Calculation for mech. Storage System

I'm looking for a Mechanical Engineer who can make a calculation for a mechanical position energy storage system I have in mind. An Electric motor to lift up a very heavy weight up some meters and get the energy back later when using the motor as a generator (recuperation like in an electric car). I have made a 3D drawing (in Vectorworks) with that kind of clockwork - and it would be interesting to know how much energy it can store with different parameters and what improvements could be made. Or if other kinds of transmissions or pulleys would do a better job than gears in steel.
The footprint would be about that of a car or 2, the height up to 12 meters