You may find some important information in this article.

another useful article for your purpose.

Thank you.

A flywheel is a simple mechanical device that stores enerty in kinetic form, proportional to it's Inertia and speed. The inertia determined by shape, diameter and mass. One can change any of these parameters to change storage, within the material and safety limits, of course.

My concern with metalic flywheels is that they store large quantities of elastic energy in the material and are dangerous on disintegration. For this reason I've worked exclusively with high speed composite flywheels, where the energy is almost entirely absorbed by the disintegration process of the composite material. The manufacturing is quite different, however, the mechanics are the same.

There are some publications, dealing with flywheel storage, which you may find of value, linked to my profile.

Thank you all for your answers.