Abstract: A kinetic energy storage system utilizes a flywheel with a motor generator to store energy. A flywheel rotor is located in an elongate housing which forms at least part of a rigid framework. In use on a vehicle, the framework provides a chassis for the vehicle and the vehicle may be powered from the flywheel. The flywheel rotates at high speed in a vacuum and the motor generator could be an inverted switched reluctance motor generator optionally providing a magnetic bearing function.