Selection of Sustainable Wind Turbine Tower Geometry and Material Using Multi-Level Decision Making

Abstract

Wind turbine tower design looks primarily at the structural integrity and durability of the tower. Optimization techniques are sometimes employed to maximize the loading capability while reducing material use and cost. Still, the tower is a dynamic part of a complex wind energy conversion system. During system operation, the tower is excited and sways back and forth. This undesirable movement increases cyclical loading on the tower and drivetrain components. To minimize this motion the tower frequency must be offset from the natural frequency of other components. Hence, it is necessary to look at the relationships that exist between the tower and other wind turbine components, such as the rotor, nacelle, and foundation. In addition, tradeoffs between cost, structural performance, and environmental impact can be examined to guide the designer toward a truly sustainable alternative to fossil fuels. Ultimately, an optimal design technique can be implemented and used to automate tower design. This work will introduce the analytical model and decision-making architecture that can be used to incorporate greater considerations in future studies. In this paper, nine wind turbine tower designs with different materials and geometries are analyzed using Finite Element Analysis (FEA). The optimal tower design is selected using a multi-level variation of the Hypothetical Equivalents and Inequivalents Method (HEIM). Using this analysis, a steel tower with variable thickness has been chosen. The findings reaffirm that steel is a favorable choice for turbine tower construction as it performs well on environmental, performance, and cost objectives. The method proposed in this work can be expanded to examine additional design goals and present a higher fidelity model of the wind turbine tower system in future work.