Workers cut apart a retired German wind turbine blade and pulled out 1.3 metric tons of balsa wood from inside it. The blade was taken through a water jet, shredder and impact mill, turning material that once went to cement-kiln disposal into reusable wood products.
Peter Meinlschmidt and the blade cut
Peter Meinlschmidt, the project manager involved in the recycling process, said the balsa comes free as chips and pieces rather than dust. That matters because the material can move into two use streams: lightweight wood fiber insulation mats for buildings and a wood foam for packaging.
The process starts with a vehicle mounted water jet lance that cuts a retired blade into sections roughly 33 to 66 feet long. A mobile shredder then reduces those sections to fragments about the size of a palm before they enter an impact mill, where the balsa separates from the fiberglass and resin at high speed.
Fraunhofer Institute for Wood Research process
A 130 foot rotor blade weighs about 26 metric tons and is made up of roughly 24 metric tons of glass fiber reinforced plastic, 1.3 metric tons of balsa wood and 0.5 metric tons of metal. The recovered wood is then processed into insulation mats, while a separate stream is ground finer and treated with a foaming additive to make packaging foam.
Until this process existed, old rotor blades were burned as composite material, usually in cement factories. The new method gives the balsa a second use instead of sending it straight into combustion.
Germany’s turbine end of life
Germany has roughly thirty thousand turbines in operation, so more blade material is reaching end of life. The recovered balsa inside a blade still has useful properties after roughly twenty years at the tip of the rotor, which is why the extraction process can turn a discarded section into building and packaging feedstock.
How much of a full retired blade can be recovered economically at scale is the open question. For now, the practical result is straightforward: one retired blade yielded 1.3 metric tons of wood that can be used again instead of discarded.
