Decommissioned windblades used for storage system


SwitzerlandA partnership agreement between Enel Green Power and the Swiss energy storage company Energy Vault aims to integrate the recycling of decommissioned wind turbine blades into the weights used by their innovative gravitational energy storage system.

Wind power and energy storage have been brought together with the recent partnership agreement signed between Enel Green Power (EGP) and Energy Vault. Energy Vault is a Swiss technology company that specializes in gravitational energy storage systems. This partnership aims to integrate the gravity energy storage technology with the recycling of materials no longer needed at wind plants.

Gravitational storage

In 2019 EGP became aware of Energy Vault. Whose solution for storing energy employs purely mechanical technology and is inspired by hydroelectric plants. Which take advantage of gravitational forces and the movement of water masses to store and release energy on demand. Instead of water, however, Energy Vault uses blocks of solid material, as a storage medium. These large blocks, weighing around 35 tons each, are lifted to store electricity when an excess of energy is produced. And then when electricity is required, the blocks are lowered, exploiting the force of gravity to generate electricity as they descend. The entire operations are orchestrated by proprietary software and computer vision that control the velocity and movement of the blocks.

The benefits of this solution are the same as those of a pumped storage hydro plant. But at a much lower cost, with greater possibility of being replicated in any geographical context and greater efficiency. The Energy Vault technology can even exceed an efficiency level of 80%. Moreover, there are clear benefits compared to batteries. A plant of this type is not exposed to storage medium degradation, risk of fire, and has a long lifespan of 30-35 years. Moreover its eventual dismantling will not pose particular difficulties, as the blocks are composed of inert materials and are created directly on site.

Demonstration unit

Energy Vault has already interconnected a 5 MW Commercial Demonstration Unit (CDU) of the gravity storage technology in Ticino, and recently announced the new EVx product platform. This has a 30 story building architecture, is 40% shorter and fully flexible in terms of charging and discharging duration. Ideal for the utilization of wind blade fibers. The agreement signed with Enel Green Power has a series of successive steps planned.

A sustainable and circular solution

The question of dismantling wind plants is becoming more pertinent than ever. The average useful life of wind turbines is around 20 years and the first generators were installed at the beginning of the 2000s. For this reason, Enel Green Power has already been working for some time to identify strategies for the effective reuse of all the components of these power plants. The problem, however, mainly concerns the turbine blades. Which are made of composite material reinforced with fiberglass and/or carbon fiber, which is currently difficult to retrieve for recycling or reuse.

One possible solution is the “shredding” of the obsolete blades and their redeployment in the form of secondary raw materials. This could be used for making products for other sectors, such as the construction industry or furniture manufacturing. Based on this experience, another innovative idea came about: the integration of composite material from the former turbine blades into the blocks used by Energy Vault for gravitational storage.

‘The use of this material gives the blocks greater stability and robustness, increasing their durability and further lowering costs’, explains Irene Fastelli, Head of the Innovation Factory for the O&M and HSEQ functions at EGP.