Wind turbines with hub heights of over 140 metres are no longer a rarity today. In view of the technological progress, a further increase in height can be expected. Large hub heights are required, in particular, for operating onshore low-wind sites in order to enable the cost-effective operation of the wind turbine. But even so, conventional joining and assembly technologies reach their limits at these heights. If the costs for production, transport and construction rise to over 30% of the total costs, wind turbines are no longer economically viable.
In order to counteract this development, a consortium from science and industry is developing new production techniques for tubular steel towers for tall wind turbines with a hub height of over 120 metres. As a result a new, holistic tower concept should reduce not only costs but also enable a cost-efficient increase in hub heights for onshore wind turbines.
In extensive experiments, the project partners Fraunhofer Institute for Wind Energy Systems (IWES), Fraunhofer Research Institution for Large Structures in Production Engineering (IGP) and Nordex SE are developing innovative bracing concepts and optimising the buckling behaviour of tower segments under realistic conditions. The ideal material for resource-efficient towers is to be found, among other things, by using fatigue tests. In a subproject, Nordex is also developing a turbine control system.
The project “Holistic, resource-efficient tower concept for wind turbines with large hub heights for onshore, low-wind sites (GreT)” will run until the end of December 2019.