What is a flywheel energy storage system?

First-generation flywheel energy-storage systems use a large steel flywheel rotating on mechanical bearings. Newer systems use carbon-fiber composite rotors that have a higher tensile strength than steel and can store much more energy for the same mass. To reduce friction, magnetic bearings are sometimes used instead of mechanical bearings.

Could flywheels be the future of energy storage?

Flywheels, one of the earliest forms of energy storage, could play a significant role in the transformation of the electrical power system into one that is fully sustainable yet low cost.

How much energy does a flywheel store?

Indeed, the development of high strength, low-density carbon fiber composites (CFCs) in the 1970s generated renewed interest in flywheel energy storage. Based on design strengths typically used in commercial flywheels, σmax /ρ is around 600 kNm/kg for CFC, whereas for wrought flywheel steels, it is around 75 kNm/kg.

Are flywheel energy storage systems a good alternative to electrochemical batteries?

Flywheel energy storage systems are considered to be an attractive alternative to electrochemical batteries due to higher stored energy density, higher life term, deterministic state of charge and ecological operation. The mechanical performance of a flywheel can be attributed to three factors: material strength, geometry, and rotational speed.

How do you calculate the energy capacity of a flywheel?

The following equations describe the energy capacity of a flywheel: (2) E m = α ′ α ′ ′ α ′ ′ ′ K σ / ρ (3) E v = α ′ α ′ ′ α ′ ′ ′ K σ where α ′ is the safety factor, α ′ ′ the depth of discharge factor, α ′ ′ ′ the ratio of rotating mass to the total system mass, σ the material’s tensile strength, K the shape factor, and ρ the density.

Are flywheel-based hybrid energy storage systems based on compressed air energy storage?

While many papers compare different ESS technologies, only a few research , studies design and control flywheel-based hybrid energy storage systems. Recently, Zhang et al. present a hybrid energy storage system based on compressed air energy storage and FESS.