Why the Future of Energy Storage is Spinning To Make a Comeback

Flywheel energy storage systems (FESS) are experiencing a resurgence as a viable solution for renewable energy storage, moving beyond their traditional role in grid frequency regulation. Advances in engineering have extended the discharge duration of these systems from mere seconds to several hours, enabling them to store excess renewable energy and release it when needed. Amber Kinetics, a leading company in this field, has pioneered this leap with flywheels capable of four-hour discharge periods, positioning the technology as a serious contender in the transition to renewable-heavy power grids. The core technology relies on a solid steel rotor that spins at high speeds within a near-perfect vacuum, levitated magnetically to minimise friction and energy loss. This design overcomes the limitations of earlier flywheels, which suffered from rapid wear and short cycle life due to mechanical friction and heat. Unlike chemical batteries, flywheels do not degrade over time with repeated use, offering a lifespan of around 30 years and consistent performance, which is particularly advantageous in tropical climates where heat can accelerate battery deterioration. Amber Kinetics has strategically located a production facility in the Philippines, near the author’s home city, reflecting the suitability of island grids with high renewable penetration for kinetic energy storage. The company’s systems have already been deployed in various locations worldwide, including Hawaii, Japan, and parts of the United States, demonstrating resilience even under extreme conditions such as earthquakes. This geographic diversity highlights the growing recognition of flywheels as a robust and adaptable energy storage solution. The implications of this technology extend beyond mere innovation; it offers utilities and grid operators a predictable, long-lasting, and low-maintenance alternative to lithium-ion batteries. As renewable energy adoption accelerates globally, the ability to store and dispatch energy reliably will be crucial, and flywheels could play a pivotal role in stabilising grids while reducing dependence on chemical storage. The continued scaling of production and deployment will be key to determining how widely this technology can be integrated into future energy systems.