Jordan A. Davis

In the advanced energy storage market, lithium-ion batteries remain the primary battery technology for energy storage systems. They are used in a variety of storage applications from energy storage sited at commercial and industrial facilities to residential energy storage to multi-megawatt utility-scale energy storage installations.

Despite lithium-ion batteries’ market dominance, they aren’t the only available option. Dynapower has deployed our energy storage inverters alongside other battery technologies including flywheel systems and flow batteries. Here we take a deeper dive into how these batteries work.

Flywheel Systems

flywheel system

What Is a Flywheel System?

Flywheel energy storage systems (FESSs) store electric energy input as kinetic energy through the system’s rotor. The rotor spins in a nearly frictionless enclosure, which allows it to maintain its inertia and continue to turn, even after power is lost. Once the system loses connection to the external power source, the rotor’s kinetic energy is converted back to electrical energy. This characteristic enables FESSs to provide backup power to connected utility systems during power fluctuations or incidents of total power loss.

How Does It Work?

Most flywheel energy storage systems feature a large rotating cylinder. This component consists of a rim attached to a shaft and is supported by magnetic bearings on the stator. To maximize energy efficiency, the system operates within a vacuum to minimize drag.

When a connected utility system requires additional power, the flywheel—which is connected to a motor-generator—starts to convert the kinetic energy to electricity.


FESSs offer many benefits, such as:

  • Little to no environmental impact
  • Longevity (over 100,000 full-depth discharges if properly used and over 175,000 full-depth discharges in newer systems)
  • Minimal maintenance requirements
  • Versatility (suitable for use in short-term ride-through power and long-term storage applications)


FESSs are used in a wide variety of applications, including:

  • FESSs are used in a wide variety of applications, including:
  • Fast area regulation
  • Frequency response
  • Providing high-quality and reliable general electrical service power
  • Providing ride-through power as other systems are enabled
  • Subsystems in hybrid vehicles that frequently stop and start

Flow Batteries

flow battery

What Are Flow Batteries?

Flow batteries—also referred to as redox flow batteries—employ electrochemical energy storage principles. Their function is similar to that of rechargeable batteries and fuel cells.

How Do They Work?

These batteries contain two dissolved chemical solutions that are separated by a membrane. This battery design allows for both the conversion of stored liquid energy into electricity and replenishment of the depleted energy stores.


Flow batteries offer a number of unique benefits, including their nearly instant rechargeability. Operators can simultaneously recover the spent solution for re-energization and replace it with a new electrolyte solution for future operation.

Other advantages of flow batteries include:

  • Recyclability (both of the electrolyte solution and battery container)
  • Flexibility (in regards to control over power ratings and energy ratings)
  • Durability and longevity
  • Safety (minimal risk of fire)
  • Affordability (low manufacturing cost and practical economies of scale for use in small and large capacities)
  • Ease of use


Flow batteries can be used in almost all environments and industries. Common applications include:

  • Sustainable energy generation. Flow batteries can be used during wind fluctuation, storage during peak solar collection times, and smart grid balance.
  • Transportation. Predecessors to flow batteries that used zinc-bromine and vanadium were used in golf carts and automobiles.
  • Industrial and commercial energy storage. Redox flow batteries can be used as short-term storage solutions. They can store energy for two to ten hours with power ratings ranging from 10’s of kW to 10’s of MW.

Dynapower’s Energy Storage Systems

Investing in a flexible and reliable energy storage solution can reduce energy costs for end users and help build a more sustainable grid.

At Dynapower, we specialize in delivering complete energy storage systems. Our expert team works with you to determine the optimal setup for your industry and application. We provide both custom and standard solutions tailored to your company’s unique energy input and storage needs. To get started on your next energy storage system project, contact us or request a quote today.