Using Flywheels to Meet Peak Power Grid Demands 325
hackertourist writes "A novel type of electricity storage was recently added to the New York power grid. The unit, supplied by Beacon Power, uses flywheels to store energy. This system is intended to replace gas turbines in supplying short-term peaks in power demand (also known as frequency regulation). It can supply up to 20 MW, using 200 flywheels."
If you can't afford a 200-flywheel system, you can always get a racetrack-ready Porsche 911 GT3 R Hybrid, which has a single energy-storage flywheel that can give you a 160 HP burst of power when you need a little extra oomph.
New tech? (Score:3)
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Re:New tech? (Score:5, Insightful)
In the case of these things, there seem to be many small ones (less risk if one "escapes") and something tells me that carbon fiber disks that are carefully stabilized and levitated in a vacuum while spinning incredibly fast...would break into a thousand pieces the second they left containment rather than rolling down the street and through someone's house.
Re:New tech? (Score:5, Funny)
..but there was a lot of NIMBY paranoia about flywheels breaking loose and roaming the countryside.
God, am I the only one who wants to live in a world where this actually happens and you see a bunch of ME's from the power plant with yellow hard hats on sprinting after it yelling "Shit-shit-shit-SHIT! -*crushes car* - SORRY! - shit-shit-shit-shit!"
Re:New tech? (Score:5, Interesting)
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Re:New tech? (Score:4, Interesting)
My worry isn't rolling stones, it's shrapnel. Beacon Power's flywheels store 25 kwh of electrical energy. If the rotor fails, this energy will be released in a fraction of a second, causing an explosion with the same energy as 20 kg of TNT. But TNT releases most of its energy in the form of heat, which is imperfectly converted to kinetic energy, while the flywheels will release pure kinetic energy. And it's kinetic energy that kills people. You'd better hope the engineer who designed the metal casing for the flywheel knew what he was doing!
Re:New tech? (Score:4, Interesting)
If memory serves, the giant flywheel that MIT uses to spark their fusion test reactor is rigged with explosive charges to blow it to pieces if it ever came loose. I believe the calculations show that without detonating it, it would likely continue *through* several buildings before landing in the Charles River... could have been an urban legend though.
Re:New tech? (Score:5, Informative)
Also in use in vehicles since the 50's.
http://en.wikipedia.org/wiki/Gyrobus [wikipedia.org]
Rather than carrying an internal combustion engine or batteries, or connecting to overhead powerlines, a gyrobus carries a large flywheel that is spun at up to 3,000 RPM by a "squirrel cage" motor. .... ... ...
Fully charged, a gyrobus could typically travel as far as 6km on a level route at speeds of up to 50 to 60 km/h,
Charging a flywheel took between 30 seconds and 3 minutes;
Sounds nicer than most electric cars.
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Ranges on EV these days are 30 to 300 km rather than 6.
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Yeah, I think I'll take a Lithium ion battery in my trunk before I take a 3 ton hunk of steel spinning at 900km/h. That's a lot of energy, and unlike a battery, that energy has to go somewhere if it breaks.
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That's very different. For instance one way that power fluctuations can be handled in an extremely complete manner is to use a motor-flywheel-generator set in direct connection as a power filter, with attendant losses in efficiency that you can imagine. IIRC at least one chip fab is/was protected in this fashion. This is about using flywheels like batteries.
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Add to windmills (Score:2)
I've always thought a flywheel like this at the base of each windmill would be an awesome way to level out wind power fluctuations.
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This is already standard practice. In fact, the entire fucking propeller acts a big flywheel. They are massive and balanced radially.
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novel? (Score:2)
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They where also used as a suppressor and UPS on mainframes. Some mainframes uses a big electric motor to turn a flywheel that was hooked to a generator to act as a voltage regulator. Very effective for brown outs and spikes. And yea I remember reading about them in PopSci in the 70s right down to the magnetic bearings, carbon fiber, and vacuum chamber. Also some pretty spectacular pictures of failures as well.
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Just a quick Note: You only need the id=___ and pg=___ (book Id & page number) parameters to link to Google books (usually just everything before the second & character.
http://books.google.com/books?id=kgEAAAAAMBAJ&pg=PA41 [google.com]
Also you can make a link like this [google.com] by doing this:
<a href="http://books.google.com/books?id=kgEAAAAAMBAJ&pg=PA41"> this </a>
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capacity (Score:2)
20 megawatts peak output? But how many megawatt hours?
