5. General conclusions

The market for secure power supplies (UPS, etc.) is a key outlet for electrical energy storage systems. In this market, electrochemical batteries (Pb-acid, NiMH, NiCd...) have a dominant position; however, for the past ten years or so, European and American companies have been offering inertial electrical storage systems (SISE) with excellent performance thanks to several types of flywheel generation.

Flywheels are complex components, especially for high-speed flywheels, involving very different technologies: the flywheel itself, which requires a great deal of attention to manufacture in composite materials, the bearing system, the electrical launch and energy recovery system, the vacuum enclosure, heat exchange and safety.

Inertial electrical storage systems offer a number of advantages:

• flywheel...