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A Beacon employee stands next to a complete flywheel storage system. Each system features 10 flywheels and can store enough electricity to provide 1 MW of power for 15 min (250 kWh).  (Source: Beacon Power)

Beacon Power plans on offering 20 MW (5 MWh) units to utilities for back up power and demand levelling purposes.  (Source: Beacon Power)
Volatile energy market fuels demand for energy storage

Rising gas prices haven't just been spurring the automotive market to change, they've also been taking their toll on utility companies, who have struggled with the tradeoffs of raising prices and customer dissatisfaction.  Now creative thinkers at Beacon Power, an interesting startup, have a solution that just might help utilities out.

Beacon Power produces a novel form of power storage in the shape of large carbon fiber flywheels, which spin at 16,000 revolutions per minute -- a surface speed of about Mach 2.  At one meter in diameter and 8,000 lbs, each wheel can provide 100 kilowatts of electricity for 15 minutes.

The company, led by CEO William Capp, is packaging 10 of the flywheels together to give an impressive power output of 1 MW and energy storage capacity of 250 kilowatt hours.  With the average household consuming approximately 8,900 kWh yearly, this would be enough to power a home for over 10 days.

The new technology isn't just about the high energy costs, either -- it can help provide backup power in case of a storm.  Utilities and businesses could adopt the devices to minimize interruptions to customers during storms or brownouts. 

On the environmental side of things, the device could complement intermittent power sources such as wind power and solar power, and use their stored output to avoid incurring extra cost or outages during periods of peak demand.

Says Capp, "These are used for fine tuning to keep everything in balance. The way it's done today is that a dispatcher sends a signal to generators...to increase or decrease output."

The device is extremely simple on a most basic level.  Adding electricity spins the wheel faster.  At any time this spin can be converted via a generator to power.  Over time, the wheel slows, but this is a very gradual process.  The technology is among the novel storage technologies being considered for use with alternative energy products.  Another promising technology is molten solar power, which stores solar heat in a briny fluid, for power production in nighttime hours.

However, the flywheels are more promising in a way, in that they can deal with daytime peaks as well.  Capp says that utilities will buy them to help them fulfill emissions restrictions regulations stating, "Rather than generating the power using fossil fuels, we'll be recycling the energy."

The company is marketing plans currently for 20 MW storage facilities, consisting of 20 one megawatt units.



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Carbon Fiber?
By lukasbradley on 6/18/2008 9:36:16 AM , Rating: 2
Any ideas as to why they are made of carbon fiber? Does it have something to do with resistance to static charge?




RE: Carbon Fiber?
By masher2 (blog) on 6/18/2008 9:44:35 AM , Rating: 4
Strength, I would imagine. The centripedal force on the edge of a 4 ton wheel spinning at Mach 2 is tremendous.


RE: Carbon Fiber?
By aBott on 6/18/2008 9:48:27 AM , Rating: 2
Yay! You said centripetal and not centrifugal!


RE: Carbon Fiber?
By rdeegvainl on 6/18/2008 12:11:22 PM , Rating: 5
RE: Carbon Fiber?
By Pudro on 6/18/2008 3:57:05 PM , Rating: 3
I really don't get what is so wrong with talking about centrifugal force. It is a real thing - it just only exists in a rotating frame of reference and it doesn't fit the strictest definition of a "force".

It's just a term that simplifies discussing and calculating physics. There are so many different ways this is always done in physics, yet centrifugal force is the only one to catch all of the crap. I guess it makes people feel smart or something.

Why doesn't everyone get all uppity when a space-related article mentions astronauts in "zero G" or "weightlessness"?


RE: Carbon Fiber?
By wordsworm on 6/18/2008 5:48:00 PM , Rating: 2
quote:
Why doesn't everyone get all uppity when a space-related article mentions astronauts in "zero G" or "weightlessness"?


Maybe it's because if everyone said 'free fall' nobody would want to become an astronaut?


RE: Carbon Fiber?
By djc208 on 6/18/2008 9:47:03 AM , Rating: 3
It's usually due to issues with the integrity of the rotor. At 16,000 rpm the centripital force is huge and the rotor wants to fling itself apart, at which point it would become shrapnel. So making sure the rotor can withstand the spin is vital.

