How can flywheels be more competitive to batteries?

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

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.

What is a flywheel energy storage system?

A typical flywheel energy storage system , which 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.

What is the relationship between flywheels and Li-ion batteries?

Energy buffer and hybrid storage system An excellent analogy for the relationship between flywheels and Li-ion batteries is the computer’s memory architecture. A computer has multiple layers of memory devices. Fast memories such as cache and RAM (random access memory) are similar to FESS: fast-responsive and higher power/speed ratings.

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.