Velkess Energy Storage

[Ericp]

Next snake oil burner?

Or an old but viable system?

[Tony Bryer]

Not an unknown idea

[Andy Burns]

You can certainly build a flywheel UPS, but forcing suppliers of intermittent green energy to use one? That's a different matter.

[Dave Liquorice]

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.

[GB]

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.

[Andy Champ]

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

[Andrew Gabriel]

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.

[Tim Watts]

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...

[dennis]

Doesn't the big wheel store the energy equivalent of 50 sticks of dynamite? I'm not sure where I would want to put one of those other than in a big hole well out of the way.

[polygonum]

I am sure someone, somewhere invented a more sensible way of measuring energy. How many "sticks of dynamite-equivalent" does it take to boil one litre of water from 20C (assume no losses from kettle while heating up and boiling point is 100C).

I suppose electric companies might avoid standing charges if they billed in sticks of dynamite? Or would that be the other way around?

[newshound]

The thing about dynamite is that once detonated it lets all of its energy go at once. As does a flywheel, if it breaks.

Even in most faults (excepting vapour cloud explosions, which are not so easy to set up) the release of energy from a tank of petrol is relatively gentle in comparison. Similarly for a shorted lead acid battery.

[dennis]

IIRC a stick of dynamite is quite a useful measure as its about one megajoule.

[The Natural Philosopher]

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.

[newshound]

- I must remember that one. Not sure I will use it when writing nuclear power station safety cases, but it gives you an idea of what might be a safe distance!

[The Natural Philosopher]

I would disagree. I have seen batteries explode, and tankfuls of petrol

However your point is well made.

Having looked at energy storage extensively to discover whether here was any technology that could do it, as a way to even faintly justify renewable energy, I came to the conclusions that the safest energy store was in fact a few tonnes of plutonium, closely followed by a few million tonnes of coal.

heavy oil is next, then kerosene, with gasoline being very hazardous and gas alarmingly so.

water up a hill is fine, unless you get an earthquake, or mechanical faulure, in which case its is worse than a nuclear bomb.

What is truly alarming is the amount of energy we as a nation already store in hazardous form, and worse the amount we would NEED to store if renewable energy were all we had to work with.

I like to think of it in terms of 'Hiroshimas'

one 'Hiroshima' is about 160GWh. Or enough to supply the countries electrical needs for just 4 sunless windless winter days..

One Hiroshima 'could supply as much energy as 72 wind turbines for a year'

One Hiroshima a year 'could power up to 36,000 homes' (a very small town indeed)

as a nation we genearte and consume the equivalent of a Hirsohima every

5 days in terms of electricity. So 72 hirishiamn sizxed bangs are needed to power the grid.

Our total energy consumption is equivalent to a Hiroshima sized bang every day or so,

And that's just Britain.

[The Natural Philosopher]

safe distance from what?

nuclear power stations cant go bang.

[GB]

That's ridiculous! It depends entirely what is at the bottom of the hill, which you are ignoring. A nuclear bomb produces fall-out, which is bound to be harmful. A properly-sited pumped storage facility will flood a few fields, wash some crops away ....

[polygonum]

Interesting though that nuclear explosions tend to be in various multiples of ton(ne)s of TNT.

Does a failing flywheel really have a similar effective brisance to dynamite? I imagine individual lumps flying at high speed rather than the all round outward pulse as from dynamite (or nuclear) explosions. At a medium distance the dynamite will have run out of puff, whereas a piece of flywheel might have a much greater range - set against the greater possibility of it missing you entirely.

[Andy Champ]

Can you give more description?

I've never seen an accidental explosion of any size. I've heard of batteries catching fire, or boiling, but that's all. Tanks FULL of petrol tend to be quite safe - it's the ones full of petrol _vapour_ that go bang.

Andy

[polygonum]

Proper siting for the Möhne Reservoir is where it is for the geography/topology it required in order to be built. And damage to the dam itself caused somewhat more impact than a few soggy fields.