Inside Electric Mountain: Britain's biggest rechargeable battery

[Chris Hogg]

To make that question sensible, you'd need to specify the height you're lifting it to.

[Mike Tomlinson]

En el artículo , AnthonyL escribió:

:)

Some would say that would be an improvement.

[Chris Hogg]

Here's a calculation (stepwise, for my benefit, and to allow it to be torn to shreds by those who can do it better, as I don't believe the result!).

The upper lake at Dinorwig is a little over 500 metres above the lower lake, so I'll assume a height of 500 metres.

1 tonne exerts 9806 Newtons of force.

The work done raising 1 tonne by 500 metres is 9806x500 = 4903000 Newton-metres.

A Joule is 1 Newton-metre, so the work done raising 1 tonne by 500 metres is 4903000 Joules.

This is achieved in 6 hrs, or 6x60x60 = 21600 seconds.

Units of power are Joules per second

So the power required is 4903000/21600 = 227 Joules per second.

A Joule per second is a Watt.

So the power required to raise 1 tonne by 500 metres in 6 hours is 227 Watts.

AIUI a typical domestic solar panel delivers 260 Watts at full blast.

So 1 panel should do it, with a little to spare.

I find that hard to believe! Where have I gone wrong?

[polygonum]

Nah - just import it from Portugal:

There are loads of solar panels covering enough of Wales already.

[Chris Hogg]

On the same page was linked this: Solar power sets new British record by beating coal for a day

Better start buying in stocks of candles and winter woollies!

[The Natural Philosopher]

Seems OK to me. 100 meters an hour is 27mm or a little over an inch a second.

A human being with a tackle can lift a tonne that fast easy.

In fact an Irish Navvy could shovel and lift 30 tonnes a day back in the

50's.

I think you are encountering the true meaning of 'energy density' - that a tonne of water up a hill is actually not really that interesting - maybe a couple of Kwh at best.

[The Natural Philosopher]

Well since coal is now pretty much off for the summer, that's not hard

[Mike Tomlinson]

En el artículo , polygonum escribió:

Yes, just seen that, thanks. Interesting.

In a country where it pisses down most of the time. Must make sense to

*someone*.

I saw a solar panel installation a couple days ago. On the gable end of a house. Pointing roughly north-east. With the gable end of the adjacent house about 6m away.

The installers must be laughing all the way to the bank. I'll take a pic next time I'm in the area.

[Mike Tomlinson]

En el artículo , Chris Hogg escribió:

Better still: emigrate to somewhere warm and sunny, like I did.

[Chris Hogg]

Thanks for the confirmation. Reversing the calculation, as it were, Dinorwig dumps 60 tonnes per second through its turbines, from a head of 500 metres and for a period of 6 hours. If 1 tonne moving through

500 metres in 6 hours is equivalent to 1 solar panel, Dinorwig is equivalent to 60x21600 solar panels, i.e. 1,296,000 panels. I'll leave it to AnthonyL to work out how much of Wales that would cover!

[The Natural Philosopher]

Actually insolation is on average about 100W/sq meter and a solar panel maybe gets to 25% efficiency, so 25W/sq meter on average. Obviously midsummer midday peaks are considerably higher - 10 x that.

IIRC Dinorwig can peak at 2GW, but not for 6h, thats less than a GW at that level.

At 4 sq meters per hundred watts, that's 40 sq meters for a killer-watt or 40 sq km for a gigawatt?

[polygonum]

Covering that much land by panels could be expected to have a significant impact on the shaded land.

Today I noticed a fairly substantial commercial building roof covered by panels. (A typical industrial estate cheap warehouse/factory/B&Q type of construction.) Strikes me that, so long as the panels are going to be deployed, those roofs are probably the most appropriate locations. Rather than a few square metres on each of hundreds or thousands of houses. Or covering up more land. Also might help to reduce maximum temperature in the building.

[Chris Hogg]

Hmm...yes, I see my mistake. It was in assuming a typical solar panel produce 260 Watts at full blast. That's a mfr's figure for peak output when insolated at 1000 Watts/sq.m. As you say, with insolation at 100 Watts/sq.metre and a conversion efficiency of 25% gives 25 Watts/sq.metre, so the answer to the OP's question is about 10 panels.

[Johnny B Good]

The 10 seconds figure I mentioned related to the time it took to open or close the giant penstock gate valve(s) feeding the turbines.

They don't use compressed air to keep them spinning whenever they need them in 'Hot Standby' running in air. The turbines use the generator as a motor to maintain synchronous speed so all that is required to change from motoring mode to generator mode is basically just a matter of "Turning on the tap" and adjusting the excitation current to raise the stator output voltage.

This rather neatly avoids the need to synchronise from a standing start but at a cost of 4MW per turbine. I'm afraid I can't recall whether all six turbine sets had this hot standby running in air capability or not. One thing is for certain, the 90MW turbine sets at Ffestiniog had no such hot standby feature, hence their much longer 60 seconds run up time.

[Mike Tomlinson]

En el artículo , Chris Hogg escribió:

I think the term would be "a metric fuckload".

[Huge]

The spinning reserve turbine is spun with electricity, not water.

[Mike Tomlinson]

En el artículo , Huge escribió:

I thought that was a made-up jap-sounding brand name stuck on awful hi- fi crap sold in the likes of Dixons and Currys in the '80s.

[Clive George]

My Matsui video still appears to be working :-) (I'd have not bought hi-fi with that brand though).

[Chris J Dixon]

Like this one?

Chris

[Mike Tomlinson]

En el artículo , Chris J Dixon escribió:

Yes, very much like that. I'm passing that way in the next couple of days, so will take a pic.