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Beacon Power tried to commercialize that concept 5-10 years ago. Their flywheels were cylinders of spun carbon fiber, in vacuum chambers, and levitated on magnetic bearings. These were sunk into concrete silos - in case any one of them flew apart. The technology was used not so much for bulk storage, but rather for peak-shaving and arbitrage.

The company went bankrupt a couple of years ago after building their first 20 MW storage plant. They're now owned by a private equity firm and making another go of it, so there's hope yet.

http://beaconpower.com/

The energy stored in a flywheel is I * omega ^ 2. With the materials we have available now and the size you want to allocate to such a thing, manufacturers have found it works best to have a flywheel with a modest moment of inertia and crank the rotational rate way up high (100,000 rpm for starters). To keep the flywheel from spontaneously shattering, high speed flywheels are mostly made from carbon fiber. And with the flywheel spinning so fast, the only way to keep them from losing energy to friction is to have them spin in a vacuum on magnetic bearings. Then you add in a high efficiency motor/generator, with some serious power electronics to commute the phases at ~kW power levels. These are all proven technologies (see Beacon Power), but compared to a bank of lead acid batteries, it isn't an affordable solution for a home.

No, TFA is confusing statistics of individual flywheels with clusters of them. The individual 25 kwh flywheels are grouped into modular clusters of 10: each of these 10-unit modules delivers 250 kwh (1 MW for 15 mins), and is the size of a couple of cargo containers. See this white paper from the manufacturer.

Not quite TFA, but here's a report from KEMA (pdf).

I think the charge stations will have some local storage of electricity, be it super-capacitors or flywheel based systems like http://www.beaconpower.com/ and those charge stations in the morning will be starting slowly charging their energy storage and even having a sign of how much energy they have (can they quickly charge only a light car or a truck) similar to battery sign on mobile phones or notebooks, the same size current gas stations show prices. And when you see that some charge station is full you go and charge there, if it's empty you go to the next station.

It's a volume/weight/expense thing. At a stationary installation the first two do not matter.

You could have a bank of these but a flywheel or flow battery would likely be cheaper at this moment in time.

The issue is more with the flywheels or other storage systems...they don't exist. The stuff made by Beacon Power is still pretty low energy density. Their main product seems to be a 25kWh flywheel which a 3MW turbine (like a Vestas V90) could fill to capacity in minutes. Take a look at their frequency regulation plant. It's a pretty cool concept but it requires a pretty big plot of land compared to the total power it stores up (also...people are scared of flysheels, something about 90MJ of power escaping and rolling around the countryside).

I'm optimistic about it, but the storage is not there yet (but the wind power is)

Well i work nearby an ISP and they have a few of them. The problem is their expensive, while their energy storage is quickly drained or lets say limited. In case of the ISP, they use them just to prevent a powerdip if the grid goes down, so they have time to start diesel engines for power generation. Anyway take a look at this plant below it is a flywheel plant. http://www.beaconpower.com/products/EnergyStorageSystems/SmartEnergyMatrix.htm

Altough that plant can hanlde peak power fluctuations, it can not handle long perios delivery of energy. The earlier peak powerplant can handle 20 ~40 megawatt.. while a tipical big windmill allready delivers about 2 to 10 megawatt.

.. maybe dough its possible to store the energy inside compressed air ..

Pump an bunch of water, what could possibly go wrong? That might have worked in the middle ages but solar power demands efficient storage. There isn't enough to go around as it is, and you want to burn it moving tons of water? What about the pump's efficiency? What about the friction in the pipes? In the words of Samir Naehninejhad: Tom, this idea, this is horrible.

Surely a frictionless flywheel is the most efficient, currently (no pun intended) viable solution. A number of vendors, such as Beacon Energy have products in service already. No chemicals, no research, no haz-mat crew. Plus if they apply a light vacuum, the efficiency increases! With the new carbon composites they will have these rotating at 100,000rpm+ in the near future, and we will be able to easily and renewably store energy during dark hours.

The most important thing is that we need to CUT BACK on our nighttime power use. The easiest thing would be to simply change the workday for all government employees to sunrise-sunset. It works naturally, because that's when people want to work. And in the winter, people can sleep more, like we were meant to (which lowers heating costs because you're in PJ's and under the covers, and [if you ever get off Slashdot], perhaps snuggling with a Lady). Since most other industries depend on government services to some degree (from post office to the city planning department), they would evenutally fall in sync.

And of course, cutting back in general would be even better. Most of our energy use is cars. So, provide tax incentives to people who live close enough to walk (1 mile) or bike (3 miles) to work each day. Even if you don't walk or bike, you still get the tax incentive if you just choose to live close to work because you are saving lots of gas that way. I predict an even more massive rise in Downtown real estate prices in every city because of this. Not only that, less car-miles means less accidents, and lower insurance payouts. It also means less wear on the roads, meaning less tax expense, so we could spend the same money on something else, like education. People will buy fewer cars, which means less energy is required to produce and ship steel. WHAT ABOUT THE JOBS?! Well, for one thing, we're going to lower the work week 1 hour per day to 35 hours a week. What will you do with all that spare time? WALK!

There are indeed losses, but much less than you propose. Most solar DC to AC inverters are 90-93% efficient in their conversions - so only a 7-10% loss. http://www.beaconpower.com/products/SolarInverterSystems/docs/M4_M5_plus_datasheet_web.pdf The same goes for the conversion back to DC on the equipment side.

Who modded this down? This is a genuine aid to small short-term variations. See beacon power. I am not sure that such technologies could cope with day/night fluctuations though, for these long period variations probably pump storage hydroelectric may be better. They are probably complementary technologies, as it takes a pump-storage plant about a minute to reach full load from stand-still, or 15 seconds from "hot standby", where the turbines are kept spinning under zero load.

