Maybe Bill Gray should drop the idea of fancy magnets? Make the bearing large! and use regular though high performance magnets. Adding active weight is hardly a disadvantage after all. The magnetic bearings could also double up as three-phase motor-generator. AC-DC-AC conversion by MOSFET units, similar to those used on railway trains. There is no need for laminated iron cores, as 'crenellated' coreless copper windings could do the job. The 'up' wire has N/S magnetic polarity, reinforced by the 'down' wire S/N polarity. Current induced by Flemming's right hand rule for motors. (and vica-versa for Magneto-Alternator)
The 'crenelated' windings would need to be on two levels, and phase staggered. Both continuous stator rings would support the load. The two rotor rings would need equal spaced gaps. |_| |_| |_| |_| etc. The lower ring magnets equally spaced where the gaps were located in the upper rings.

Allowing the flywheel to find an axis somewhat independent of the disturbances (like a washing machine drum) still does not get over the fact large amounts of energy are stored in the moving mass.
The upper limits of flywheel storage are found with one that is specially profiled so that the stress is the same everywhere, and breakup is near the point bits of the periphery are about to break away.
Also. extracting significant torque off that long thin shaft gives a classic buckle stress. If this gets loose, it had better be in the ground somewhere!

Off the shelf parts, with a horizonal shaft , enclosed bearing boats. ease of placement. extreem weights. Lower cost, larger weights, easy built on site of concreat wheels. Using off the shelf automotive torque converters. KISS is the way to go.

Some efficiency might be gained if it is operated in a vacuum to remove air drag resistance.

Why have a wimpy spindle as output? Use coils and take electrical energy off, same as is added. Also use wind energy to add additional energy electrically or direct.

Reviewing the patent application one is challenged to see any significant improvement over existing art.
There are obvious ways to overcome the magnet and suspension problem based on the unique characteristics of an electrical energy storage system. Properties Gray fails to recount and utilize in his application.
The answer is there Bill keep looking. Good luck in the hunt.

it;s a good idea to have the equivalent of 41 lbs of gunpowder outside your house??
wle

maybe Alastair should patent his idea...

How is my "net-metering" not energy storage. When my 5 kw (peak) solar array generates more than my unoccupied house is consuming, my electric meter tracks the excess and credits the power that was pushed back into the grid. What Bill Gates is really trying to accomplish here is renewable energy off the grid. Why spend money on redundant infrastructure...just run a powerline to your cabin and you have your energy storage. Surely Bill can find better things to spend his money on...say...developing an intuitive and easy to use operating system??

JBar, it's not everywhere that you can sell the energy back to the grid, you know?