Flywheel Energy Storage

Detailed overview of innovation with sample startups and prominent university research

What it is

Flywheel energy storage (FES) systems store energy in the form of kinetic energy by spinning a rotor at high speeds. This technology offers several advantages, including rapid response times, high power output, long cycle life, and environmental friendliness. FES systems are suitable for applications requiring short-duration energy storage and high power bursts, such as frequency regulation, voltage support, and uninterruptible power supplies (UPS).

Impact on climate action

Flywheel Energy Storage in Thermal & Mechanical Storage boosts climate action by enhancing grid stability and renewable energy integration. By storing excess energy as rotational kinetic energy, this innovation provides efficient, rapid-response energy storage, reducing reliance on fossil fuels and accelerating the transition to a sustainable, low-carbon energy system.


  • Flywheel: The flywheel is a rotating mass that stores kinetic energy. It is typically made of high-strength materials, such as steel or carbon fiber composites, and is designed to minimize energy losses due to friction and wind resistance.
  • Motor/Generator: The motor/generator is used to accelerate the flywheel during charging and to convert the kinetic energy of the flywheel back into electricity during discharge.
  • Bearings and Vacuum Chamber: Flywheels are supported by low-friction bearings and often housed in a vacuum chamber to minimize energy losses due to air resistance.
  • Power Electronics: Power electronics are used to control the motor/generator and manage the flow of energy between the flywheel and the grid or load.

TRL : 7-8

Prominent Innovation themes

  • High-Speed Flywheel Designs: Innovations in materials and design are enabling the development of flywheels that can spin at higher speeds, increasing energy storage capacity and power output.
  • Magnetic Bearings: Magnetic bearings eliminate friction and wear, improving efficiency and extending the lifespan of FES systems.
  • Composite Flywheel Materials: Carbon fiber composites and other advanced materials are being used to create lighter and stronger flywheels, further increasing energy density and performance.
  • Hybrid FES Systems: Hybrid systems that combine flywheels with other energy storage technologies, such as batteries or supercapacitors, can offer a wider range of grid services and improve overall system performance.

Other Innovation Subthemes

  • Advanced Material Development for Flywheels
  • Enhanced Efficiency with Magnetic Bearings
  • Grid-Scale Integration Strategies
  • Hybrid Energy Solutions for Enhanced Performance
  • Miniaturization for Portable Applications
  • Safety and Reliability Optimization in Flywheel Systems
  • Smart Grid Integration for Optimized Performance
  • Thermal Management for Prolonged Lifespan
  • Grid Stability Solutions with Rapid Response Energy Storage
  • Modular Design Concepts for Scalability
  • Remote Area Power Supply (RAPS) Solutions
  • Energy Recovery in Transportation Systems
  • Renewable Energy Integration with Flywheels
  • Urban Energy Management Solutions
  • Data Center Backup Solutions with Flywheels
  • Residential Energy Storage Applications
  • Flywheel Energy Storage in Aerospace

Sample Global Startups and Companies

  1. Amber Kinetics:
    • Technology Enhancement: Amber Kinetics develops advanced flywheel energy storage systems for grid-scale applications. Their flywheel systems use kinetic energy to store and release electricity, offering fast response times and high cycling capabilities. The company’s proprietary flywheel technology features low-friction bearings, high-strength materials, and advanced control algorithms for efficient energy storage and retrieval.
    • Uniqueness of the Startup: Amber Kinetics stands out for its innovative approach to flywheel energy storage, focusing on reliability, scalability, and cost-effectiveness. Their flywheel systems are designed for long-duration energy storage, enabling applications such as renewable energy integration, grid stabilization, and peak shaving. The company’s commitment to advancing flywheel technology and addressing grid challenges makes them a leader in the energy storage market.
    • End-User Segments Addressing: Amber Kinetics serves utility companies, renewable energy developers, and grid operators seeking flexible and resilient energy storage solutions. Their flywheel systems are deployed in grid-connected installations, microgrids, and remote off-grid sites, providing reliable backup power, frequency regulation, and renewable energy smoothing.
  2. Beacon Power:
    • Technology Enhancement: Beacon Power specializes in grid-scale flywheel energy storage systems for frequency regulation and grid stability applications. Their flywheel systems utilize high-speed rotating mass to store and release energy rapidly, providing grid services such as frequency regulation, voltage support, and grid stabilization. Beacon Power’s flywheel technology features advanced control algorithms and grid integration capabilities for seamless integration into power systems.
    • Uniqueness of the Startup: Beacon Power stands out for its focus on frequency regulation and grid stability applications, leveraging flywheel technology to enhance grid reliability and efficiency. Their flywheel systems offer fast response times, high efficiency, and long service life, making them suitable for demanding grid support functions. The company’s expertise in grid integration and energy market participation positions them as a trusted partner for grid operators and utilities.
    • End-User Segments Addressing: Beacon Power serves utility companies, independent system operators (ISOs), and grid operators seeking frequency regulation and grid stabilization solutions. Their flywheel systems are deployed in grid-connected installations, ancillary service markets, and renewable energy projects, providing dynamic energy storage and grid support capabilities.
  3. Stornetic:
    • Technology Enhancement: Stornetic develops innovative flywheel energy storage systems for various applications, including renewable energy integration, microgrid support, and industrial energy management. Their flywheel systems feature advanced composite rotors, magnetic bearings, and control electronics for efficient energy storage and release. Stornetic’s proprietary flywheel technology offers high energy density, rapid response times, and low maintenance requirements.
    • Uniqueness of the Startup: Stornetic stands out for its focus on next-generation flywheel technology, emphasizing performance, reliability, and sustainability. Their flywheel systems are designed to address the challenges of intermittent renewable energy generation and grid instability, providing scalable and cost-effective energy storage solutions. The company’s commitment to continuous innovation and collaboration with industry partners positions them as a leading provider of flywheel energy storage solutions.
    • End-User Segments Addressing: Stornetic serves a wide range of industries and applications requiring energy storage solutions, including renewable energy integration, grid stabilization, and industrial automation. Their flywheel systems are deployed in utility-scale projects, microgrids, and industrial facilities seeking reliable and high-performance energy storage solutions.

