The objective of this work is to investigate, from both experimental and simulation points of view, the feasibility of a flywheel energy storage system (FESS) for buffering energy when implemented in off-grid (autonomous) electricity production. Toward this aim, a prototype FESS was built and measured to identify its optimal design and operational characteristics as they have been obtained theoretically. After simulating two different materials and shapes for the rotating mass, the hollow aluminum cylindrical design found to provide excellent energy storage results. By identifying the storage capacity of a prototype laboratory-scale FESS, it is also found that such a device can be promoted as a UPS system to cover peak loads during limited time periods. Finally, the scale of the project found to be a crucial parameter for its feasibility.