[jyl]

Originally Posted by Pazuzu

You are correct, the weight won't do any work at all because there is no exchange of it's potential energy to kinetic energy.
The "mechanism" that is holding it is doing all of the work, so if the wheel rolls, you're having to put that energy into that mechanism somehow. Either winding a spring, or burning fuel or something.

If you don't do that, the wheel won't turn.

The idea is a battery in the wheel that powers this mechanism. What the mechanism is, no idea. Probably something like a solenoid. But it could be a hamster on EPO.