Velkess Energy Storage

Next snake oil burner?
Or an old but viable system?
http://www.kickstarter.com/projects/1340066560/velkess-energy-storage
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On Mon, 15 Apr 2013 03:01:26 +0100 Ericp wrote :

Not an unknown idea
http://en.wikipedia.org/wiki/Flywheel_energy_storage
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Melbourne, Australia www.greentram.com
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Ericp wrote:

You can certainly build a flywheel UPS, but forcing suppliers of intermittent green energy to use one? That's a different matter.
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On Mon, 15 Apr 2013 08:25:48 +0100, Andy Burns wrote:

Simples, you change the rules, after all if Germany can just switch off all their nuke generation overnight by changing the rules...
"If you want to connect and sell power to the grid you must have your rated capacity available within the time scale and for the minimum duration as laid out in Appendix X".
Appedix X then gives various time scales for various generation technologies, so lets say 4 days for coal from cold. 6hrs for CCGT from cold, 1 hr for wind. Duration being at least 12 hours.
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Dave.
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On 15/04/2013 03:01, Ericp wrote:

A number of claims are made in the video, eg half the cost of equivalent lead acid systems, but there is nothing to back this up.
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On 15/04/2013 03:01, Ericp wrote:

The prototype weighs 25lb and stores 0.5kWh.
A car battery weighs about that, and stores maybe 100aH, at 12V that's 1.2kWh - so the energy density is similar to, but less than, a lead-acid battery.
It looks as though they are having trouble scaling it to a 750lb rotor which will store 15kWh. That would run my house for a day and a half. I need to cover a week's calm spell so I can run on windmill power alone - so I need 5 of these things in my basement.
Snake oil.
Andy
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They have been used in the computer industry to provide the tie-over between mains fail and generators starting up, for large uninterruptabe supplies.
They do have some quite spectacular failure modes. I suspect that's partly why they died out.
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Andrew Gabriel
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On 15/04/13 09:20, Andrew Gabriel wrote:

I remember distinctly being given a 'lift' from Farnborough to IIRC Gatwick as a guest on Deccaqs 'Elizabethan' (converted from the Shah of Persias private transport to a radar test rig,(but the mahogany and gold plate was still in evidence) and hearing the whine of the rotary converters...'whats that?' 'rorarty converters for the equipment' 'why not use a transistor inverter' 'cos when we drop the flaps or pull the gear up, the voltage drops to half: the rotaries have enough energy to keep the valves lit for half a minute'
Inertia is better than a capacitor, not as good as a battery except for short duration stuff, and its extremely hazardous when you push near the limits from more energy storage.
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On Mon, 15 Apr 2013 08:20:48 +0000 (UTC), snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote:

The GPO installed them in 1960s & 70s telephone exchanges. The rotor was installed underground.
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On Monday 15 April 2013 09:14 Andy Champ wrote in uk.d-i-y:

Wait until the first one throws its bearings and takes out 3 houses...
Then there'll be "Part R" "Approved Document for Installation and Maintenance of Fuckoff Large Spinning Machines" and 6 registered bodies to represent the installers...
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On 15/04/2013 09:14, Andy Champ wrote:

Do they mention the self-discharge rate? I'd expect it to have run out,( if built as shown on the page) of energy within a few minutes at the most due to air friction and other losses, as against a lead acid battery, which takes months to flatten itself. It may come in handy for absorbing motor start surges, if you can afford to have it running "just in case".
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On 15/04/2013 14:49, John Williamson wrote:

Did you miss the bit about the enclosure being evacuated?
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Rod

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On 15/04/2013 14:51, polygonum wrote:

Obviously, though it'll still probably be flat within a day or so. Was it in the video? I'm away from home at the moment, and I can't afford video on 3G in this country.
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On Mon, 15 Apr 2013 09:14:32 +0100, Andy Champ wrote:

