Energy Vault, a Swiss next-generation long-duration energy storage startup, has partnered with Enel Green Power, an Italian renewable energy company, to integrate the recycling of decommissioned wind turbine blades into the weights used by Energy Vault’s gravity-based energy storage system.

The average useful life of wind turbines is around 20 years and most first-generation wind turbines are now due to be replaced. However, turbine blades made of a composite material reinforced with fiberglass or carbon fiber and are difficult to recycle or reuse.

The partners state that the integration of composite material into the weights used for gravitational storage will provide them greater stability and robustness while increasing durability and lowering costs.

Founded in 2017, Energy Vault’s technology utilizes the same fundamentals of gravity and kinetic energy as a pumped hydro system but replaces the water with custom-made composite blocks. These blocks are lifted to a higher elevation using electricity generated from solar and wind during times of abundant supply. Later, when the supply of renewable energy is low, these elevated blocks are returned to the ground and the kinetic energy generated from the falling brick is turned back into electricity. Energy Vault has yet to commercialize its technology. The company operates a commercial demonstration unit in Switzerland connected to the Swiss national utility grid since July 2020.