What is a flywheel energy storage system?

A flywheel energy storage system is a device that stores energy in a rotating mass. It typically includes a flywheel/rotor, an electric machine, bearings, and power electronics. Fig. 3. The Beacon Power Flywheel, which includes a composite rotor and an electric machine, is designed for frequency regulation.

How much energy can a flywheel store?

The small energy storage composite flywheel of American company Powerthu can operate at 53000 rpm and store 0.53 kWh of energy . The superconducting flywheel energy storage system developed by the Japan Railway Technology Research Institute has a rotational speed of 6000 rpm and a single unit energy storage capacity of 100 kW·h.

How much energy is stored in a composite flywheel?

Typical energies stored in a single unit range from less than a kilowatt-hour to levels approaching 150 kilowatt-hours. Thus, a single composite flywheel can be equivalent, in stored energy, from one to more than 100 automotive batteries. Moreover, in flywheel systems, the stored energy and output power are relatively independent of each other.

How many 20 MW flywheel energy storage systems are there?

Two 20 MW flywheel energy storage independent frequency modulation power stations have been established in New York State and Pennsylvania, with deep charging and discharging of 3000–5000 times within a year . The Beacon Power 20 MW systems are in commercial operation and the largest FESS systems in the world by far.

What is the core element of a flywheel?

The core element of a flywheel consists of a rotating mass, typically axisymmetric, which stores rotary kinetic energy E according to (Equation 1) E = 1 2 I ω 2 [J], where E is the stored kinetic energy, I is the flywheel moment of inertia [kgm2], and ω is the angular speed [rad/s].

What are some new applications for flywheels?

Other opportunities for flywheels are new applications in energy harvest, hybrid energy systems, and flywheel’s secondary functionality apart from energy storage. The use of new materials and compact designs will increase the specific energy and energy density to make flywheels more competitive to batteries.