Energy Storage Flywheels

Energy Storage FlywheelsEnergy storage flywheels feature a mass rotating around an axis. The main purpose of flywheels is to store energy in the form of kinetic energy, which can then be used to generate power. By accelerating a rotor at high speeds, energy storage flywheels maintain the system’s energy as rotational energy. Due to their many benefits, flywheel energy storage technologies are expected to grow significantly in demand as a replacement for conventional batteries for applications requiring high power density and short regeneration cycles. 

Because flywheel energy storage relies on high-speed rotors to capture and maintain energy, it’s important that these rotors be adequately tested to ensure optimal performance. At Test Devices by SCHENCK, we offer industry-leading spin testing services for customers working with high-speed rotating components, including those found in flywheel energy storage systems. 

How Do Energy Storage Flywheels Work?

Energy storage flywheels store energy in the form of kinetic energy through the use of a high-speed rotor with very low frictional losses. Using an integrated motor-generator, a small amount of electricity is used to keep the flywheel rotor spinning at speed until the stored energy is required. When the stored energy is required, as the flywheel decelerates slowly the motor-generator converts the spinning motion back into electricity. The mass and speed of the flywheel determines the amount and duration of energy available.  

Different flywheel designs can reach different speeds—or storage capacities— as well as have different levels of friction, inertia, and other factors that ultimately determine their energy storage efficiency. You can gauge the energy storage capacity of a flywheel as a proportion of its moment of inertia multiplied by the square of the object’s angular velocity.

Applications of Energy Storage Flywheels

The higher energy efficiency and long service life of energy storage flywheels make them an ideal choice for various applications, including the following:

Grid Energy

Alternative green energy sources such as windmill farms and power gas turbine “peaking units” experience variations in power generation that can be stabilized through the use of energy storage flywheels. In addition, the renewable energy generated by these sources will require grid storage. While there are many other contenders for energy storage, they each come with their own unique drawbacks. For example, chemical batteries experience degradation over time and lithium-ion batteries are difficult to source. 

Flywheels last much longer than other battery alternatives. They can charge and discharge energy all day everyday for several decades and will still have 100% capacity. 


The military industry requires high-density energy storage for powering high-energy weaponry and other mission-critical systems. Current research efforts are examining military shipboard flywheel integration and the safety correlated with large-scale energy storage.

Flywheel motor-generator technology gives environmentally conscious military bases access to a “greener” solution that is more energy-efficient than other battery opterions while also resolving space and maintenance constraints. As a result, military installations with flywheels see an immediate decrease in operational costs.


Flywheel systems can also be used as energy storage units for residential applications, substituting for large in-home battery systems. Recent advances in flywheel technology include units that can be cycled for over 20 years, providing a way to store clean energy from renewable sources such as hydro, wind, and solar.  

Advantages of Energy Storage Flywheels

Energy storage flywheels offer a wide range of benefits over other energy storage systems. These advantages include:

  • Increased efficiency. Energy storage flywheels offer increased energy efficiency, making them a more environmentally friendly option. 
  • More reliability. The reliability of flywheel energy storage ensures a predictable, consistent power supply when needed.
  • Reduced costs. Because of their energy efficiency and minimized maintenance needs, energy storage flywheels lead to reduced operational costs.
  • Speed of charge. Compared to other battery types such as lithium-ion batteries and chemical batteries, energy storage flywheels feature the ability to recharge very quickly.

Test Devices by SCHENCK: Your Partner for Spin Testing Energy Storage Flywheels

The energy storage market is continuing to grow, bringing with it an increased demand for reliable flywheels. While lithium-ion and other battery types are the most commonly used energy storage systems in North America, the advantages of flywheel energy storage are projected to increase in demand over the next several years. 

Because flywheel rotors rotate at very high speeds, it’s crucial that they undergo rigorous spin testing processes to ensure performance, manufacturability, and compliance with industrial standards. At Test Devices by SCHENCK, we offer spin testing services such as overspeed testing, LCF testing, and more to validate flywheel designs and support manufacturing processes. For more information about how our spin testing capabilities can aid in the development of reliable energy storage flywheels, contact us or request a quote today.