Sample Research At Top-Tier Universities

  1. University of Texas at Austin:
    • Research Focus: The University of Texas at Austin is a pioneer in the field of Flywheel Energy Storage, focusing on the development of advanced materials, mechanical designs, and control systems for high-performance flywheel energy storage systems.
    • Uniqueness: Their research involves designing flywheel systems with optimized rotor configurations, magnetic bearings, and vacuum enclosures to minimize energy losses and maximize energy density. They also explore innovative composite materials, such as carbon fibers and graphene, for enhancing the strength, stiffness, and fatigue resistance of flywheel rotors.
    • End-use Applications: The outcomes of their work have applications in grid stabilization, renewable energy integration, and uninterruptible power supply (UPS) systems. By providing fast response times, long cycle life, and high efficiency, flywheel energy storage enables reliable and resilient electricity supply in both grid-connected and off-grid applications.
  2. Sandia National Laboratories:
    • Research Focus: Sandia National Laboratories conducts cutting-edge research on Flywheel Energy Storage, leveraging its expertise in electromechanical systems, energy storage technologies, and grid integration to develop next-generation flywheel systems for diverse applications.
    • Uniqueness: Their research encompasses the development of novel flywheel designs, including composite rotors, magnetic bearings, and integrated power electronics, to enhance energy storage capacity, power density, and reliability. They also investigate advanced control algorithms, fault-tolerant architectures, and safety mechanisms to ensure the safe and efficient operation of flywheel systems in dynamic grid environments.
    • End-use Applications: The outcomes of their work find applications in microgrids, electric vehicles, and aerospace systems. By advancing flywheel energy storage technology, Sandia National Laboratories’ research contributes to enhancing grid stability, reducing fossil fuel dependency, and promoting the adoption of clean and resilient energy solutions.
  3. Imperial College London:
    • Research Focus: Imperial College London is at the forefront of research on Flywheel Energy Storage, focusing on developing innovative flywheel designs, materials, and control strategies for addressing the technical and economic challenges of energy storage integration in modern power systems.
    • Uniqueness: Their research involves investigating flywheel systems with novel architectures, such as hybrid bearings, superconducting magnets, and cryogenic cooling, to improve energy efficiency, operational flexibility, and scalability. They also explore applications of flywheel technology in niche markets, such as space propulsion, kinetic energy recovery systems (KERS), and energy harvesting.
    • End-use Applications: The outcomes of their work have applications in renewable energy grid integration, frequency regulation, and electric transportation. By pushing the boundaries of flywheel technology, Imperial College London’s research contributes to enhancing energy security, reducing carbon emissions, and fostering innovation in the global energy transition.

commercial_img Commercial Implementation

Flywheel energy storage systems are commercially available and are being implemented in various applications, including:

  • Frequency Regulation: FES systems are used by grid operators to provide fast-response frequency regulation services, helping to maintain grid stability.
  • Voltage Support: FES systems can provide voltage support to the grid, improving power quality and reliability.
  • Uninterruptible Power Supplies (UPS): FES systems are used in UPS applications to provide backup power in case of grid outages, ensuring critical equipment remains operational.
  • Industrial Applications: Flywheels are used in some industrial applications, such as regenerative braking systems for cranes and other heavy machinery, to recover and store energy.