Comments on: Now on Kickstarter: a new kind of spinning energy storage device

By: Jan Janse Van Rensburg

Jan Janse Van Rensburg — Thu, 09 May 2013 07:45:15 +0000

I have personally (Together with a research group at the north west university in Potchefstroom South Africa) also developed a Flywheel Energy Storage System that was suspended on active magnetic bearings (FLY-UPS was it’s nickname). Flywheel energy storage has a number of advantages over classical energy storage, but one of the problems is that for a flywheel to be efficient and small you need high rotational speeds and very low losses. Using a flexible disc would certainly enable high speeds but even when using a vacuum to minimise losses the heat generation and associated losses of the bearings can not be ignored. But kinetic energy storage certainly has a future especially in green-energy fields.

By: Carl Stewart

Carl Stewart — Tue, 07 May 2013 23:56:37 +0000

It would be very interesting to see a group of units would do? If you have a multiple of these storing as much power as to be able to use for high energy Ion propulsion for future use in our spaceships as an alternative instead of liquid propulsion.
I believe Gray is onto something!
Thanks for the post,
Carl,

By: Brandon Williams

Brandon Williams — Tue, 07 May 2013 15:32:49 +0000

My company uses Nickel Iron batteries for energy storage. One of the biggest problems with the flywheel is the moving pieces.

When you compare wind energy to solar energy, solar is a better option over the long-term because it requires no maintenance.

Flywheels will definitely require ongoing maintenance, which must be taken into account when calculating $ per Amp hour over time.

For more information on energy storage that works today, check out Iron Edison batteries.

By: Bill Gray

Bill Gray — Wed, 13 Mar 2013 17:09:50 +0000

Hog2Hog has it just right. The big advantage of the flexible flywheel over the rigid flywheel is that it can be made dramatically less expensively.

The cowboy’s lasso is a highly stable and very well controlled rotor system. A jet turbine is also a stable and very well controlled rotor system. These two examples take two very different approaches to the same goal… a stable well controlled rotor. It just turns out that making lasso is a lot cheaper and a lot more forgiving than making a jet turbine.

Beacon’s flywheels were indeed made of CFRP (Carbon Fiber Reenforced Polymer) and it is true that carbon fibers are available that are 6x to 8x stronger than e-glass per kilogram.

But what is important here is that “e-glass” fiber glass is 10x to 20x stronger per dollar. Which is to say, if you spend $100 each on e-glass and carbon fiber you can hold 10x to 20x more weight on the e-glass you purchased than the carbon fiber you purchased.

The same is true for the amount of energy you can store on the fiber when you make it into a flywheel. E-glass will store 10x to 20x more energy per dollar than carbon fiber.

Velkess flywheels are very capable of the high power applications that flywheels are traditionally applied to, but because we can make a safe stable flywheel so much more inexpensively, we are more focused on the long duration applications that have far wider application.

On a Velkess system, the link between the rotor and axle is actually very strong. Flexible, but also very strong! While we haven’t focused on “pulsed power” type applications that would require massive acceleration and deceleration, we have run some experiments where a fully charge flywheel is brought to a stop in about 15 seconds. The rotor-axle link performs just fine.

Bill Gray

By: D. Rob

D. Rob — Mon, 11 Mar 2013 20:08:26 +0000

I thought the same thing. “lasso vs. a jet engine” is like saying “a chair to a soap dish”.

By: archonic

archonic — Thu, 07 Mar 2013 16:53:37 +0000

The way I understand it, this is conceptually like a CVT built inherently into a flywheel design. I forget the name of it, but there was a very large grid scale underground flywheel with lots of government funding that ran for a few years. It eventually flew apart and the project was shut down. If this guy can build a conceptually better fly wheel with crowd sourcing and bicycle parts, that will be hugely embarrassing to anyone that was associated with that government project.

By: Christian Wiesner

Christian Wiesner — Tue, 05 Mar 2013 21:48:04 +0000

BEACON Power’s flywheel rotors are not made from steel, but from CFRP fibres. Those are 6x to 8x stronger than fibre glass, but admittedly their Achiless heel is the low binding force from one fiber to the next, through the resin. At higher velocities, the growing tension within the rotor will lead to delamination of the CFRP layers, and destroy it, and this will happen much earlier before the maximum strength of the (expensive) CFRP fibres will be reached. BEACON are holding a number of interesting patents to prevent this, e.g. by varying the winding strength of the CFRP fibres during production of the rotor, going from low to high from inner to outer.

The problem i can see with the design of Mr. Gray is the rather weak linking of his rotor to the axle. Flywheels, traditionally, have been used for high power applications like frequency control and peak compensation, as this is where they outperform any other storage technology.

However, this will require that the rotor can be accelerated, and later braked down with rather high forces, otherwise the high loading powers can’t be realized. Looking at the pics above, i have rather big doubts if that bundle of fibres will be able to transmit strong forces to the axle and the motor ?

Christian Wiesner
ROTOKINETIK UG (in foundation), Germany

By: hog2hog

hog2hog — Tue, 05 Mar 2013 21:04:06 +0000

In my understanding, a flexible flywheel is not only significantly cheaper but, being flexible, it is able to self stabilize and remain stable in an unstable environment. So there is the lasso analogy. Even though the cowboy is bumping up and down on the horse, the hoop of the lasso maintains a steady spin. this means that a flexible flywheel in a vacuum can maintain its spin and not wobble or loose energy if the container gets knocked around. it also means that over time, any warping or wear of the material won’t be as damaging to the spin and storage capacity as if it were a rigid flywheel.

I’m not the inventor but am familiar with his product.

By: Derek Jensen

Derek Jensen — Tue, 05 Mar 2013 01:41:55 +0000

Until he explains how a flexible flywheel can be better than a rigid flywheel, there’s no there there. It’s like “a jet engine vs a cowboy lasso”? How is that any kind of comparison?