Scotland best for pumped-storage hydroelectricity dams to store wind energy economy [Archive]

Peter Dow

13-Mar-12, 20:10

This is a statement of the obvious as far as Scottish electrical power-generation engineers and scientists are concerned I expect but I am making this statement anyway, not for the benefit of our scientists or engineers but to inform the political debate about the potential of the Scottish economy "after the North Sea oil runs out" because political debate involves mostly non-scientists and non-engineers who need to have such things explained to them.

The Scottish economy has a profitable living to make in future in the business of electrical energy import/export from/to English electrical power suppliers and perhaps even to countries further away one day.

The tried and tested engineering technology we Scots can use in future to make money is pumped-storage hydroelectricity.

Wikipedia: Pumped-storage hydroelectricity (http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity)

The technique is currently the most cost-effective means of storing large amounts of electrical energy on an operating basis, but capital costs and the presence of appropriate geography are critical decision factors.

http://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Dam_at_Cruachan_reservoir.jpg/800px-Dam_at_Cruachan_reservoir.jpg

In Scotland, the Cruachan Dam pumped-storage hydroelectric power station (http://en.wikipedia.org/wiki/Cruachan_Dam) was first operational in 1966 and was built there to take advantage of Scotland's appropriate geography and available capital.

So Scotland has the appropriate geography for pumped-storage hydroelectric power and we have the capital particularly if we invest some of the taxes on North Sea oil before it all runs out and it is all spent.

Investment in wind-power energy generation is proceeding apace, in Scotland, in England, on and offshore, and that's very "green" and quite clever, though wind power is not as dependable as tidal power, but unless and until sufficient capacity to store energy becomes available to supply needs when the wind isn't blowing then conventional, and perhaps increasingly expensive, coal, gas or oil burning or nuclear energy power will still be needed to keep the lights on when the wind doesn't blow.

Scottish opportunity
Here is the opportunity for the Scottish economy in a future where wind-power generation is increasingly rampant: if we Scots build a large capacity of new pumped-storage hydroelectric power stations, not only can we supply all our own Scottish energy needs from "green" renewable energy schemes, but we could provide energy storage capacity for customers outside Scotland, particularly in England, who live in a land not so well endowed with appropriate geography for hydroelectric power.

In future, a Scotland with investment in a massive pumped-storage hydroelectric capacity could buy cheap English wind-power while the wind is blowing then sell the same energy back to English power suppliers, at a profit, when the wind isn't blowing and the English will pay more for energy.

So everyone wins, the energy is all green, the electricity supply is always available when it is needed and that is how the Scottish energy economy does very well after the North Sea oil runs out. :cool:

So problem solved but not job done as yet. We Scots do actually need to get busy investing and building pumped-storage hydroelectric power generation and supply capacity in Scotland now.

Peter Dow

13-Mar-12, 20:12

I am presenting here my vision for a large pumped storage hydroelectric 2-square kilometres surface-area reservoir and 300+ metre tall dam which I have designed for the Coire Glas site, Scotland.

(View site using Google Earth where the convenient label is "Loch a' Choire Ghlais" (http://tinyurl.com/coireglas) - or, http://tinyurl.com/coireglas)

I was inspired to conceive and to publish my vision by learning of the Scottish and Southern Energy (SSE) proposal to build a smaller hydroelectric pumped-storage scheme at Coire Glas (http://www.sse.com/CoireGlas/) which has been presented to the Scottish government for public consultation.

I have not long been aware of the SSE plan for the Coire Glas scheme, not being a follower of such matters routinely, but I was prompted by an earlier tangentially-related news story (about energy storage technology for renewable energy generators such as wind farms) to write to Members of the Scottish Parliament on the merits and urgency of new pumped storage hydroelectric power for Scotland on 14th February and a reply from Ian Anderson, the parliamentary manager for Dave Thomson MSP received the next day, the 15th February informed me about the SSE plan and Ian added "initially scoped at 600MW but, to quote SSE, could be bigger!"

I replied to Ian "So the schemes proposed by the SSE are welcome and ought to be green-lighted and fast-tracked, but I am really proposing that Scots start thinking long term about an order of magnitude and more greater investment in pumped storage hydroelectric capacity than those SSE plans."