I love the grid backup idea. http://www.beaconpower.com/products/EnergyStorageSystems/SmartEnergyMatrix.htm
Although you could probably tow one of these behind a GE Hybrid Locomotive pretty well. In Portland they have an old tain line where an electic trian pulls a generator, why not pull a flywheel?

theres much better tech comming out to just this... power load balancing.

beacon power company

basically they have large arrays of flywheels that will spin up to store electricity say at night when demand is lower. and spin down to give it back out during the day when the demand goes up.

they just got approval and all that for installing a large array somewhere in the US.

http://www.beaconpower.com/

And. it doesnt add a bunch of crap to our cars.

Wikipedia:
http://en.wikipedia.org/wiki/Flywheel_energy_storage

Example of current utility flywheel manufacturer:
http://www.beaconpower.com/products/EnergyStorageSystems/SmartEnergyMatrix.htm

High end computer UPS systems utilitize a mechanical bearing flywheel in addition to batteries.

Here are three home power flywheel companies:
http://www.motionnet.com/cgi-bin/search.exe?a=cat&no=2229

Flywheel batteries at the substation, and even at the house.
This way the whole grid could be backed up for a short time. Also don't for get the effiecy can be increased by using mirror array
to focus more light on the cell. Ahh the combination of solutions.

There's a company called Beacon Power that has something called the Smart Energy Matrix, which is basically a standard container with a bunch of flywheel energy storage units in it. According to the brochure, it can supply 250kWh @ 1MW load. You could use this thing to store the energy to run the system in an emergency. Obviously you have to charge it up with something, but I thought it might be of interest.

There's a company called Beacon Power that has something called the Smart Energy Matrix, which is basically a standard container with a bunch of flywheel energy storage units in it. According to the brochure, it can supply 250kWh @ 1MW load. You could use this thing to store the energy to run the system in an emergency. Obviously you have to charge it up with something, but I thought it might be of interest.

slashdot is supposed to be for geeks: i would like to see a DIY flywheel backup system; efficiency is on the order of 95-98% if you use magnetic bearings... there is an exellent IEEE article in the IEEE spectrum magazine a while back -- it's not online though; few links here: Flywheel energy storage Magnetic Bearing stuff

Reminds me of those old MFM Seagates...

Seriously - does anyone really want something that weighs half a ton and spins so damned fast that it'll drive a generator for three hours sitting next to them?

We're going back to moving parts here. At least a battery-based UPS would have minimal moving parts, probably a few relays for overcurrent protection and a transformer with a moving center tap to regulate voltage in the traditional UPS. With a big moving part like a flywheel, we have got a fair bit of noise here. The specs say less than 55 dB, which is roughly the amount of noise produced by a typical conversation. And the efficiency of the system is somewhat pathetic. The system can store up to 2 kWh of energy. It takes three hours for it to store up this much energy with an input power of 2.5 kW, meaning you input 7.5 kWh of energy to it. The remaining 5.5 kWh of energy was wasted. Wasting so much energy is not the way to be environmentally friendly! True, a traditional battery based UPS would cause environmental pollution when you tried to dispose of it, but 5.5 kWh of wasted energy every time you had to recharge the thing would likely produce even more pollution in total. True, the system may have many potential advantages, especially for use in harsh environments that would ruin most battery-based systems, but to call it environmentally friendly is an absolutely laughable claim. It is probably even less environmentally friendly than the average battery UPS, it just produces a different kind of pollution (by wasting much of the energy provided to it from the power generation system). And one more thing: the thing is immense, it weighs a total of 1050 lbs!

The company took great pains to discuss flywheel safety. As you know, there is a pretty big danger of this massive disk spinning around at high speeds and suddenly breaking apart due to physical forces and spreading shrapnel around everywhere.

I think it is bound to happen as these devices become more popular, but it probably will be fairly unusual.

The only reason I mention this is that I am "somewhat" amused by the idea that a new technology is creating a new way of dying as well. Perhaps there will be a day where the casual newspaper reader will come across the headline "Two engineers killed in flywheel discharge in Coeur d'Alene" and not think it out of the ordinary.

This also goes along with the idea that mother nature will invent all sorta of gruesome ways of dying to deal with the fact that we keep on solving conventional ways of dying as time goes on. In the end, I suspect that she will be forced to rely on spontaneous human combustion as the catch-all unsolvable/incurable death once science has cured disease and engineers have prevented most accidents. Until then, expect that flywheel discharge will occasionally send a hapless individual into their next life.

From their technical specifications page . . .

Weight--Flywheel Module: 850 lbs
Weight--Electronics Module: 200 lbs

That's a total of 1050 pounds! I'll stick with my 5 pound APC UPS for now. Plus, my landlord would not appreciate 1/2 ton of weight in our second floor computer room!

The specs on the flywheel system are pretty interesting, too. It is definitely big and noisy - more so than my 586 full tower web server box.

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the primary problem is that there is no efficient way for power providers to 'store up' on power. they can't run a plant just as hard at night, and save up electricity to meet the peek demand - they have to generate at near the level of demand or lose it.(at least alot of it)

as soon as someone wakes up and realizes that battery backups are about the worst way to store energy, maybe we can start to deal with it.

back a while in wired (8.05) there was an article about using flywheels to store energy (story). and a former aeronautics guy (company) who was working on it. (there's also some others link, link, and probably others) it was truly fascinating and they claimed energy storage efficiency of many times the level of currently used batteries. (not much of a feat, batteries suck)

Nasa's power and propulsion office was looking to replace the batteries in the ISS with this stuff (story) what ever happened to that crap? and how long will it take power companies to catch on?

perhaps only the lack of competition allows them to point figers instead of solving their problems?