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So, in monetary terms... (Score:3, Interesting)
... the system can buffer $500 worth of power (5 MWh = 5000 KWh, $0.10/KWh wholesale).
And it cost $40 million to build (at least that's the size of the loan)? That's 40,000 times the value of the energy it can hold.
If the buffering keeps an expensive peaking source off-line, it might pay for itself in a few years of continuous use.
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No, the technology that they are using requires maintenance power. These are only useful when attached to the grid and being used to ride out surges in demand.
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the article mentions ... 1 megawatt for as much as 15 minutes ... this is for each flywheel.
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You mean 100 kW for 15 minutes, per flywheel.
Gimbals (Score:4, Interesting)
Dumb question, I suppose. But, given that the earth rotates, and given that the flywheels will have a huge angular momentum, are they gimbaled? The article says they're suspended in a vacuum, levitated on a magnetic field, which is cool. But if they're not gimbaled a huge amount of energy will be wasted fighting precession as the earth rotates.
I assume the people making these things are smart and know their shit. I'm just curious how a problem like this is solved. If not gimbals, what?
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Oy Vey! - you orient the spin axis along true North.
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Nope. Then gravity torque gives you a mess.
They probably didn't mount them perfectly vertically. They probably also dynamically balanced them.
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But if they're not gimbaled a huge amount of energy will be wasted fighting precession as the earth rotates.
What means this "fighting precession?". As the axis of rotation changes there will be a torque on the axle -- big deal, this simply exchanges angular momentum with the earth. You just need an axle which can withstand that torque, and it ain't much torque.
Re:Gimbals (Score:4, Interesting)
But if they're not gimbaled a huge amount of energy will be wasted fighting precession as the earth rotates.
You don't need to gimbal them. If oriented correctly you can draw energy from the rotation of the earth to fight the precession effects. Basically nearly all of the force that keeps the axis aligned is transmitted through the mounting, and only tiny amounts will be derived from the rotation. Induced currents will be a more significant source of losses.
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Re:Gimbals (Score:4, Informative)
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Re:Gimbals (Score:4, Insightful)
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Dumber question: if one imagines a vast number of these flywheels buffering intermittent energy sources such as wind and solar at enough scale to power the US, will the flywheels slow the rotation of the Earth significantly?
... or speed it up depending on the direction of spin? Alternating directions in different units (turn every other unit upside-down?!) should combat this effect.
Alternatives (Score:3)
Does an obese cat in a giant hamster wheel count as a flywheel? No? What if I just hooked up a DC generator to it and dangled some liver on a stick? How many Watts could I get?
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Does an obese cat in a giant hamster wheel count as a flywheel? No? What if I just hooked up a DC generator to it and dangled some liver on a stick? How many Watts could I get?
In my experience, 2.21 jigga-watts (depending on the viciousness of the large dog behind the cat).
After reaching an angular velocity of 88mph, you can send the device back in time to double your energy output -- The process yields unlimited Infinite energy (well, except for the limits of the world's production of meow-mix and cat-litter).
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Does an obese cat in a giant hamster wheel count as a flywheel? No? What if I just hooked up a DC generator to it and dangled some liver on a stick? How many Watts could I get?
One horsepower is about the average sustained power output of a horse (imagine that!). There are always substantial energy conversion losses, and a fat cat is non-optimal compared to a born and bred working horse, so I feel comfortable saying you'll get about 500 watts per horsepower.
Long term power output probably scales as weight, short term probably as surface area. A fat cat probably weighs more than 10 pounds and a hard core work horse probably weighs more than 1000 pounds. So I feel confident that
What's the cost? (Score:5, Interesting)
Why don't these alternative energy/power storage articles ever include cost comparisons? What do these flywheels cost to buy and operate compared to what they're replacing?