So I had in mind "bigger would be better" but it was not until the next day on the 16th February when a news story informed me that the SSE plans had been submitted to the Scottish government for public consultation (http://www.bbc.co.uk/news/uk-scotland-highlands-islands-17061075) that I thought "this needs consideration now".

So starting late on the night of the 17th, early 18th February and all through the weekend, I got busy, outlining my alternative vision for a far bigger dam and reservoir at the same location.

So this is my vision as inspired by the SSE plan. If my vision is flawed then the fault is mine alone. If my vision is brilliant, then the brilliance too is mine.

http://scot.cyberhost.me/forum/media/peterdowcoireglasproposal.jpg

The black contour line at 550 metres elevation shows the outline of the SSE proposed reservoir of about 1 square kilometre surface-area and the grey thick line shows the position of the proposed SSE dam which would stand 92 metres tall and would be the tallest dam in Scotland and indeed Britain to date though it seems our dams are several times smaller than the tallest dams elsewhere in the world these days.

Part of the red contour line at 775 metres elevation, where the red line surrounds a blue shaded area, blue representing water, shows the outline of my larger reservoir of about 2 square kilometres surface-area and the thicker brown line shows the position of my proposed dam which would stand 317 metres tall which would be one of the tallest man-made dams in the world, 1475 metres long and about 72 million cubic metres in volume.

Enhanced satellite photograph

http://scot.cyberhost.me/forum/media/enhancedsatellite.jpg

Cross section of the Dow-dam
The Dow-dam would be more than 3 times higher than the proposed SSE-dam. In this diagram, a horizontal line one third of the way up the Dow-dam indicates the relative height of the SSE dam although it is not aligned with this cross-section.

http://scot.cyberhost.me/forum/media/dowdam.jpg

Peter Dow

13-Mar-12, 20:15

Maps showing the line of cross-section viewed from each side

http://scot.cyberhost.me/forum/media/damwatersidemap700.jpg

http://scot.cyberhost.me/forum/media/damdrysidemap700.jpg

Cross section of the Dow-dam reservoir

http://scot.cyberhost.me/forum/media/damcrosssectionmajordiameter.jpg

Cross section along the major diameter of the elliptical excavation of the reservoir bed

The Upper Reservoir

The green ellipse of major diameter of 1.5 kilometres and minor diameter of 1 kilometre represents an excavated reservoir bed, as flat and as horizontal as practical, at an elevation of 463 metres.

Since an excavated reservoir bed is not, that I can see, part of the SSE plan, at any size, I will provide some more information about my vision for that now.

The basic idea of excavating a flat or flattish reservoir bed is to increase the volume of the water stored in the reservoir because more water means more energy can be stored.

Capacity of the reservoir, energy stored and power supplied

Excavating around 138 million cubic metres of rock increases the volume of the reservoir so created to about 400 million cubic metres, achieving a theoretical energy storage capacity of more than 600 GigaWatt-Hours and it ought to be possible to excavate enough rock to achieve a practical 600GW.Hrs electrical energy supplied.

Accordingly, I envision it would be appropriate and useful to install the required turbine-pumps to supply up to 12 GigaWatts of electrical power to the grid for up to 50 hours before the energy store would be exhausted.

Excavation details

Depending on the geology and strength of the rock of Coire Glas the walls of the reservoir bed perimeter could be as steep as vertical from the reservoir bed up to the natural elevation of the existing rock surface which would mean, presumably, blasting out rock to create a cliff which at places could be as much as about 290 metres tall.

Near the dam, the reservoir bed perimeter wall would be only 40 metres or less tall. The further from the dam, the higher the wall will be and the more rock needs to be excavated.

A vertical reservoir bed perimeter wall would be ideal to maximise reservoir volume wherever the geology provides a strong stone which can maintain a vertical wall face without collapse, (a stone such as granite perhaps). Ideally this would allow about 138 million cubic metres to be excavated to flatten the reservoir bed.

Where the geology only provides a weaker stone then a sloping perimeter wall at a suitable angle of repose for reliable stability would be constructed.

So the reservoir perimeter wall could be as sloped as shallow as 45 degrees from the natural elevation at the perimeter of the eclipse sloping down to the reservoir bed at 463 metres elevation in the case of the weakest and most prone to collapse kinds of stone.

