Re-use of delaminated composite material from decommissioned wind turbine blades

Abstract

More and more wind turbines are erecting in the landscape, stemming from the need for sustainable energy. However, less attention is paid to the secondary effects of these wind turbines, more specifically, the wind turbine blades. Wind turbine blades are made of composite material, a material that provides many advantageous properties for the desired functionality. Nevertheless, the material is difficult to reuse or recycle after the lifespan of the wind turbine blade. This challenge is expected to result in thousands of tons of decommissioned blades entering the market in the coming years which, due to the absence of good alternatives, are most likely to be disposed of in an unsustainable manner.

This project focuses on how composite material from decommissioned wind turbine blades can be reused in order to retain the value embedded in the material. It explores how delamination can potentially add to design freedom of the material for it to be used in a scalable way and match the large influx of the material. Focus is put on the curved elements of the blade: the inboard and outboard sections. Aside from producing scientific knowledge on the topic, the aim is to exhibit the findings through means of a demonstrator of a potential reuse application.

In chapter one, the thesis starts with research into background information, identifying the knowledge gap, setting the scope and conceiving the mission and research questions for the project. Then, in chapter two, a better understanding of a wind turbine blade is formed based on a reference blade. After this the geometry of the blade parts in focus, together with the material composition is researched. Chapter three dives into the possibilities of retrieving elements out of wind turbine blades and looks at the characteristics of these elements.

In chapter four the delamination of the sandwich structured wind turbine material is explored. It is investigated how this can be done and what potentially influences this process. Then, in chapter five the material characteristics of the retrieved and delaminated elements are analysed. This showed that the material can be elastically deformed, opening up the floor for a broader range of reuse applications.

The most suitable reuse application is then methodically determined in chapter 6. Based on, amongst other things, the material qualities and the vision, the choice fell on a bus shelter. A concept of this is then proposed and concretised in the form of a demonstrator. It exhibits the possibilities of the material and embodies the approach for facilitating reuse of decommissioned wind turbine blades on large scale as presented in the project.

In the end, the report concludes with an evaluation of the design and the process in the form of a discussion, a summary of the findings and multiple recommendations to improve future sustainability with respect to wind turbine blade material