Re:What's the cost? (Score:5, Insightful)
They compete with batteries. They are more expensive than crappy dirty ones and cheaper than fancy relatively clean ones. They are made with steel containment vessels and contain a bunch of electromagnets which you and I know as being made of wire. You can check pricing of maglev bearings online. The flywheels are made of carbon fiber so that if they should for some reason contact the housing, which as I recall is about an inch thick steel unit, they shred themselves into cotton candy or confetti or something like that instead of releasing their energy explosively. The various materials they're made of means you can assume they have a fairly high energy cost of production. The units are small enough to be ganged in shipping containers.
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Kinetic energy is 1/2 m * v ^2.
Increased mass will only increase energy lineary, but the squared velocity term means that if you double the speeds you get four times the energy.
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Well, these are energy storage units rather than energy generation units. The electricity is generated elsewhere by cheap baseload generators and these flywheel units store it until it's needed to makeup shortfall by peak load. This gives you enough time to spool up the slow-reacting baseload generators.
What they're replacing is probably gas turbines, which are expensive to run but have a very short reaction time and are generally used to meet peak loads. And gas turbines are generation units, so you can'
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Not quite TFA, but here's a report from KEMA [beaconpower.com] (pdf).
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There will be infrastructure costs associated with building them but there is no 'fuel' or significant ongoing cost. At least no more so than a comparable power generation plant. So that washes in terms of cost.
By using renewable sources, like solar or wind, there also is no 'fuel' involved at all. This allows that intermittent renewable source to provide power when the source isn't producing directly.
Re:What's the cost? (Score:4, Interesting)
but they don't see that the CO2 output of building the damn thing divided by its useful lifetime is much higher than a heavy polluter coal plant that lasts much longer and is easy as hell to build.
It's not. Please let us know why you think it is.
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It depends on what system you're looking at. Old solar panel technology took a large amount of nasty chemical pollutants to make, and produced a hell of a lot of liquid toxic waste output. I think our solution has been to dump it in the water supply... newer processes are cleaner, though.
It's like buying a fleet of electric or hybrid cars for their "environmental impact," while Toyota won't release statistics on how much energy goes into building one and how much pollution it produces. There's no total
Re:What's the cost? (Score:4, Interesting)
It depends on what system you're looking at. Old solar panel technology took a large amount of nasty chemical pollutants to make, and produced a hell of a lot of liquid toxic waste output. I think our solution has been to dump it in the water supply.
That has nothing to do with co2. All commercially available solar panels have had payback times in co2 terms of less than 50% of their lifetimes.
It's like buying a fleet of electric or hybrid cars for their "environmental impact," while Toyota won't release statistics on how much energy goes into building one and how much pollution it produces. There's no total lifetime numbers for something as innocuous as CO2, which leads many to speculate that Toyota might keep such things secret because the total CO2 production for an electric hybrid exceeds the total CO2 production for a 25mpg Sedan over its expected lifetime. Less not knowing, and more not caring because the numbers in front of you support your foregone conclusions already.
You can figure out how much energy goes into making one, look at the price. A 25mpg sedan is going to probably cost more than a prius anyway, as it only gets 25mpg for a good reason. That is because it is heavy and made from more material generating more CO2 when it was produced.
A corolla might be better over the lifetime of the car in co2 terms vs a prius, but that 25mpg sedan won't. An electric car in fleet use might be even better, depends on source of that power.
Your talking points suck. Stop moving the goalposts and do some fucking math.
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Your talking points suck. Stop moving the goalposts and do some fucking math.
Ahh of all my math classes at university, that was my favorite.
The problem is, the math is unclear.
For example, my wife's prius cost about 20K and I pay about 8 cents/KWh because I live in a civilized part of the country, so if every penny of the cost went to energy in its most polluting form, fossil fuel electricity, that would be about 250 megawatt-hr... at 2 pounds of CO2 per KWh at a fossil fuel plant, thats about half a million pounds of CO2 per "car cost equivalent of electricity". For the money I ga
Re:What's the cost? (Score:4, Interesting)
Looking at the price for CO2 cost is a lot more accurate than some might think. There's some research which shows that costs closely track energy used in production, and that in turn should closely track CO2.
Sure, some things deviate, like the priciest wine vs the cheapest, but for things like pens, cars, computers, where pricing pressure exists (even for most luxury cars!) it seems to mostly hold.
