
Flywheel energy storage (FES) works by accelerating a rotor () to a very high speed and maintaining the energy in the system as . When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of ; adding energy to the system correspondingly results in an increase in the speed of th. The system consists of a 40-foot container with 28 flywheel storage units, electronics enclosure, 750 V DC-circuitry, cooling, and a vacuum system. [pdf]
A flywheel operates on the principle of storing energy through its rotating mass. 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.
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.
Flywheel Energy Storage System (FESS) can be applied from very small micro-satellites to huge power networks. A comprehensive review of FESS for hybrid vehicle, railway, wind power system, hybrid power generation system, power network, marine, space and other applications are presented in this paper.
The major components that make up a flywheel configured for electrical storage are systems comprising of a mechanical part, the flywheel rotor, bearings assembly and casing, and the electric drive part, inclusive of motor-generator and power electronics.
Other opportunities are new applications in energy harvest, hybrid energy systems, and flywheel’s secondary functionality apart from energy storage. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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.

The top companies in the energy storage system integrator market, based on shipments, include CATL, BYD, EVE Energy, REPT BATTERO, and Hithium1. In the AC side, the top integrators are Tesla, Sungrow, CRRC ZHUZHOU INSTITUTE, Fluence, and Envision2. In the DC side, the top integrators are CATL, BYD, HyperStrong, RelyEZ Energy, and Narada Power2. Sungrow dominated the market with 16% of global market share, followed by Fluence and Tesla34. [pdf]
While XYZ Storage and Envision tied at third place, stated the report. For Europe, energy storage system integrator market concentration was on the rise in 2023, compared with the relatively fragmented situation in 2022. The top three players, Nidec, Tesla and BYD, accounted for 68% of the European market share in 2023, increasing by 26% YoY.
Because of the strong correlation between the system integrator market and the wider energy storage industry, this research touches on broader energy storage topics, such as policy effects, market growth and supply chain.
Additionally, Samsung SDI and LG’s energy-storage cell shipments totaled nearly 14 GWh in 2023, translating to a slightly lower market share of 7%. For utility-scale energy storage, CATL, BYD, EVE Energy, Hithium, and REPT BATTERO shipped the most in 2023. CATL shipped more than 65 GWh and the rest less than 22 GWh.
InfoLink sees global energy-storage installation increase by 50% to 165 GWh and energy-storage cell shipments by 35% to 266 GWh in 2024. Database contains the global lithium-ion battery market supply and demand analysis, focusing on the cell segment in the ESS sector.
The world shipped 196.7 GWh of energy-storage cells in 2023, with utility-scale and C&I energy storage projects accounting for 168.5 GWh and 28.1 GWh, respectively, according to the Global Lithium-Ion Battery Supply Chain Database of InfoLink.
The top five largest energy storage cell manufacturers in the first half are CATL, EVE Energy, REPT, Hithium, and BYD. CATL secured the top position with orders from major customers like Tesla and Fluence. EVE Energy received orders from all big customers, sustaining second place in the industry.

Flywheel energy storage (FES) works by accelerating a rotor () to a very high speed and maintaining the energy in the system as . When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of ; adding energy to the system correspondingly results in an increase in the speed of th. In FESSs, electric energy is transformed into kinetic energy and stored by rotating a flywheel at high speeds. An FESS operates in three distinct modes: charging, discharging, and holding. [pdf]
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.
The operational mechanism of a flywheel has two states: energy storage and energy release. Energy is stored in a flywheel when torque is applied to it. The torque increases the rotational speed of the flywheel; as a result, energy is stored. Conversely, the energy is released in the form of torque to the connected mechanical device .
Flywheel energy storage systems have a long working life if periodically maintained (>25 years). The cycle numbers of flywheel energy storage systems are very high (>100,000). In addition, this storage technology is not affected by weather and climatic conditions . One of the most important issues of flywheel energy storage systems is safety.
There are losses due to air friction and bearing in flywheel energy storage systems. These cause energy losses with self-discharge in the flywheel energy storage system. The high speeds have been achieved in the rotating body with the developments in the field of composite materials.
The operation of the electricity network has grown more complex due to the increased adoption of renewable energy resources, such as wind and solar power. Using energy storage technology can improve the stability and quality of the power grid. One such technology is flywheel energy storage systems (FESSs).
Small applications connected in parallel can be used instead of large flywheel energy storage systems. There are losses due to air friction and bearing in flywheel energy storage systems. These cause energy losses with self-discharge in the flywheel energy storage system.
We are deeply committed to excellence in all our endeavors.
Since we maintain control over our products, our customers can be assured of nothing but the best quality at all times.