Plus I'm sure it sounds cooler than saying they've attached a bunch of metal disks to a motor/generator then asking for a couple of hundred grand each.


RE: Carbon Fiber?
By Adonlude on 6/18/2008 2:01:14 PM , Rating: 3
Wow, I had no idea that capacitors such as this even existed. Storing energy as kinetic motion instead of simply setting up E or B fields (capacitor or inductor, but almost always capacitor) is quite novel.

The biggest factor must be heat loss in whatever kind of "bearings" this disk or its shaft is rotating on. They must have spent tons of time determining the perfect mass/RPM ratios to get the highest efficiency out of the "bearing" system. Apparently they came up with a very high RPM that required a light, strong material like carbon fiber that wouldn't fly apart. Very cool!


RE: Carbon Fiber?
By kenferg1 on 6/18/2008 7:15:32 PM , Rating: 2
There was an engineer a few years ago that used a small gas turbine coupled to a flywheel sealed in a vacuum. The turbine generated electrical power that spun the flywheel. The flywheel stored the energy in order to release it on demand to a generator that drove the wheels. He had backing from financiers but had issues with the vacuum contained flywheel. It was cool technology, but never got off the ground.


RE: Carbon Fiber?
By ElFenix on 6/19/2008 1:18:28 AM , Rating: 2
it's not a capacitor. it's a big spinning wheel. they're used all over the place. those roller coasters that launch from a dead stop rather than being pulled up a hill typically use flywheels to build up the energy used to launch the coaster. one of the car companies (i think chrysler) was experimenting with a flywheel hybrid back in the mid 90s.


RE: Carbon Fiber?
By Hawkido on 6/20/2008 12:50:52 PM , Rating: 2
quote:
I had no idea that capacitors such as this even existed.


See Landini Tractor:

http://en.wikipedia.org/wiki/Landini_%28tractor%29

Flywheels have been used to store energy between engin strokes all the way back to the steam engine.


RE: Carbon Fiber?
By drank12quartsstrohsbeer on 6/18/2008 9:54:45 AM , Rating: 2
fatigue resistance, most likely.

hopefully those closed containers mean that they pull vacuum on those containers when the wheels are spinning.


RE: Carbon Fiber?
By mattclary on 6/18/2008 10:04:10 AM , Rating: 2
That's a really good question. It seems like you would want a wheel with lots of mass. It would take more power to spin up, but once it gets to speed will take longer to slow down.


RE: Carbon Fiber?
By masher2 (blog) on 6/18/2008 10:12:09 AM , Rating: 3
From eyeballing the units, I would imagine the flywheel itself is made of carbon fiber, but is internally lined with lead or some other dense material. Otherwise, I don't see the volume being large enough to contain a four ton flywheel, along with all the other necessary apparatus.


RE: Carbon Fiber?
By codeThug on 6/18/2008 6:23:10 PM , Rating: 2
If it's spun fast enough can it fold space?


RE: Carbon Fiber?
By Mitch101 on 6/19/2008 10:24:00 AM , Rating: 2
Possibly however if you conected a bunch in series and they spin at 88MPH you travel back in time.


RE: Carbon Fiber?
By bohhad on 6/22/2008 2:14:59 AM , Rating: 2
only if it can feed 1.21 jigawatts to the flux capacitor


RE: Carbon Fiber?
By guacamojo on 6/18/2008 10:23:38 AM , Rating: 2
What's really needed is high strength and high rotational inertia, not mass per se.

The formula for energy stored in a flywheel is 1/2 I w^2, where I is the inertia of the wheel, and w is the rotational velocity (radians per second, although you can convert that to RPM easily enough.) So the inertia is important, but the speed is even more so, because of the squared term.

Carbon fiber has among the highest strength to weight characteristics of modern materials (okay, diamond is better ...) so that alone means that you can spin the hell out of the flywheels.

Most flywheels have a thick rim and relatively thin spokes connecting to a central bearing hub. These flywheels may or may not have a center hub, depending on how the support bearings are set up. They could be running gas bearings on the rim itself, maybe on the OD, where they would naturally put a compressive stress on the rim and act to help hold it together at speed.

Interesting technology.

