Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy.
When charging, electrical energy from the grid or a power source is used to accelerate the flywheel to very high speeds. This is done by the motor/generator acting as a motor, converting electrical energy into kinetic energy and storing it in the spinning flywheel.
Think of it as a mechanical storage tool that converts electrical energy into mechanical energy for storage. This energy is stored in the form of rotational kinetic energy. Typically, the energy input to a Flywheel Energy Storage System (FESS) comes from an electrical source like the grid or any other electrical source.
The cost of a flywheel energy storage system is $6,000. Each kilowatt is priced at $1,333 a kilowatt. This flywheel energy storage design is a viable electricity source in homes. It functions to meet peak power demands within 25 seconds, allowing for significant savings in energy costs.
Because a flywheel must be accelerated by an external force before it will store energy, it is considered a “dynamic” storage system. The rate at which the flywheel spins remains nearly constant because of the vacuum-like container, which prevents friction from slowing the revolution.
To connect the Flywheel Energy Storage System (FESS) to an AC grid, another bi-directional converter is necessary. This converter can be single-stage (AC-DC) or double-stage (AC-DC-AC). The power electronic interface has a high power capability, high switching frequency, and high efficiency.