Yes, a flywheel UPS system could be an effective solution.
Flywheels store kinetic (motion) energy by using the inertia of a spinning wheel. Because storage capacity is largely determined by wheel size and speed, a flywheel with a small mass can store a significant amount of energy if the wheel has a large diameter and it's spinning very fast. That eliminates the space and maintenance needs of battery energy storage.
Flywheels only provide energy storage for about 15 seconds. However, when properly integrated and maintained, standby generators can reliably support the critical load in 10 seconds or less, providing adequate switchover time. The capacity of a flywheel is dependent on load, according to Active Power, Inc. For example, at 100 percent load, standard ride-through time is 14 seconds, while at 25 percent load, a flywheel can supply up to 52 seconds of backup power.
Flywheel UPS systems are recommended for three-phase critical power applications requiring the highest efficiency and reliability. Generally, battery UPS systems are a better fit for:
- Single-phase 120/208 VAC applications
- Smaller, three-phase applications
- Extended run-time operations of five minutes or more, where there's no backup generator available
- Facilities with backup generators that may not start reliably
Although they may cost more, flywheel systems are rugged, environmentally friendly and expandable—all of which help to lower total cost of ownership.
Image source: U.S. Department of Energy