Steel hybrid onshore wind towers installed with minimal effort: Development of lifting process

Abstract

The total costs per produced kilowatt-hour for wind turbines depend significantly on the investment costs. Thereby, the tower is a relevant cost component, which depends on the chosen supporting structure, the material, and especially on the erection process. Here, an innovative erection process is presented in order to minimize the wind turbine installation, which leads to excluding the extra tall cranes for installing the wind turbines with hub heights over 180 m. In order to propose the innovative erection process, a new hybrid lattice/tubular supporting structure for the onshore wind turbines is designed. The connection component between the tubular part and lattice structure is proposed considering the support functionality for the new erection process. Furthermore, the building steps of the complete erection process are explained. The operational and the lifting loads on wind turbine supporting structure are estimated, and consequently, the erection process stages were analyzed. Finally, the finite element simulation are performed to specify the critical stresses in subcomponents of the supporting structure in each lifting stage and to show the feasibility of the erection process. Moreover, the most critical points and the stages are investigated and stress level in the supporting structure components is computed.

Life Cycle Assessment of Tall Onshore Hybrid Steel Wind Turbine Towers

“…The case studies considered for this study form part of SHOWTIME research programme [17][18][19][20][21]. As part of this programme, different hybrid towers were studied.…”

“…As part of this programme, different hybrid towers were studied. In order to ensure structural and economical efficiency, but also feasibility of the manufacturing and erection process, two optimised hybrid towers have been suggested [17][18][19][20][21]. The latter are shown in Figure 2 and will be the focus of research in this study.…”

“…As part of the preliminary design, the total number of bolted connections required for each tower have been approximated, leading to a larger number of bolts for the 4-legged structure, owing to the more complex bracing configuration. Note that the tower connections have not been presented in detail herein, whilst additional information on their design, detailing and geometry can be found at [17][18][19][20][21].…”

“…Focusing on the critical transition piece, which aims to transfer the dynamic and wind loads from the tubular to the lattice part and subsequently to the foundation, a rigorous numerical study considering fatigue loading conditions was carried out [20]. Given that these types of towers allow for hub heights over 180 m, an innovative erection procedure, minimising time and effort was also suggested [21]. As these tall hybrid towers are a new structural system, with different erection process from the widely used tubular towers, comprehension of their environmental performance is missing and deemed essential.…”

Integrierter Hebeprozess für hybride Gittermastrohrtürme der Windenergie

“…Im Hinblick auf einen Vorentwurf eines vollskalierten Übergangsstücks wurden FE‐Simulationen in den vier Stadien durchgeführt, um herauszufinden, welches Stadium für welche Komponente des Übergangsstücks kritisch ist. Dabei wurden unterschiedliche Windbelastungsszenarien berücksichtigt . Die untersuchten Komponenten in den entsprechenden Stadien sind: S1: Endlage: Schale des Übergangsstücks Schale des Stahlrohrs oberer und unterer Flansch zur Verbindung von Übergangsstück und Rohrturm S2: Zustand kurz bevor das Rohrteil das Übergangsstück erreicht: Bodenplatte an der Unterseite des Stahlrohrs zur Herstellung der Verbindung S3: Gondel und Rotor werden auf das Rohrteil gesetzt: für keine Komponente kritisch S4: Gondel und Rotor in Endposition und kurz vor der endgültigen Verbindung: oberer Stahlring des Stahlrohrturms zur Herstellung der Verbindung …”