbines generate isn’t regulated by any current standards.” Extensive series of tests would therefore be essential here.
Testing alternative materials is a new challenge for wind turbine manufacturers. However, this field has great potential, as the “Wind-an-Land” law of 2023, aims to significantly increase the expansion of wind power in Germany. In Brandenburg, where the largest wind turbine in the world is being built, 1,000 new turbines would have to be built by 2030 to achieve the “Wind-an-Land” laws target. Promoting projects that foster sustainable innovation would be an important contribution to strengthening wind power for the future.