Exactly how strong the stone is at each location I guess we'll only find out absolutely for sure if and when engineers start blasting it and testing the revealed rock wall face for strength.

The shape of the perimeter of the excavated reservoir bed is not absolutely critical. So long as it ends up as a stable wall or slope, however it is shaped by the blasting, it will be fine. There is no need to have stone masons chip the perimeter smooth and flat! The ellipse is simply the easiest approximate mathematical shape to describe and to draw. If the end result is not a perfect ellipse, don't worry, it will be fine!

Peter Dow

13-Mar-12, 20:18

Loch Lochy and vicinity water flow control works

Here is an annotated satellite photograph of the land south from Coire Glas showing Loch Lochy, Loch Arkaig, the isthmus between the lochs, Mucomir where Loch Lochy empties into the River Spean before it flows on as the River Lochy, the Caledonian Canal and Fort William where the river flows into a sea loch.

http://scot.cyberhost.me/forum/media/lochywater768.jpg

New waterway

Loch Lochy (http://en.wikipedia.org/wiki/Loch_Lochy) is separated from a neighbouring loch, Loch Arkaig (http://en.wikipedia.org/wiki/Loch_Arkaig), by a 2 km wide isthmus, which I have identified on this map (http://postimage.org/image/3jw6j3bxp/) as "the Achnacarry Bunarkaig isthmus", after the local place names.

It ought to be quite straight forward to build a canal or culvert, to connect those two lochs. The idea is that the new waterway would be wide and deep enough, enough of a cross section area under water, perhaps hundreds of square metres, so as to allow free flow from one loch to the other, so as to equalise the surface elevations of the two lochs, so as to increase the effective surface area of Loch Lochy so as to decrease the depth changes to Loch Lochy when water flows in from the Coire Glas reservoir when it discharges water when supplying power.

Now, Loch Arkaig has a natural surface elevation of 43 metres and this would be lowered to that of Loch Lochy. The surface area of Loch Arkaig is given by wikipedia as 16 km^2 also, (though it looks to me somewhat smaller than Loch Lochy). In addition, partially draining Loch Arkaig to bring its level down to that of Loch Lochy will also reduce its surface area.

If say, the additional surface area of Loch Arkaig is about 10 km^2 added to Loch Lochy's 16 km^2 this would give an effective surface area of 26 km^2 and reduce the potential depth variation to

Potential depth variation of Loch Lochy + Loch Arkaig = 400 000 000 m^3 / 26 000 000 m^2 = 15.3 metres.

Without equalising the loch levels, the depth changes to Loch Lochy that would require to be managed may be potentially more like 25 metres than 15 metres. So the new waterway is an important part of the new water flow control works that Coire Glas/Dow requires to be constructed.

Additional Loch Lochy water level control measures

When the Coire Glas reservoir is full, then the water level of Loch Lochy should be prevented, by new water works - drains, dams, flood barriers etc. - from rising due to rainfall and natural flow into the loch above a safe level which allows for the reservoir to empty into the loch without overflowing and flooding.

The safe "upper-reservoir-full" loch level will likely turn out to be around about 15 metres below the maximum loch level.

The next diagram showing the new loch drain and the reservoir pump inlets indicates how this might be achieved.

http://scot.cyberhost.me/forum/media/lochyflow768.jpg

The drain from Loch Lochy to the sea which goes underground from the 14 m elevation level in the loch would need capacity for the usual outflow from Loch Lochy which currently goes through the Mucomir hydroelectric station.

I have estimated the flow through Mucomir from its maximum power of 2MegaWatts and its head of 7m as somewhere near 0.2 Mega-cubic-metres-per-hour and compared that value using a spreadsheet I have written to predict the capacity of water flow through different sizes of drains using the empirical Manning formula (http://en.wikipedia.org/wiki/Manning_formula) and this is also useful for determining the appropriate size of the new water channel between the lochs.

Ease my quantity :D

To construct Coire Glas/Dow/600GW.Hrs/12GW may cost of the order of around £20 billion, but that would be my order of magnitude educated guess more than a professional cost estimate.

In other words, I'm only really confident at this early "vision" stage that the cost would be closer to £20 billion than it would be to £2 billion or to £200 billion but I'm not claiming to be able to quote an accurate cost estimate at this stage.

