The coupling of thermal units with flywheel energy storage system can effectively improve the frequency regulation performance of AGC, solve the problems of long response time, slow climbing rate and low regulation accuracy of thermal units when tracking AGC commands, and. . The coupling of thermal units with flywheel energy storage system can effectively improve the frequency regulation performance of AGC, solve the problems of long response time, slow climbing rate and low regulation accuracy of thermal units when tracking AGC commands, and. . Flywheel systems provide very fast response, high power density, and long cycle life, but generally only store energy for seconds to minutes. As such, they are best treated as high-power assets for frequency regulation, inertia emulation, and short bridging, rather than as long-duration energy. . Flywheel energy storage technology generates revenue by providing various services, primarily to power grids, industrial applications, and renewable energy integration. Cost-effective energy storage, 3. North America dominated the market and accounted for a 38. This article explores their operational principles, real-world applications in renewable integration, and emerging market opportunities supported by global case studies and technical data. 2 billion by 2030, with a CAGR of around 8-10% from 2024 to 2030. Flywheel energy storage systems (FESS) store kinetic energy through a rotating mass and release it instantly when required. .