First-generation flywheel energy-storage systems use a large steel flywheel rotating on mechanical bearings. Newer systems use carbon-fiber composite rotors that have a higher tensile strength than steel and can store much more energy for the same mass.OverviewFlywheel energy storage (FES) works by spinning a rotor () and maintaining the energy in the system as Most. A typical system consists of a flywheel supported by connected to a. The flywheel and sometimes motor–generator may be enclosed in a to reduce fricti. Compared with other ways to store electricity, FES systems have long lifetimes (lasting decades with little or no maintenance; full-cycle lifetimes quoted for flywheels range from in excess of 10, up to 10, cycles. In the 1950s, flywheel-powered buses, known as, were used in () and () and there is ongoing research to make flywheel systems that are smaller, lighter, cheaper and have. Flywheels are not as adversely affected by temperature changes, can operate at a much wider temperature range, and are not subject to many of the common failures of chemical. They are also less p.
