Repurposing wind turbine blades as a construction material

Abstract

Wind turbines are decommissioned when they reach their endoflife. The reason for reaching endoflife varies per wind turbine, but they all have in common that the wind turbine blades can not be recycled and thus end up as waste. Since a growing amount of wind turbines will reach their endoflife the coming decade, the waste problem will increase. To solve or limit this problem, the lifetime of a blade can be extended, or a sustainable endoflife treatment can be established. This is currently not available yet. This research focuses on repurposing wind turbine blades. The objective is not to find one application, but rather to propose a method that enables large scale processing of wind turbine blades, for applications in the construction industry. Since to date it is uncommon to repurpose wind turbine blades, Two processes are proposed to give guidance on how to repurpose wind turbine blades. The first process is meant to repurpose as many blades as possible, by sawing the blade in plates and beams that can be applied to construction projects. The second process gives guidance to a project team that wants to incorporate wind turbine blades in their construction project, which can raise awareness for the waste problem. Both processess are supported by a grasshopper script. This script enables the user to either find an efficient mapping of elements that can be extracted from the blade, or gives design freedom depending on the aim of the repurpose project. The first process is further worked out. A geometry model of an actual wind turbine blade is analyzed and categorized in panels with a homogeneous material layup. On this panels, a nesting pattern of plates and beams, as commonly used in the construction industry, is projected which can later be sawn into relative flat plates and beams. With this, almost half of the blade panels can be turned into useful construction elements. The cross section of a blade consists of various functions, and thus various material structures. Three categories are distinguished: Spar caps, shell panels and the shear web. For each of these categories, the material layup and properties are analysed, which has led to an advice on possible applications. Spar caps are strong, stiff and have a homogeneous cross section. They can be repurposed as structural beams. Shell panels are light and stiff and can be repurposed as partition walls, formwork or flooring. The shear web is light, stiff, and entails good insulation properties. This can be repurposed as building cladding. Although this research does not contain sample tests, the material properties of the blade are provided and are of significant value, despite their 27 years of service.