On a side note, I remember flywheels like this (but smaller and faster) being proposed for automotive applications. There were some really interesting problems to tackle with precession (a 20k rpm flywheel makes a hell of a gyroscope... picture a car that won't turn or pitch up and down...)


RE: Carbon Fiber?
By Solandri on 6/18/2008 1:02:14 PM , Rating: 2
quote:
The formula for energy stored in a flywheel is 1/2 I w^2, where I is the inertia of the wheel, and w is the rotational velocity (radians per second, although you can convert that to RPM easily enough.) So the inertia is important, but the speed is even more so, because of the squared term.

Well, moment of inertia (inertia of rotating bodies) goes as m*r^2 for a thin ring, so the radius of the thing is just as important. IIRC, tension in a thin rotating ring is proportional to the centripetal force, which goes as v^2/r. So tension increases in proportion with rotational velocity (and energy), but actually decreases the more you increase the radius. So the best design direction to maximize energy but minimize forces is to maximize radius.
quote:
Carbon fiber has among the highest strength to weight characteristics of modern materials (okay, diamond is better ...)

Diamond is better in compression, but not in tension. This is true of pretty much any ceramic or crystal.
quote:
On a side note, I remember flywheels like this (but smaller and faster) being proposed for automotive applications. There were some really interesting problems to tackle with precession (a 20k rpm flywheel makes a hell of a gyroscope... picture a car that won't turn or pitch up and down...)

Just install two counter-rotating gyros. Their angular momentum cancels out, and you're left with just their mass. Ships have had to deal with large, massive rotating objects for decades. Counter-rotating props is the simple solution.


RE: Carbon Fiber?
By masher2 (blog) on 6/18/2008 10:39:09 PM , Rating: 2
> "So tension increases in proportion with rotational velocity (and energy), but actually decreases the more you increase the radius"

No, because linear velocity is dependent on radius. To better see this, look at the angular form of the centripetal acceleration equation a = w^2(r). Given constantly angular velocity, tension rises linearly with radius.

So, if we double the angular velocity, we quadruple the energy, but we also quadruple the tension. If we double the radius, we quadruple the energy, but we only double the tension.

Given that, one can best maximize energy by making a flywheel as large as possible for a given angular velocity, without exceeding the bursting strength of the materials.

However, this approach yields the largest moment of inertia, so for some applications (which the flywheel may be in motion) a smaller radius and faster angular velocity might be needed, to reduce precessional stresses on the bearings.

> "Just install two counter-rotating gyros. Their angular momentum cancels out, and you're left with just their mass"

Well, it's not quite so simple. In theory, the angular momentum of the combined system is zero...in practice, the two flywheels have to be *extremely* rigidly joined, as each individual gyro will generate extremely large precessional forces, which are only cancelled out if the coupling is strong (and rigid) enough to transmit them without breaking.

That coupling has to be through the bearings themselves...and making bearings strong enough to withstand precessional forces from turning a gyro holding enough energy to power a car, yet delicate enough to minimize frictional power losses, is very, very difficult.


RE: Carbon Fiber?
By energy1man on 6/18/2008 4:51:55 PM , Rating: 2
In case of catastrophic failure carbon fiber will disintegrate, a fly wheel made of say steel (or similiar material) would create a lot of high velocity projectiles you may not want to be around.


RE: Carbon Fiber?
By lco45 on 6/23/2008 5:46:33 AM , Rating: 2
It's more efficient to have the weight at the outside, near the rim. You need carbon fiber to be strong and light in the middle.
Luke


RE: Carbon Fiber?
By Jellodyne on 6/23/2008 10:13:42 AM , Rating: 2
Carbon fiber makes it go faster. The question you should be asking is why isn't it painted bright yelly, plastered with Toyo stickers and sporting a giant spoiler.


hurricane or portable power supply
By Screwballl on 6/18/2008 11:01:40 AM , Rating: 3
quote:
The company is packaging 10 of the flywheels together to give an impressive power output of 1 MW and energy storage capacity of 250 kilowatt hours. With the average household consuming approximately 8,900 kWh yearly, this would be enough to power a home for over 10 days.


