Higher towers significantly increase the energy yield of a wind turbine generator on sites with a high wind shear. At the same time, they pose considerable challenges in terms of transportability and costs. Siemens offers an in- novative and economically viable tower concept to allow its wind turbines reach heights above 100 m. The Bolted Steel Shell Tower consists of multiple tower sec- tions, mounted on top of each other (Figure 1). Each section is made out of steel shells which are assembled together on site. The steel shells are produced from bended steel plates and can be transported to site with standard trucks. They are bolt- ed together with HRC (tension-controlled) bolts to form a tow- Depending on the hub height, the towers are constructed of 9 or more sections with a bottom diameter of 8 m or more. The modular space concept of the Bolted Steel Shell Tower al- lows for very high hub heights (in excess of 140 m) with very low transportation requirements. The tower is erected in a short time and requires minimal maintenance. In fact, the HRC bolts require no re-torquing during the tower's lifetime. Answers that last.

The tower includes a lift and ladder to reach the nacelle. A transformer unit can be installed within the tower. The door has standard dimensions to allow for the exchange of internal components. The tower can be fitted with aviation warning lights which can be bolted to the outside tower wall at any horizontal section connection. Figure 2. 3-D model and top-view of a tower section showing the steel shells The Bolted Steel Shell Tower features the following key benefits: • Virtually no restriction on the maximum hub height, as long as a suitable crane is available • Low steel requirement compared...