Very cool, but very not new (Score:3)
About a decade ago these guys had or at least were advertising a tiny version of this technology for use as a UPS. It was supposed to be cost-competitive with medium-size units. Unfortunately it turns out that there's more profit in solving the peak demand problem by absorbing base load at night and delivering it during peak demand periods. Since they use maglev bearings, [partially] evacuated chambers, and magnetic induction, the units themselves are not only very efficient but should also have excellent longevity. It looks to me like they are making the chambers out of fairly standard (if sizable) pipe components.
New flywheel design (Score:3)
Jeff Veltri of Temporal Power has a flywheel design he claims can deliver twice the power at half the cost of the Beacon designs. Ten of his prototypes will be used for smoothing wind turbine power production. But his design is based on permanent magnets so I wonder how that'll fare which the rising cost of rare earth minerals.
http://www.thestar.com/business/article/978578--hamilton-a-new-spin-on-energy-storage [thestar.com]
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But his design is based on permanent magnets so I wonder how that'll fare which the rising cost of rare earth minerals.
It seems like if you are capable of controlling the entire design you can use pretty big magnets, so you can therefore use cheap ones.
Slashdot - yesterday's articles are today's news (Score:2)
taking stock (Score:2)
Power should cost more during day time. (Score:4, Insightful)
Re:Power should cost more during day time. (Score:4, Interesting)
Domestic electricity prices are constant all day.
Maybe where you live, but not where I live. I bet if you requested the time based pricing you could get it. When I was growing up we only did laundry and dishes after 8pm. Cut the electric bill by a huge amount.
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I don't know where you live, but we've had double meters (night and day) for as long as I can remember.
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Wrong - many areas charge residents more during peak periods. California is especially known for this, and it's one of the reasons (lots of sun being the other) why residential solar power is fairly popular there. Peak solar generation times happen to coincide with peak electricity cost times.
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Heck, why artificially set prices at all? Someday everyone will be recharging their electric cars at night and companies will beg us to use electricity during the day instead.
Now that meters are getting high-tech enough, we should just have a spot market for power and buy/sell into that market any time of the day or night.
15 mega watts of energy storage (Score:2)
Seriously why use stupid units in these stories. The system provides 15 mega watts for 15 minuits. Thats 3.75 Mw-h. according to the wikipedia an average person uses 11,400 W (average not peak).
So this can power 40 people for 8 hours.
Now you'll have to excuse me I have a meeting in 2.8 hogsheads. After that I have to goto the store and buy a meter of milk. And my furnace is a 15000BTU model and it's used them all up.
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Sure, not mentioning its storage capacity is an omission, but quoting the maximum power output is hardly irrelevant or stupid.
Re:15 mega watts of energy storage (Score:4, Informative)
That average energy consumption isn't just electricity. Average electricity per person is just 1460 W for the US, which is what this system is for.
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You've got a 3-gill head in a 10-bludger hat.
This thing isn't meant to supplant the entire supply in case of a blackout. It's meant to give the grid a few MW for a few minutes to prevent a brownout that could cause a blackout.
And it's probably not meant for a major portion of the grid, just a locale with an incipient supply problem.
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Liebert tried this. (Score:2)
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maglevs aren't loss-free. eddy currents in the conductive elements. you'd have to get it to superconduct as well. then you might have perpetual motion, or as close to it as quantum losses will allow.
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Re: a flywheel's rotational momentium
That's an interesting point.... so the engineering solution is to upend the flywheel like a Farris wheel and angle it in the direction of the earth's rotation. But I wonder how much of an effect this would really have if you kept the flywheel planer to the earth's surface? This seems like a complicated but simple question at the same time. The desire for the flywheel to maintain it's angular momentum would lead to more force (and therefore friction) on the rotation ba
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The protons are an important component of the matter that the flywheel and the magnets are made of....
I'd assume that the electrons aren't involved much until the (matter making up the) flywheel starts rotating through a magnetic field, thus converting the kinetic motion back into an electrical current.... ?
Re:and if you use maglev bearings (Score:5, Informative)
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As described by robthebloke - It's a component in some KERS systems but not all.