Putting these in a portable unit can allow emergency facilities to have full AC power in the case of flood, hurricane, tornado or whatever other type of disaster hits. It would be nice to see this company mass manufacture these to give a neighborhood its power (as a backup in disaster prone areas) for a week when a hurricane takes out the power lines. I would be happy to turn off the 220V stuff around the house and have power for 3 weeks. Put one in my back yard! Hell I would switch it to this unit for 2 weeks at a time to be taken off the grid and pay the power company half of what I do.
Ivan knocked out our power for almost 3 weeks, Dennis for 12 days. Something like this could allow us to at least keep the ceiling fans going and some small 5000BTU AC units.




By phazers on 6/18/2008 11:36:44 AM , Rating: 3
Just don't buy any Sony-branded flywheel units. If you thought a laptop battery explosion & fire was bad, wait until you see what a bearing seizure or flywheel disintegration would do to your entire house :)


RE: hurricane or portable power supply
By nafhan on 6/18/2008 12:00:46 PM , Rating: 3
Just a guess, but it probably wouldn't be that great of an idea to move these while they are spinning. If you ever played with a gyroscope as a kid, you know what I'm talking about.
However if a disaster was imminent (hurricane, etc), you could move a few into place and then spin them up to provide electricity after the power goes out.


By Screwballl on 6/18/2008 1:08:32 PM , Rating: 2
agreed... theres ways around it of course... maybe some sort of large temporary generator to get them spinning and charged and only use the generator once a week long enough to charge them...


By radializer on 6/19/2008 11:04:36 AM , Rating: 2
On the same lines of though (imminent disaster coupled with the possibly lack of mobility when spun up), I wonder how robust the system is to mechanical shocks during standard operation?

Also, such flywheel systems should have significant levels of rotational inertia - so I wouldn't expect them to spin up to speed rapidly enough for an emergency response type of application. In fact, any one know what the spin-up time or "charging time" for such mechanical units may be?

As other have mentioned in previous threads, this does seem better suited to load-smoothing than any backup battery applications.


RE: hurricane or portable power supply
By PrinceGaz on 6/18/2008 10:47:15 PM , Rating: 2
Given that I'm on the Economy 7 electric-tariff in the UK, and am charged roughly 35% of the day-time rate for electricity used overnight between 0100-0800 hours, if a unit could like this could allow me to store up power overnight to be used during the day, I'd definitely consider it.

It wouldn't even have to store that much power, 7 KWh would be more than enough to see me through an average day of 17 hours day-rate, and then it could spin-up again overnight on the cheap electricity.

I suspect is is extremely expensive though, as storing large amounts of electric power has never been cheap (like reversible hydroelectric facilities which are probably the only real large-scale electric storage in use).


RE: hurricane or portable power supply
By masher2 (blog) on 6/19/2008 12:01:09 AM , Rating: 2
In addition to the cost of the unit itself, it appears that it's going to lose about 8% power per hour...or almost half after just 8 hours time. Plus, that energy's going to come out as heat, meaning you'd need an external building to store it all in, or you'd just be pumping all those kw-hours into the very building you're trying to air condition.

So this is really for short-term load balancing and phase correction by utilities...not long-term power storage.


By lco45 on 6/23/2008 5:49:51 AM , Rating: 2
You could also use a few car batteries for the scale you're talking about.

Luke


No More Brownouts
By pnyffeler on 6/18/2008 9:52:23 AM , Rating: 2
This should be a boon to California and other states where air conditioning is used heavily in the summer. The power companies could store up power at night for all of the peak demand times.

Solar power could also benefit from this tremendously.




RE: No More Brownouts
By Cheapshot on 6/18/2008 10:12:26 AM , Rating: 2
If it were connected to solar and wind or even water power sources this tech would soon be invaluable. Connected to current sources it makes sense only in the case of a power loss or brownout or the like.

I would like to know the efficiency of these mechanical batteries. How long will they store the megawatts... can they be sustained for a month, year, decade?


RE: No More Brownouts
By masher2 (blog) on 6/18/2008 10:23:44 AM , Rating: 2
> "How long will they store the megawatts... can they be sustained for a month, year, decade? "

If I read the spec sheet correctly, it loses 8% an hour at max load. The curve is probably logarithmic, though, so it could provide at least some power after a couple days.


