The design and development of a low cost 0.71 KW-HR energy storage flywheel to provide 100 KW for 15 seconds is described. The flywheel target market as related to the selection of the power and duration for the flywheel is also defined. The key subsystems in the flywheel system are described to show how the flywheel system is successfully integrated into a mechanical system. Test results are then presented. The flywheel is designed for high power, short discharge applications in the UPS and power quality markets. It can output up to 100 KW for a 15 second duration, targeting diesel generator set (gen-set) ride through applications as well as load leveling applications. The flywheel operates at a peak speed of 35,000 rpm, pulling power down to a minimum speed of 20,000 rpm. The tests conducted on the system have verified expected peak power output, energy storage capacity, maximum operating speed, and steady state thermal performance.