by Chad Redman
Rapidly spinning masses known as flywheels are used for energy storage in a wide variety of applications, including transportation, sport, and grid level electricity. Focusing on grid solutions, flywheel energy storage systems (FESS) comprise massive rotors magnetically suspended in a stator, which acts as a motor when the flywheel needs to be spun up and a generator when the kinetic energy of the flywheel needs to be converted into electricity. Through the use of magnetic bearings and a vacuum chamber for the flywheel housing, FESS are highly efficient for short-term energy storage.
FESS have a set a characteristics that make them very effective for specific applications, but impractical for operations at the largest scale. These flywheels produce very high power electricity, capable of doing work quickly. However, they do not store tremendous volumes of energy, so they are best suited to feed applications that require high power but low energy. Moreover, FESS can be run through well over 100,000 cycles of full charge-discharge, giving them better longevity than most energy storage technologies and making them a fitting solution for high frequency processes. This advantage is further supported by the quick ramp rates of FESS; flywheels can achieve full energy storage in a matter of seconds if excess power becomes available. Unfortunately, while this high-tech solution is an environmentally sound option for energy storage, it is also highly expensive relative to competing substitutes.
“Flywheels.” EnergyStorage.org. N.p., n.d. Web. 16 Feb. 2015.