I have not itemised my costs - how much for land, how much for labour, how much for trucks, how much for diggers, how much for cement, how much to install the generators etc. and the SSE have not published itemised costs for theirs either so I can't calculate my costs in a proportion to the SSE's costs.

Although my version offers 600 GigaWatt-Hours energy and 12 GigaWatts power (or 20 times the capacity and performance) some of the items in my version would cost more than "in proportion", in other words more than 20 times the SSE's cost.

For example, the cost of my dam will be more like 27 times the cost of the SSE's dam. (3.44 times higher and thicker and 2.27 times longer).

For example, the cost of excavating 400 million tonnes of rock from the reservoir bed to increase the capacity of the reservoir to hold water (and energy) in my version won't be in proportion to the SSE costs for excavating their reservoir bed because, as far as I know, they don't plan to excavate their reservoir bed at all.

On the other hand, my land costs are about the same as the SSE's - much less than in proportion. I may well need to use more land to dispose of the additional excavated rock spoil but perhaps when that additional land has been landscaped over it could be resold?

So it depends how much the land is as a proportion of the SSE's costs. If land is a small part of their costs, if 20 similar sites to build on are just as cheap and easy to buy then my costs will be much more than proportional, since saving land won't save much money.

If land is scarce and valuable and the cost to purchase suitable land with a good chance to get permission to build on it is a significant proportion of the SSE's or anyone's costs to build 20 of their size of hydro dam schemes then my costs may be better than proportional. Sometimes securing suitable land for development can be very problematic, very expensive. Sometimes people won't sell their land. Sometimes the authorities won't agree that the land can be used in this way.

The SSE say that suitable sites for such pumped storage schemes are rare indeed, so land costs may be very significant and my scheme good value for money.

If indeed the cost of my scheme is somewhere around £20 billion it is likely to cost far more than the SSE or any electrical power supply company looking to their annual profits for the next few years could possibly afford.

Something like £20 billion I expect could only be found as a national public infrastructure project, spending government money, like the building of a large bridge or motorway would be.

A £20 billion government project would require Treasury approval, at least while Scotland is ruled as part of the UK.

I have suggested funding my much larger hydro dam scheme by re-allocating of some of the Bank of England's "Quantitative Easing" funds which amount to some £300 billion of new money printed with not much to show for it.

Any Questions?

OK, well I guess that's the vision part over. The rest is fairly straight-forward engineering I hope. Oh, and there is always getting the permission and the funding to build it of course which is never easy for anything this big.

OK, well if anyone has any questions or points to make about my vision or can say why they think the SSE plan is better than mine, or if you don't see why we need any pumped storage hydroelectric scheme at Coire Glas, whatever your point of view, if you have something to add in reply, please do.

Bobinovich

13-Mar-12, 20:38

You've obviously gone to some trouble but I've got to ask - why here, on C.org :confused? Surely the plan should be put to SSE or the Scottish Government where its merits etc. can be looked at by professionals in the field...

Peter Dow

13-Mar-12, 21:39

You've obviously gone to some trouble but I've got to ask - why here, on C.org :confused?
Someone here might be interested.

Surely the plan should be put to SSE or the Scottish Government where its merits etc. can be looked at by professionals in the field...
I have been putting my plan to any and all, not least to fellow scientists, engineers, the SSE and the Scottish government. But I have also been taking my plan to those with an interest - the Scots, highlanders, hill walkers, whoever might have a view.

Even if the SSE loved my plan for a 600GW-hour hydro scheme it is too big a project for them to consider building anything that size without government funding making it an infrastructure project, like the building of a big bridge or motorway.

So I am not going to the SSE and expecting them to "yes" or "no" it and fund it themselves. That would be like going to NASA before President Kennedy had decided to put a man on the moon and expecting NASA to take a final decision on it. The decision to go to the moon was a political one, not a decision only for NASA.

It is now a political decision before the Scottish government whether to just go with the smaller SSE plan for a 30GW-hour plan, which they could fund from their own funds. I am promoting my plan widely to get the idea of a much bigger hydro scheme into the public discourse, for government consideration and possible funding.

So when it is something this political it really does matter to try to get support from the people, not just the professionals and politicians.

