Thesis (M.S., Electrical and Computer Engineering)--University of Idaho, June 2014 | To support human colonization and exploration of the lunar surface, NASA needs a way to store energy generated by various possible sources to meet demand that varies with the time of the lunar day. Flywheels provide a reliable, efficient and low-maintenance way to provide continuous energy on demand. In general, a Flywheel Energy Storage (FES) system includes an electric machine to convert between mechanical and electric energy, power electronics to provide an interface between the machine and the electric distribution and generation system, and a flywheel to store energy. This thesis investigates and designs an integrated hubless flywheel and electric machine designed for low rotational speeds. To properly predict the response of the FES system to external imbalances, a dynamic model of the integrated system is developed in this thesis. The dynamic model is useful in developing the control algorithm for the FES system.