The basics of KERS are known in the general auto industry as regenerative braking. It's a fairly common thing and is one of the largest benefits of hybrid vehicles. It's why hybrid vehicles are often matched in highway mileage by some traditional vehicles, but they crush traditional vehicles in city mileage (primarily because they don't take that mileage hit from stop-and-go driving, which wastes a lot of energy heating the br
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In much the same way that putting a one-pound weight in your car reduces its fuel economy.
Re:and if you use maglev bearings (Score:5, Informative)
The Coriolis effect is far too small to have any significant impact on flywheels this small, it only really has an effect on large scale systems such as cyclonic storms and even then it's amplified due to the proximity to the equator.
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The smaller you make the mechanical losses in the system, the larger the relative contribution of coriolis effects becomes.
But since coriolis effects are static for a given angular momentum, latitude, and attitude, the force on the bearing would be constant so as long as the bearing surfaces are out of contact you're good.
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The discs do appear to be parallel to the ground so keep in mind that depending on which way they are spinning and which hemisphere they are in, the Coriolis effect will either help or hurt them.
Uhhhg. Depending on the direction of the disks' spin they are slowing or speeding our planet's rotation!
I feel obligated to link you here. [xkcd.com]
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The Coriolis effect doesn't affect the energy stored in a closed system, right?
:-) but a serious question, what % loss? (Score:3)
haha, +1 for funny posting :-)
But a serious question for anybody who can help - we know that there's no perfect energy retaining system, there will always be losss through friction etc, what sort of loss might you expect with these fly wheels? Do they return 50%, 80%, other amount back to the grid?
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I would bet that losses in the transmission system are bigger than losses in the flywheels, and the more you need the flywheels the less that is.
Re::-) but a serious question, what % loss? (Score:5, Interesting)
The efficiency of an electric motor can be in excess of 90%. Energy is transferred to a flywheel via electric motor, and extracted (mostly likely) through the same electric motor, so your maximum theoretical efficiency is going to be your motor efficiency squared. If they tried hard, probably something like (92%)^2 or something like 85% total storage efficiency.
This is of course assuming that mechanical losses are zero, but given the design they are very likely to be close to perfect. There will also of course be some energy lost indirectly in levitation/cooling/ohmic stuff outside of the flywheel.
I think the thing about this article that bugs me the most is they say that the flywheels can store 20MW. What on earth kind of way to measure an energy storage device is that? 20MW for 0.5 seconds? 20MW for three days? Embarrassing.
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we know that there's no perfect energy retaining system
Actually, we know you are ignorant of superconducting solenoids.
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The assembly would also need to be made non-conductive, otherwise I presume that the presence of Earth's magnetic field will slowly brake it due to eddy currents.
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Look up pumped storage hydroelectric power: http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity [wikipedia.org]
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Problem with that is that it requires epic amounts of water and geography that cooperates to store that water at a sufficient height.
You need about 367,000 litre-metres (367,000 litres of water raised 1 metre, or any equivalent product) to store 1 kilowatt-hour, and that's not accounting for losses either.
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Basement flywheels have been considered for solar or wind energy storage, but as with any energy storage, if the energy is released suddenly in a small volume, you've got a bomb on your hands. You certainly wouldn't want to skimp on maintenance for such a device.
Flywheels used to be used for energy storage on farms before electrification. Often for pumping ground water. The classic farm windmill would be hooked to a gas motor with a flywheel and a pump. The motor had a governor to cut the fuel/air inta
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Might take awhile to pay itself off. Discover ran an article [discovermagazine.com] that priced a unit at $800 for one small flywheel.
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like small nuclear bombs
25 kWh = 0.000021511 kT = 0.021511 T = 43 lbs of dynamite.
Not insignificant on a human scale, but pretty lame as nukes, or even conventional air-dropped bombs, go.
If it could release all the energy at once, in all directions, it'd probably make a mess of your house, if it were just sitting exposed in the living room. But, since the rotating part is well under ground level, the casing is evacuated, and the flywheel is made of the sort of impact-dissipating stuff car makers use to meet crash-safety requireme
Re:NaS batteries beat flywheels hands down. (Score:4, Informative)
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 [beaconpower.com] from the manufacturer.
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Flywheels have high power density by volume, weight and cost. Good for filling deep, short power gaps. Batteries have better energy density by volume, weight and cost. think of a flywheel as somewhere in between a battery and a capacitor.