Corrie 3

13-Mar-12, 21:49

Phill

13-Mar-12, 22:20

Well, have word with China! Mr Salmond is already paving the way, and they do do dams.

secrets in symmetry

13-Mar-12, 22:43

Amazing! This thread is nowhere near as crazy as I expected! :cool:

I'm not a civil engineer and I don't know whether the proposed plan is remotely feasible (or just plain bonkers!), but energy storage on this scale is essential if a lot of our energy needs are to be fulfilled by wind, waves and tides.

Gronnuck

13-Mar-12, 23:40

Wearing my Cynic hat - does this mean that my electrickery bill is going to rise again to subsidise another green project like those winymill thingys?

Peter Dow

14-Mar-12, 00:27

Have you put your plan direct to Alex Salmond? I don't mean his minions, I mean direct!!
You mean did I email Alex.Salmond.msp@scottish.parliament.uk ? Yes sure, when I emailed all the MSPs only a very few replied. These MSPs get loads of emails all the time.

I also emailed ministers responsible for energy to scottish.ministers@scotland.gsi.gov.uk addressing it to John Swinney and Fergus Ewing. I got a reply on the ministers' behalf from the Scottish civil servant Paul Smith at the Energy Division and Renewables Road Map team of the Scottish government.

It's so refreshing to see such idea's on here instead of those who are pretend/wannabee scientists and think they know everything.

Ben Cruachan has served well, a bigger one would be fantastic!!

C3.....................:)
Thanks! :D

Peter Dow

14-Mar-12, 00:32

Well, have word with China! Mr Salmond is already paving the way, and they do do dams.
Hmm. :confused The Chinese are doing dams better these days than they did in 1975,

Wikipedia: (http://en.wikipedia.org/wiki/Banqiao_Dam)Banqiao Dam

(http://en.wikipedia.org/wiki/Banqiao_Dam)The Banqiao Reservoir Dam is a dam on the River Ru in Zhumadian Prefecture, Henan province, China. It infamously failed in 1975, causing more casualties than any other dam failure in history, and was subsequently rebuilt.
The Banqiao dam and Shimantan Reservoir Dam are among 62 dams in Zhumadian Prefecture of China's Henan Province that failed catastrophically or were intentionally destroyed in 1975 during Typhoon Nina.
The dam failures killed an estimated 171,000 people; 11 million people lost their homes.

:(
I think I'll put my faith in Scottish engineering if that's OK with you.

ywindythesecond

14-Mar-12, 00:43

I hate to put a damper on this but the limiting factor is how much rain falls on the reservoir and its catchment area and how fast will it be replenished when used?

secrets in symmetry

14-Mar-12, 00:48

I hate to put a damper on this but the limiting factor is how much rain falls on the reservoir and its catchment area and how fast will it be replenished when used?Lol!

Yet another schoolboy error from our local project boy.

How can you miss the point so badly lol?

Peter Dow

14-Mar-12, 00:49

Wearing my Cynic hat - does this mean that my electrickery bill is going to rise again to subsidise another green project like those winymill thingys?
My scheme doesn't mean that no. Electricity bills would not pay for my scheme, at all.

My scheme involves running this as a government infrastructure project and getting new money printed to pay for it something like the same as the Bank of England's "Quantitative Easing" money, of which they've dished out £325 billion to their bust pals in the city who have gone bust making bad investments and so now they need to get bailed out with £325 billion worth of newly printed money by Sir Melvyn King, "the governor".

Only the billions I would need for this would go into building something worthwhile not funding casino gambling on the money markets.

The way the kingdom seems to me to work is that if you are a professor of economics from Cambridge University with a knighthood like Sir Melvyn they make you Governor of the Bank of England and let you print as much new money to give to your broke city pals as you like.

But if you are a republican scientist with good ideas for the economy, they don't give you anything except a nice police cell for the night if you don't shut up when asked. :roll:

Peter Dow

14-Mar-12, 01:06

I hate to put a damper on this but the limiting factor is how much rain falls on the reservoir and its catchment area and how fast will it be replenished when used?
Eh no. The upper reservoir is filled by pumping water up from the loch below.

This is not a conventional hydro-electricity scheme. This scheme will not be used as a primary source of energy. It is used only as a store for any surplus energy generated from renewable sources such as wind farms.

