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Velkess flywheel technology promises cleaner, more efficient energy storage


April 16, 2013

Bill Gray is looking to the past to reinvent the future of energy storage with a new take on the spinning flywheel

Bill Gray is looking to the past to reinvent the future of energy storage with a new take on the spinning flywheel

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It's no secret that the successful future of wind, solar and other renewable sources hinges on the development of cost effective energy storage systems.

Of the technologies currently in play, batteries are still expensive and limited in capacity, compressed air energy storage requires very specific spatial geological formations, thermal storage – often used in concentrated solar power (CSP) facilities – is also expensive and difficult to scale, and pumped storage hydroelectricity, while relatively inexpensive and efficient (70–85 percent), also requires specific geographical locations.

New approaches such as the ability to store energy in molecular bonds are also in development, but entrepreneur and inventor Bill Gray is looking to the past to reinvent the future of energy storage with a new take on the spinning flywheel.

Perhaps the most straightforward storage method of them all, energy storage flywheels have been in use for over a century. A flywheel is usually a heavy shaft-mounted rotating disc that absorbs and stores twisting or spinning motion and then releases it as rotational kinetic energy.

Armed with the pioneering research of John Vance, a retired professor at Texas A&M; University (TAMU), Gray has developed a novel approach to flywheel design with a patent pending flywheel system called Velkess – short for VEry Large Kinetic Energy Storage System. According to Gray, Velkess is a radical improvement on existing flywheel technologies and is dramatically less expensive than even the most economical energy storage technologies available today.

Most existing flywheels are designed and built like the turbines of high performance jet engines. They use materials like carbon fiber composites and precision engineering to exactly control the forces inherent in all spinning rotors. These materials and the required engineering and control methods are extremely costly and not conducive to a low cost energy storage solution.

Gray’s “soft” rotor on the other hand is made of E-glass, operates in a vacuum and flexes in response to destabilizing forces therefore reducing the amount of stored power lost to friction down to about 2 percent on a daily basis. E-Glass or electrical grade glass (used in the reinforcing phase of fiberglass) is not as strong as carbon fiber but can store up to 20 times more energy per dollar. Like a cowboy’s lasso, it gains stability as it rotates and according to the company, the energy on the rotor can be held in complete safety even in the event of power failure or natural disasters like earthquakes.

The existing prototype flywheel floats on a high efficiency magnetic bearing assembly, can make or absorb 2 kW of power, and can store 0.5 kWh of energy. Gray needs to scale that storage capacity up 30 times to 15 kWh. That requires replacing the 25 lb flywheel rotor seen in the video with a 750 lb version.

“Our challenge is with the magnetic assembly," says Gray. "The magnets to float 25 lbs are easy to get on the internet and easy to work with by hand. Magnets strong enough to float 750 lbs, are a different story. They need to be custom made and are too powerful to safely work by hand.”

Gray has successfully raised funds on Kickstarter for the next phase of development which will fund the construction of a magnetic bearing and motor assembly. This is the final piece of the puzzle for the completion of a fully working prototype which would pave the way for demo units which will be used to market the invention to potential buyers.

More technical information about the Velkess flexible flywheel can be found in the Patent Application.

Sources: Velkess, Kickstarter


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.

Alastair Carnegie

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.

Ronald Leard

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

Paul Pierce

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??



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?


Wikipedia has a good synopses of energy storage flywheels- what I remember is larger lightweight was better (slower...)

I'd be thinking sand heat storage- very high temps if its for electricity production (just short of glass temps). check builditsolar- gary has lots of info


Them would need to be some really, really good bearings and not to mention the spiny thing would need to be balanced fairly well also. that being done it is a way to store energy without the use of a battery.

Jay Finke


The dude's name is Gray, not Gates. I know Mr. Gates gets a lot of press, but he's nowhere in this report. :-)

Michael Barreto


When your generating system is down for repair or maintenance and then the power line from your utility also goes down, then "net-metering" is NOT storage. Or, at least, not useful storage.


I'll stick with lifting water, I can either build a water tower or dig a hole. (finding an aquifer would be nice though. I won't take out more than I put in unless I'm properly permitted.)

re; JBar

Your screwed if the lines go down where as storing the energy you are not dependent on the utility.


Though not accepted as reality "yet" free energy will soon be shown to be not only possible but having been around for some time. It's all about modulation, and the standing wave, there is enough energy all around us and bound up in the dimensional boundary layer to power everything. It has saddened me for 30 years to know that the "powers that be" have purposefully withheld, and suppressed this, and other technologies for their own selfish interests. It is time we all find out what we have been missing, if it is not too late already!

Michael York

Using the grid for storage is OK if:-

(a) your property is connected to the grid and (b) net metering (ie where you are credited for what you put into the grid at the same tariff as you are charged for what you use or (c) there is a feed-in tariff option available that actually credits you more per kWh for what you generate than what you use.

Unfortunately, at least here in New Zealand, the power companies are moving to only pay you what they would be paying the major generators so anything you generate more than you use – measured on an instantaneous basis – will earn only about a fifth of the rate that you have to pay for what you are using more than you are generating – again on an instantaneous basis.

