As the first multi-megawatt wind turbines reach their end of life and need to be dismantled, recycling solutions are becoming increasingly important. The rotor blades of a wind turbine are a critical and costly component of a wind turbine system. They can be up to 100 m long and are mainly made of fibreglass composites, and the most common dismantling method currently used is incineration, which leaves 60% of the scrap as (environmentally harmful) ash. Attempts at recycling include grinding and reuse (REACT consortium), which has proved difficult due to concerns about the quality of the recyclate, and chemical recovery by solvolysis (ReFiber ApS, Denmark), which retains most of the tensile strength of the glass fibre but uses harsh and hazardous chemicals and is very expensive. Some research has looked at alternative materials for rotor blades that are easier to recycle, such as thermoplastic matrix composites (NAReC, UK), bamboo and bio-based adhesive (DTU, Denmark), PET foam (Alcan Airex) and flax (University of Cambridge). However, so far no suitable solution has been found in terms of stiffness, strength, manufacturability and cost.
The objectives of this project are: (1) to develop know-how in order to develop, together with industrial partners and with public funding, a more environmentally friendly rotor blade for megawatt-sized wind turbines and (2) to build and test a small demonstration rotor on a running wind turbine at a site in the canton of St. Gallen.
We are currently in the process of producing and testing fibre composite materials from linseed oil and flax!
This collaboration between the HSR institutes IET and IWK is internally funded.