Of course the lochs are filled up with rain water but the proportion of water you need from the loch just gets pumped up to the upper reservoir then later comes down through the turbines. So the water doesn't really get used up, it's just gets circulated up and down and there is plenty of water in the loch, though my scheme does admittedly use two lochs to lessen the depth changes involved with the much bigger volume of water used.

Phill

14-Mar-12, 11:54

Hmm. :confused The Chinese are doing dams better these days than they did in 1975Not really, the Three Gorges seems to have a lot of question marks about it. (sorry, couldn't find the tongue in cheek smiley)
I think I'll put my faith in Scottish engineering if that's OK with you.Sounds excellent to me, no buying steel from China or German contractors to build it!?

Rheghead

14-Mar-12, 19:41

Corrie 3

14-Mar-12, 19:46

Lol!

Yet another schoolboy error from our local project boy.

How can you miss the point so badly lol?
Yet another Big-Head "I know it all" post from our very own Sis-sy!!!!!
Mr Bloody Perfect !!!!

C3......................:eek::eek:

Peter Dow

14-Mar-12, 20:51

Not really, the Three Gorges seems to have a lot of question marks about it. (sorry, couldn't find the tongue in cheek smiley)
Not really better than the 171,000 killed in the 1975 Chinese dam disaster? :confused

Sounds excellent to me, no buying steel from China or German contractors to build it!?
Well if it is my scheme, if I am in charge of running it, if I'm allowed to get printed as many pounds Sterling by the Scottish and British governments as I need then sure I could guarantee to use only Scottish and British suppliers for steel and other materials so long as they can supply in quantity and quality.

I might need so much steel that even at full production the British steel industry can't produce enough then I might need to look abroad to get the quantity in time I need.

If I am not getting the billions in new Sterling I need then it would all depend who is prepared to print their currency for this because he who pays the piper calls the tune.

I've no reason to suppose the European central bank would be more generous than the Bank of England as neither have yet said to me - "OK Peter, there's the £20 billion you need for your hydro dam scheme."

But if say the Bank of England and UK Treasury said "no way" but then the Euro Bank said "no problem" then they might have a rule that says if you use European funding then you must use European suppliers on an equal basis.

I've no reason to suppose the Chinese would be the only ones to step in to fund it but if there was no-one else and they did offer, again maybe they'd impose conditions on using Chinese steel or Chinese something else?

The one thing I would never compromise on is quality, of the steel or of anything else.

I would be demanding something like an expected operational life span of my dam of about 10,000 years even if my dam is the only construction in Scotland that lasts 10,000 years.

So that means mild steel rebar is out for the reinforced concrete for the dam. This isn't something that can be allowed to slowly rust and get weaker with the years.

Phill

14-Mar-12, 23:45

Not really better than the 171,000 killed in the 1975 Chinese dam disaster?No, the potential is far worse when it goes tits up.
Well if it is my scheme, if I am in charge of running it..............I would be demanding something like an expected operational life span of my dam of about 10,000 years even if my dam is the only construction in Scotland that lasts 10,000 years.It's a question of the business plan. If this means 'we' can provide huge amounts of energy at the flick of a switch at any moment 24/7, and that energy is 'Green' energy then a business plan should be a piece of cake, no need to get people to print money. As for 10,000 year structure, pointless. Next to impossible and puts your costs into space. And for material supplies, I like your thinking but, Scotland, UK, Britain or whatever needs to take a different approach to infrastructure builds: demand that it is supplied by Scot/UK provider. Don't prat about borrowing money on international markets where the UK taxpayer picks up the bill and then spend the money on the other side of the world pretending it's saving us money. Keep it circulating locally, more jobs & less taxes.

Errogie

15-Mar-12, 00:02

Have you any thoughts about where and how to get rid of 138 million tonnes of excavated rock?

Phill

15-Mar-12, 00:13

Have you any thoughts about where and how to get rid of 138 million tonnes of excavated rock?Sell it! Use it it the dam wall. Casually scatter it about down yer trooser legs Great Escape stylee.

secrets in symmetry

15-Mar-12, 00:36

I like the ambition of the design. However I am doubtful of the geology and the physical properties of any dam wall that is capable of holding up to the job. You've got the valley absolutely brim full of water and the dam wall is attached right on the 'lip' of the valley rather than set in a little way further up the valley. Presumably to maximise storage?