RE: No More Brownouts
By Smartless on 6/18/2008 2:48:30 PM , Rating: 4
At that point you add the overweight hamsters.


RE: No More Brownouts
By bobsmith1492 on 6/30/2008 12:33:52 PM , Rating: 2
With their llama overseer


levitation
By reform on 6/18/2008 3:19:39 PM , Rating: 2
Could you reduce the friction of the bearings by having the flywheels sitting in a magnetic field that suspends the flywheels in the vacuum; ie like a maglev train?




RE: levitation
By Cheapshot on 6/18/2008 4:16:44 PM , Rating: 2
So it would rely on its own power to spin?


RE: levitation
By reform on 6/18/2008 5:13:54 PM , Rating: 2
I suppose using non-electro magnets to suspend the flywheels would be a little difficult given the weight of them! With a smaller scale flywheel, wouldn't it be possible to levitate and stabilise (ie repel from the chamber walls) the flywheels with normal high powered magnets, thus removing friction?
I'm no physicist, so I'd love to hear the reasons why this is unfeasable!


RE: levitation
By KaerfSusej on 6/18/2008 6:34:00 PM , Rating: 2
RE: levitation
By Myg on 6/19/2008 4:35:07 AM , Rating: 2
Laws change... Keep thinking/trying :-)


Price?
By WayneG on 6/18/2008 10:07:12 AM , Rating: 2
The idea behind this is brilliant, would save the hassle of a generator that's for sure. Only problem I foresee is pricing... I can see the usage for this product everywhere at the right price! A few solar panels and/or wind turbines and you'll be up even when noone else has power :).




By 2nd Abnormalized Form on 6/18/2008 2:38:52 PM , Rating: 2
Four tons, Mach 2, and a bearing failure. I'm sure they've made the containers strong enough, but that would make one heck of Bong! noise if the wheel cut loose.




Coming soon to F1 Racing
By AnnoyedGrunt on 6/19/2008 1:15:30 AM , Rating: 2
Formula one will permit flywheel power storage in the 2009 season. They are proposing a much smaller system of course.

http://www.motortrend.com/features/editorial/112_0...

-D'oh!




So let me get this straight
By FITCamaro on 6/18/08, Rating: -1
RE: So let me get this straight
By JasonMick (blog) on 6/18/2008 9:46:26 AM , Rating: 3
Sigh. No they don't output more power than is put in. They are not a perpetual motion machine; rather they output a large fraction of the stored energy, like a mechanical battery of sorts.

From the article...

quote:
Adding electricity spins the wheel faster. At any time this spin can be converted via a generator to power. Over time, the wheel slows, but this is a very gradual process.


RE: So let me get this straight
By djc208 on 6/18/2008 10:10:13 AM , Rating: 4
The total efficiency of the unit would be determined by the efficiency of the motor, the frictional losses of the bearings and rotors, and the efficiency of the generator.

The big two would be the motor and generator losses, friction should be minimal in comparison and can be reduced further by things like keeping the rotors in a vacuum (reduced air friction) and high efficiency bearings.


RE: So let me get this straight
By aBott on 6/18/2008 9:46:27 AM , Rating: 2
They're storing energy mechanically. Energy is put into the system by making the flywheel rotate. When power goes out, they can use all that rotational energy to produce electricity for a little while. In a way, it's kind of like a mechanical version of a capacitor.


RE: So let me get this straight
By masher2 (blog) on 6/18/2008 9:46:40 AM , Rating: 2
The system doesn't output more energy than is input; it's nothing but energy storage, essentially a large battery. When power is demanded, the wheels will slow down very quickly, but when it's not, the wheels can (I assume) spin for many days, very slowly losing energy from frictional losses.


RE: So let me get this straight
By RamarC on 6/18/2008 10:14:47 AM , Rating: 5
rotopaks have been around for decades and used the same concept but on a smaller scale. a company i worked for in the mid 80s had a 30kva rotopak that acted as a buffer between the power grid and the computers. the flywheel spun up off external power and ran a generator which produced power for the computers. surges and brownouts had virtually no effect on the flywheel and it could handle a 10 minute blackout at full load. once battery backup units came down in price, that was the end of rotopaks due to their size and weight.


