Flywheel power storage

A recent innovation in electrical energy storage is the use of flywheels.

A typical system consists of a flywheel? disc, usually made of [carbon fiber]?, suspended by [magnetic bearings]?, inside a vacuum chamber, connected to a combination motor?/generator?.

The system stores power by driving the motor to increase the speed of the spinning flywheel. The system provides power by using the momentum of the flywheel to power the generator.

Flywheel power storage systems in current production (2001) have limited storage capacity and fast discharge rates. They are mainly used to provide load-leveling for large battery systems, such as an [uninterruptable power supply]?.

There is ongoing research to make flywheel systems smaller, lighter, cheaper, and have a greater capacity. It is hoped that flywheel systems can replace conventional chemical batteries for mobile applications, such as for electric vehicles. Proposed flywheel systems would eliminate many of the disadvantages of existing battery power systems, such as capacity, charge time, and weight.

One of the primary limits to flywheel design is the [tensile strength]? of the material used for the disc. Generally speaking, the stronger the disc, the faster it may be spun, and the more energy the system can store. (Insert formula for angular momentum here.)

Further improvements in superconductors may help eliminate [eddy current]? losses in existing magnetic bearing designs.