One thing I haven't seen mentioned so far.
Will it deliver the 15kWh at a consistent rate?
Not my field, but I do wonder if it can deliver a lot of power when it is spinning really fast but the output may reduce as the flywheel slows.
I presume the technology exists to smooth the generated output to give a constantly variable output at all speeds of rotation.
I also assume that they will have to be pretty damn big as well as heavy to store a useful amount of energy.
Possibly fine for countries/areas with a low population density but I don't see these as an easy fit for any UK urban or suburban location.
I assume they would need to be buried to avoid damage on bearing failure being widespread.
Cheers
Dave R
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On 16/04/13 12:54, David.WE.Roberts wrote:

Your assumptions are well founded.
Yes to all the above.
Its nothing new. There IS nothing new in storage. Its all years old ideas that are being dressed up in Green emperors new clothes because
- the assumption that renewable energy HAS to be made to work is driving the possibility of getting massive subsidies and - people without engineering backgrounds will believe anything and are easily parted from their money.
The ENGINEERING reality is that far far better stores of energy exist ready made in the form of fossil fuel and fissionable and fertile materials.
There is no need to create it with an expensive inefficient and physically massive and expensive transient technology and then store it in another expensive inefficient and physically massive and expensive (and potentially highly dangerous) technology in order to do the same job.
the energy density of atomic binding energy is at least three orders of magnitude above anything else we know of, and can use. That means storage is small and has little impact on other things. The fact that its extraordinarily difficult to access it at all, makes it somewhat expensive, to access, but inherently very safe. And as far as our curent thunking goes, its te primary energy driving the Universe. It doesn't get better than that.
The excess of radiation generated by nuclear power is less than one percent of the total radiation we receive. It really is a non-issue.
Eventually these facts will be recognised, but sadly it seems, not until every other alternative has been explored, because people like to believe, rather than learn science, do sums, and face reality.
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Ineptocracy

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wrote:

id

I
-

is

a
y
e
t
.
Still got your head up your arse. My cat knows more science than you. You think constant repetition creates facts.
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On 16/04/13 16:19, harry wrote:

No harry, I think the world consists of facts, and not opinions, but the facts need advocates.
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Ineptocracy

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On 16/04/2013 12:54, David.WE.Roberts wrote:

It could be done, but there are cheaper more reliable ways using batteries and inverters these days. I can't recall the spec of the largest one to date but it was in the 10-20kWh range in the 1970's.
It is a very old mechanical UPS design. Whilst there is good mains power a clutch keeps the drive from mains to generator in - lose mains and the flywheel keeps the generators going until it runs out with gradually falling frequency so you have to hope the load is tolerant.

Such things have already been successfully engineered. The I know of was the emergency shutdown flywheel supply for the MRAO Ryle 5km aperture synthesis telescope at Cambridge where the stored kinetic energy in the flywheel was intended to stow the instruments back to vertical in the event of mains power loss in a storm.
Big dish scopes have been wrecked in storms through losing power and emergency generators failing to start. ISTR alignment of the bearing was carefully chosen so that if the rotor broke loose it would not hit anything in the two miles or so it was expected to travel.
The main problem with this method is that to be any good at energy density the flywheel necessarily contains a very dangerous amount of kinetic energy. Think robot wars Hypno-Disk on steroids.
http://en.wikipedia.org/wiki/Hypno-Disc
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Martin Brown
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Martin Brown wrote:

Use a DC motor/generator and use an inverter. It increases the cost, but makes the system much less critical of rotor speed. You need more than 3000rpm at the flywheel to get a decent energy density per unit mass, too, so you need to add gearing to keep the output frequency right on a synchronous system, which causes its own losses.
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On 16/04/13 15:27, John Williamson wrote:

exactly so. Inverters exist that are capable of working over at least a 3:1 input voltage range. You will get constant output followed by totalshutdown, rather than a steadily falling one.
Of course everything is now bigger, heavier more expensiveand more useless than ever...
But that's renewable energy for you...
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