Netherlands-based energy storage firm S4 Energy has installed a 9MW hybrid-energy storage project near Amsterdam that uses flywheels and a battery.
The KINEXT energy-storage flywheel and battery project has been in full operation since April and can release and store energy to deliver grid frequency regulation services to ensure network stability.
In addition to stabilising the grid, the storage system also offers active support to the local Luna wind energy park where it will act as a short-term damper to prevent imbalance in the output of the turbines and prevent curtailment of production.
S4 Energy’s aim for this pilot project is to demonstrate that the net revenues of wind energy can be significantly improved by incorporating an energy storage system, in turn making wind energy projects less dependent on subsidies.
Each KINEXT unit contains a flywheel with a high mass (5,000 kg) and large diameter (around 2.6 meters), which has a peak spin speed of around 1,800 rpm.
A motor and drive supplied by ABB takes excess energy from the grid and uses it to speed up the rotation of the flywheel, so it is stored as kinetic energy; it can then use this energy to deliver frequency regulation services to the grid when required.