The designer's adage 'if it looks alright, it'll be alright' saves a lot of calculations involving masses, moments and stresses, and in this case it doesn't for me, but then I'm not a civil engineer. Perhaps a scheme that is some where between the SSE proposal and yours could be more convincing?

In any case, such a scheme would be useful to help manage the variability of renewable sources but perhaps not essential. Dr David JC Mackay, the CHief Scientific advisor to DECC explains in his book 'Energy without the hot air' that when output of renewable sources exceeds demand then it will be possible to store the excess by means of charging up electric vehicle batteries.Charging millions of car batteries on windy nights is a fine idea, but it's generally not good policy to put all your eggs into one basket. Massive pumped storage would complement car batteries rather well - and we would need truly massive storage in David Mackay's carbon-free energy scenarios.

I share your doubts about the feasibility of the dam, not to mention digging a giant swimming pool up a hill, and then using it to raise and lower the level of two large lochs by tens of metres!

Peter, have you considered how you would arrange your pipes between the upper and lower reservoirs? How many do you need, and what radii would they have? How fast would the water be flowing when it reaches your generators? Where would you place the generators, and how many would you need? How quickly can you pump a reservoir full of water back up the hill?

ywindythesecond

15-Mar-12, 00:40

Yet another Big-Head "I know it all" post from our very own Sis-sy!!!!!
Mr Bloody Perfect !!!!

C3......................:eek::eek:

Thanks Corrie but Sis is right. My answer was perfect for conventional hydro, not for pumped storage. W&M syndrome is to blame.
However, if the enlarged storage Peter proposes is to help balance the peaks and troughs of wind generation, then it is fine for balancing the trough that comes along but the the reservoir cannot be replenished until another wind peak comes along, unless Longannet etc, relegated to standby generation and kept hot in case needed, is fired up to pump water uphill so we can enjoy overpriced wind energy when it is available, and have a Plan B when it is not.

Think about it. Invest in pumped storage to support erratic wind generation which relies on the erratic wind generation to fuel it.

secrets in symmetry

15-Mar-12, 01:11

Thanks Corrie but Sis is right. My answer was perfect for conventional hydro, not for pumped storage. W&M syndrome is to blame.Much kudos to you for posting that. :cool:

However, if the enlarged storage Peter proposes is to help balance the peaks and troughs of wind generation, then it is fine for balancing the trough that comes along but the the reservoir cannot be replenished until another wind peak comes along, unless Longannet etc, relegated to standby generation and kept hot in case needed, is fired up to pump water uphill so we can enjoy overpriced wind energy when it is available, and have a Plan B when it is not.

Think about it. Invest in pumped storage to support erratic wind generation which relies on the erratic wind generation to fuel it.Yes, you're right about wind plus pumped storage not being a panacea - unless (even if?) you have massive overcapacity in wind generation, which would be a tad crazy. Tidal is easier to balance because it's predictable years in advance - but it's not there yet. It will be a difficult balancing act whichever way we choose to go in the brave new carbon-free world of the near future.

Roll on LIFE! Well, we can but hope....

ywindythesecond

15-Mar-12, 01:24

Much kudos to you for posting that. :cool:

Yes, you're right about wind plus pumped storage not being a panacea - unless (even if?) you have massive overcapacity in wind generation, which would be a tad crazy. Tidal is easier to balance because it's predictable years in advance - but it's not there yet. It will be a difficult balancing act whichever way we choose to go in the brave new carbon-free world of the near future.

Roll on LIFE! Well, we can but hope....
Goodness me, a meeting of minds!
However, the timing of tides is predictable, but not their strength.

Peter Dow

15-Mar-12, 02:02

I like the ambition of the design.
Thanks.

However I am doubtful of the geology
Well it is pretty standard practice to get a geological survey of the area before a major construction is done and if it turns out to be unsuitable to build on it won't proceed but my educated guess is that if the land is suitable to build the SSE's dam it'll also be suitable for mine.

Coire Glas is itself a colossal geological structure and if it was weak rock it would have collapsed long ago or been weathered away. It looks like tough rock to me but I'll be sure to get it checked out by the geologists.

and the physical properties of any dam wall that is capable of holding up to the job.

Well there's no secret to the science and engineering of building dams.

