Velkess Energy Storage

You really don't want to be around when a spinny thing loses its bearings...

Oh they can, as can any high pressure hot water/steam plant. You lose the pressure and it will rapidly turn to gas and go bang.

If you are a regular watcher of mythbusters and similar programmes, you will will be aware that explosive power alone is not what kills people. Yes at close range you may get literally blown apart, but the far greater damage is shrapnel. with which military explosives are deliberately augmented. A rifle is a carefully designed shrapnel generator, with a kill range of up to several MILES. For very low energy. Ther ws one case in te USA where a wmoin was killed several miles way from where a rather short wife, was ainomg UPWARSD at water melon targets with her husbands 45, and the bullet flew several city blocks before killing the victim.

A bullet that would penetrate at best a few inches of soil wood or straw

A flywheel is the perfect shrapnel generator.

And dont stop to consider ice thrown off a wind turbine blade too long. A ballistics friend estimated 'lethal up to about 200 yards'

A girl I once knew woke up in hospital with concussions and a manufactured skull. The last thing she remembered was a lorry coming towards her. Police found a lump of broken brake drum inside the wreck of her car.. at only a few mph, that nearly killed her, and whe was lucky to escape the minor wreck that happened after she was knocked out..

Thats why I said 'tankfuls of petrol', not 'tanks, full of petrol'. a split tank of hyrdocarbon fuel will create a fuel air bomb.

The lead acid battery I personally explode was probably a hydrogen explosion due to overcharging, but it split the casing throwing sharp lumps of plastic all over the factory floor and spilled its acid guts everywhere. It was a forklift starter battery being charged overnight.

But I agree that in general batteries are discharge limited by internal resistance, so they just get hot and then explode on account of that - something I have seen happen with lithium cells quite a few times.

But then they are pissy little energy stores.

Gas is even more fun

I'd rather have 5000 tonnes of nuclear waste next door to me than one of these..

or 'the biggest chemical explosion ever' 500 tonnes of rocket fuel'

most casualtues from flying glass. well away from the blast

So energy storage is ..interesting..

If you are fan of hydro power, this one killed nearly the same number of people as chernobyl.

You will probably never have heard of it. How odd is that?

The last clip is a handy little device, ideal for taking out an offshore wind farm

(ignore the footage in the middle, its clearly from an entirely different test spliced in for dramatic effect).

True

but AFAICT that was not a spinny thing losing its bearings.

'killed more trout, than Chernobyl' would be nice strap-line

Indeed - I am very happy with the idea that a failing flywheel can be extremely dangerous. But differently dangerous to a dynamite explosion. Hence the conversion from standard units into sticks of dynamite is not really very helpful or illuminating.

Shrapnel - porter/ticket collector at Winchester got a nasty leg wound when a passing train kicked up a pandrol clip from the track. For the life of me, I cannot understand how it could have travelled from the track to where he was standing when hit. There appeared to be at least the edge-of-platform wall in the way!

I think your friend was being cautious - it could be much worse.

Imagine that a lump of ice comes off a blade, and that it's going at

Andy

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".

Did you miss the bit about the enclosure being evacuated?

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.

I wonder if you built the Severn Barrage if it could be used additionally for pumped storage?

I've seen a lead acid battery explode. It was on charge and someone disconnected it. The spark exploded hydrogen gas. The case was split and acid sprayed everywhere. Truck engine starter battery.

Killed 70 people. Turbine went off-balance due to combination of poor maintenance and being operated in a power output range which was not correct for the water level head at the time, and vibration destroyed top bearing mounting, promptly followed by most of the other turbines and the building.

This was after years of poor maintenance, and the turbine was 2 months short of its 30 year design life (not that it was about to be replaced).

There's loads on this incident in Wikipedia.

Dennis: tell the nurses that this time they have overdone the meds, and you are dribbling again.

# we couldn't make it that far. Using the same 200mph.

I'll have to recheck the calcs.

almost exactly the same as I saw. Cept it was a forklift truck.

Especially if it were 5000 metres high.

Both of these were small hydrogen explosions - nowhere near all the stored energy of the battery. This flywheel could easily dump the lot, in very short order..

Andy

taking figures for a 2.3MW turbine, 80m tower, 100m diameter blades

the height above ground levelof the blade tip when at 45 degrees from bottom, is 80 - (50 * sin 45) = 37 meters

feeding v0 = 90m/s, theta = 45, y0 = 37m into a handy trajectory calculator

give a range of 861m (but it ignores drag, so will be overstated).