Flywheel Energy Storage System

The importance of energy storage devices has been increased due to the demand of using energy more efficiently as peoples are getting more concerned about the resource or environmental problems. For example, the surplus energy from windmill electricity generation should be stored to somewhere; otherwise, the energy will be just wasted.

Flywheel energy storage systems are one of energy storage devices. They are nothing but rechargeable batteries. They store energy mechanically in the flywheel rotor by rotating the rotor while as chemical batteries stores energy electrically. When we want to use the stored energy in the rotor, a generator is used to convert mechanical energy to electrical energy.

Since the flywheel system is a very efficient energy storage device, it can be used for various applications. Hybrid electric vehicles could be one example of flywheel applications. Hybrid vehicles contain an power unit such as internal combustion engines and electric motors and an energy storage unit such as flywheels or chemical batteries. When vehicles are cruising at a constant speed like 60 mph, relying on only internal combustion engines can be sufficiently efficient way. However, when we need to accelerate vehicles, internal combustion engines tend to use more fuel than needed. Therefore, if we use both internal combustion engine power and auxiliary power from flywheels or chemical batteries, we can save considerable amount of energy to get to a certain speed. Currently, chemical batteries are usually used for hybrid vehicles, however, flywheel systems can substitute chemical batteries for the following reasons.

Flywheel systems are not sensitive to temperature since they are operating in a vacuum containment. Therefore, the hybrid vehicle with flywheel systems can run without any problem at very cold or hot areas. And, flywheel systems can store more energy per system weight compared to chemical batteries, which enables the hybrid vehicle to have more space and less weight while performing same as the hybrid vehicle with large size of chemical batteries.

Besides hybrid vehicles, there are many applications which need more efficient energy storage devices such as flywheel energy storage systems as in the following figure.

(Many applications for flywheel energy storage systems)