So cost-effective efficient energy storage makes sense..

Lindsey Roke

Dear Mr York: Do you have concrete details, or a reference article, please? Best regards...

Daniel Cunningham

I'm sick & tired of hearing about these "just about to happen" technologies and then wait many years, then never - NEVER - EVER see these things come to fruition...not a one of them. This one is particularly deja vu in that it reeks of the year 2000 when Re-Energizer put out an article about Jack Bitterly and his "just about to happen" flywheel. For those of you who don't remember, here's the link http://www.wired.com/wired/archive/8.05/flywheel.html . Bitterly failed and so will our good friend above Bill Gray. It's too bad - the world could really use better energy storage...we'll all have to keep looking though because this will again be a flywheel that won't ever fly.



The idea goes back way further than that. There was a flurry of research on flywheels in the 1970s thanks to the Energy Crisis. Go to Google Books and search for "flywheel energy storage" in Popular Science. There was even a similarly optimistic cover article in 1979. In fact, they have one article from 1946 about an electromagnetic catapult design for aircraft that uses a flywheel, a nearly 7-decade-old predecessor to the EMALS system now under development for next generation aircraft carriers.


The difficulty in building an effective flywheel energy storage system is good bearings with modern magnets it is not that difficult. Vacuum chambers are not that difficult to build. (A hollow fiber reinforced concrete sphere wrapped in plastic.) Electrically add and remove power and make sure you don't overspeed it or the results may be indistinguishable from an explosion. It will be news when somebody starts producing them commercially.


After reading the comments it appears we have a collective of great brains right here. To bad we don't understand how to take that and perpetuate it. I have to ask. is bigger better? Can a lot make a lot? I never hear anyone talking small scale in numbers. For example if my neighborhood of 50 homes all put solar and wind on our roofs would we as a whole make a bigger difference than just one home? I would hope so. Which way would get us there faster. Waiting for the Big one or starting up a bunch of small one ganging as one big one. Just saying.

Scott Kelley

Neodymium (and other rare earth) magnets are more than capable of suspending heavy weight flywheels (and vertical axis wind turbines). The question is: do they belong on the shaft or below the rotating mass?

A composite flywheel turning inside of a vacuum chamber is great but is still only as valuable as its average energy capture and re-contribution (application specific). Friction losses of only 2% are quite good, if scaled-up device exhibits similar characteristics.

While I like the in-ground flywheel idea, I like the idea of an above-ground vertical axis wind turbine coupled to the flywheel in some fashion i.e., directly overhead. Any electricity not used by the building (house) could be sent to the flywheel as either electric power or multiplied rotational energy (or both).


Daniel Cunningham,

You wanted a reference article for Free Energy. I like this one myself... http://www.teslasociety.ch/info/NTV_2011/free.pdf

Larry Hooten

Michael P York, free energy may be possible but it would never be free to deliver that energy, infrastructure and maintenance cost a hell of a lot of money.

Denis Klanac

Use a linked array of proven smaller units rather than one big unproven one.


I also used to have high hopes of a "revolutionary technology right behind the corner" to deliver me and everybody from the current malaise, which would invariably fall flat... and would not "fly" as in this flywheel.

What I understood in the patent application there are two major parts involved: the flexible flywheel and the motor-generator with little inefficiency. Both must be economical to produce.

The first part - flywheel proper has been resolved by the simple self balancing design and low cost materials. That was where all the previous dreams did not fly: all other relied on high precision hight strength exotic material (nanotubes). First part solved.

The second part is "just" to customize the current existing technology to exact specs for this application. This is where it still could fall flat on its face...but it looks like it is solvable.

Once they have a prototype that is cheap to make yet performs to the expectations (and if not for a major marketing disaster and incompetency) short of evil forces intervening (all those conspiracies out there some others speculated above as reason for no free energy available now) ...this should fly!

You can do the resin flywheel part D.I.Y yourself if you wish, the vacuum is not that difficult to make either...just the pesky motor-generator (plus system integration - controllers..) if you have time on your hands you are set. Good somebody out there at least trying.

Keep the hopes high. That is "Why Success Always Starts with Failure!"


A couple of thoughts:

The use of expensive, difficult-to-handle magnets as anti-friction bearings seems unnecessary. Overall efficiency of the unit, which includes the real production costs, would likely be improved using a more common approach.

Large flywheels are used extensively already in many commercial industries. The interesting thing about this design approach is the (apparent) reduction of engineering and production tolerances needed to manufacture a workable unit.

Pumping electricity back onto the grid from house-mounted solar panels is one of those things that sounds great until one considers all the unintended consequences of it. A market, free to find it's own ideal efficiency, would never evolve such a useless beast. Only in our world, where 3rd party mandates (i.e. governmental regulations) pick winners and losers, does such a system even exist.

My personal favorite form of energy storage is completely natural. Solar energy is converted into biological mass, which when compressed using the natural forces at work in the bottom of a gravity well, converts into an abundant, high density, and readily usable form of energy. This form of energy is highly stable for long periods of time and can be readily converted back into usable energy with just a little know-how.


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