RE: So let me get this straight
By Sulphademus on 6/18/2008 2:10:53 PM , Rating: 2
So its similar to regenerative braking on a hybrid car?


RE: So let me get this straight
By michal1980 on 6/18/2008 9:51:41 AM , Rating: 5
power plants use these already.

its an energy storage device.

put it this way, If the power company produces 10W of power.

9 might go out to the consumer, 1 will go to power up the flywheel... once the flywheel is maxed out. All 10W will go out to the cosumter.

Lets say something happens to the generator, and it losses power for a while. The fly wheel will then be coupled to its genertor to make up the power needed. So it will slow down and output Xwatts needed.

When the genertor comes back to life, it will replenish the fly wheel.

Now this can also be done at night. Say demand for power during the day is 11W, and at night 5W. You can still have a 10W genertor and a massive bank of flywheels. During the day the flywheels will generate the 1W of power. And at night, they will get power back from the main generator to be ready to go in the morning.

Think of a fly wheel as a mechinical battery.


RE: So let me get this straight
By amanojaku on 6/18/2008 10:00:48 AM , Rating: 1
I'd have to guess that this thing is useless unless it's paired to an energy source other than what is generated by the power company. Using electricity to generate electricity seems silly, unless the electrical source is solar power or something similar. Otherwise, the generators are forced to output more just to store it in these units. Maybe I need to reread the article?


RE: So let me get this straight
By mattclary on 6/18/2008 10:06:17 AM , Rating: 2
Think of it as a battery or a capacitor. You are storing energy to use later.


By masher2 (blog) on 6/18/2008 10:15:44 AM , Rating: 3
> "Otherwise, the generators are forced to output more just to store it in these units"

It does indeed sound pointless...until one realizes energy demand isn't constant, but rather fluctuates from (usually) a nightly low to a daytime high. With these units, a utility can "smooth out" sudden demand peaks without the need for a larger power plant.

Also, the units can be sited at substations, to provide temporary power in case of powerline or other problems.


RE: So let me get this straight
By epobirs on 6/18/2008 1:58:40 PM , Rating: 2
Not so. This can be highly useful in any situation where a standby generator is currently used. Hospitals, police, fire, and other emrgency services, data centers. Pretty much any place where continuing operations during a grid failure is worth the investment.


RE: So let me get this straight
By mrteddyears on 6/18/2008 10:07:23 AM , Rating: 4
Do they come with the hampsters or do you have to buy them on top ?


RE: So let me get this straight
By HVAC on 6/18/2008 11:11:12 AM , Rating: 5
The hamsters are included as a part of the complete system. Maintenance requires dumping feed and bedding material into a hopper not unlike the detergent and softener receptacles on the tops of front-loading clothes washers. Waste by-product is delivered to a removable bin on the bottom of the unit.

The genetically engineered "super-hamsters" that power the unit are guaranteed for the life of the product. Should one of the hamsters die due to a manufacturing defect or accident, the unit will emit a bad smell for several months. This emission in conjunction with reduced performance should give you plenty of opportunity to have the unit serviced by one of our highly trained repair professionals.

In emergencies the hamsters may be caused to output up to 125% of rated capacity by yelling at them through the feed inlet. This is considered hamster abuse and will void your warranty if performed. The company will consider elevated adrenaline levels in a failed hamster at time of service as evidence of such abusive action.

In no event should you taunt the hamsters or yell at them through the waste outlet. These methods have been found to actually decrease unit performance during the following moments as the hamsters void themselves in retaliation. Under the right circumstances it may even cause a waste outlet backup leading to eventual explosive clearing.


RE: So let me get this straight
By elessar1 on 6/18/2008 2:17:51 PM , Rating: 2
Also, you should keep cats and elephants away from "the unit", as hamsters may recognize them as a threat and direct a bolt of lightning of 1,2 Gigowatts at them!!!

greetings from SCL

elessar


RE: So let me get this straight
By elessar1 on 6/18/2008 2:17:52 PM , Rating: 2
Also, you should keep cats and elephants away from "the unit", as hamsters may recognize them as a threat and direct a bolt of lightning of 1,2 Gigowatts at them!!!

greetings from SCL

elessar


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