With the ever-increasing demand for energy, we have to focus our attention on greener alternatives. The main problems with non-conventional energy sources are that they need storage. Flywheel batteries seem to solve this problem to a great extend. Flywheel energy storage systems are non-polluting; need no replacement and little maintenance. The basic working of flywheel batteries and their applications are discussed in brief. Flywheel batteries stores energy as rotational kinetic energy of the flywheel and this energy can be retrieved either through direct mechanical or electrical translation..