Formaldehyde and the EU Green Deal
Formaldehyde and Energy
Formaldehyde is a building block for many applications. The properties it has are often incomparable to other substances, making it an enabler for quality properties that are sought by many diverse industries. For instance, in wind turbines.
Formaldehyde is used for the production of some epoxy resins which are then largely employed in composites and adhesives needed to produce wind turbine rotor blades and other structural elements. The skin of the blades, so to speak. Why? Their light weight, resistance to fatigue, good adhesion, and lack of shrinkage after cooling.
Epoxy resins are also used to coat and protect other parts including turbine insulators, stator end windings or field coils for rotor brackets. They can cover concrete and steel towers for windmills to increase their lifetime.
Whilst currently most parts of the exterior are produced with epoxy resins, polyurethane is also making its entrance into the scene. For now, polyurethane is mainly applied to the inner supporting structure of a wind turbine as a foam. These foams combine properties that are otherwise difficult to bring together: strength, lightweight and flexibility. Given the tremendous forces a wind turbine must resist, polyurethane is a perfect fit for the job. Where does formaldehyde come in? Formaldehyde is at the basis of methylene diphenyl diisocyanate (MDI), a chemical that is used primarily to manufacture the polyurethane foam.
Increasing circularity of the components
It is acknowledged wind turbine blades can be challenging to recycle due to the composite materials used in their production: separation of these materials is required before the recycling can effectively start. And that has not proven easy. But solutions are on their way.
For instance, there are projects exploring the possibility to convert polyurethane foams back into raw materials and ready to be used to create the exact same product all over again, without the foam losing out on quality. And in the UK, sections of retired turbine blades are being used in the reinforced concrete for the new high speed rail link HS2. By using the decommissioned blades, a 90 % carbon saving will be made in the production of the concrete reinforcement.