If you are interested you could start learning all about it here - Wikipedia: Dam
(http://en.wikipedia.org/wiki/Dam)

You've got the valley absolutely brim full of water and the dam wall is attached right on the 'lip' of the valley rather than set in a little way further up the valley. Presumably to maximise storage?
Ye-e-ss. :roll:

The designer's adage 'if it looks alright, it'll be alright' saves a lot of calculations involving masses, moments and stresses, and in this case it doesn't for me, but then I'm not a civil engineer.
Yes well if and when there's a model of my dam made to show you what it will look like then you can reasonably say if it "does it for you" or not but right now you are only looking at a line on a graph showing the position of the dam and a cross section diagram which doesn't give you any idea really of the three dimensional shape of the dam.

Perhaps a scheme that is some where between the SSE proposal and yours could be more convincing?

No my dam is not going to rely for its strength on its "attachment" to the side walls of Coire Glas but from its solid anchoring to the ground below. So there's no need to push it further up the valley.

In any case, such a scheme would be useful to help manage the variability of renewable sources but perhaps not essential. Dr David JC Mackay, the CHief Scientific advisor to DECC explains in his book 'Energy without the hot air' that when output of renewable sources exceeds demand then it will be possible to store the excess by means of charging up electric vehicle batteries.
No sorry we can't wait for however many decades it will be, if ever, for everyone to have an electric car with batteries that could do that.

Peter Dow

15-Mar-12, 03:08

No, the potential is far worse when it goes tits up.
Shouldn't you have said "if it goes tits up"? Don't you think the Chinese might have designed their dams properly this time?

It's a question of the business plan. If this means 'we' can provide huge amounts of energy at the flick of a switch at any moment 24/7, and that energy is 'Green' energy then a business plan should be a piece of cake, no need to get people to print money.
Apparently not. Even the SSE are in no hurry to build their much smaller scheme at Coire Glas.

BBC: SSE plans new £800m hydro electric storage scheme in Great Glen
(http://www.bbc.co.uk/news/uk-scotland-highlands-islands-17061075)
SSE Renewables said is would be looking for a change in transmission charges before pressing ahead.

Telegraph: SSE says independence referendum is creating economic "uncertainty (http://www.telegraph.co.uk/news/politics/9104876/SSE-says-independence-referendum-is-creating-economic-uncertainty.html)"

The independence referendum is endangering the Scottish economy after one of the country’s largest businesses confirmed “uncertainty about the future” is affecting its investment plans.

By Simon Johnson, Scottish Political Editor
6:00AM GMT 25 Feb 2012

SSE, previously known as Scottish and Southern Energy, said it has “no alternative” but to take into account the “additional risk” of separation when deciding whether to press ahead with energy projects north of the Border.

Although the company will not declare a moratorium on an estimated £3.5 billion of schemes that are already in the pipeline, the referendum makes it less likely they will get the go-ahead.

SSE said this situation will continue until the ballot is held and, in the event of independence, it becomes clear whether the British Government will continue to subsidise a separate Scotland’s green energy industry.

However, such a lengthy delay would destroy the First Minister’s hope of turning Scotland into green energy powerhouse by the end of the decade. His targets rely on rapidly building new offshore wind and wave farms, the projects that are most at risk.

The intervention by SSE, Scotland’s second largest company, is also extremely embarrassing for Mr Salmond after he poured scorn on the Chancellor of the Exchequer’s claims the referendum is damaging the economy.

It further increases pressure on him to bring forward his preferred autumn 2014 date for the referendum. Michael Moore, the Scottish Secretary, this week set out an alternative timetable to stage the ballot in September 2013.

The SSE warning echoed a similar report by banking giant Citigroup, which was also dismissed by the SNP, that companies should exercise “extreme caution” over investing in Scotland before the vote takes place.

Peter Atherton, Citigroup’s energy market analyst, last night told the Daily Telegraph the prospect of Scottish separation is now being raised with him by worried investors at every meeting he holds, whether in Switzerland or the US.

SSE outlined its concerns in an official submission to separate consultations on the referendum being staged by the Coalition Government and Scottish Executive.

Although the company did not express a view on independence, the company said Britain should retain a single energy market regardless of the referendum’s result.

This is because energy companies rely on subsidies paid by all 27 million UK households to fund new projects. However, there is no guarantee this situation would continue after separation, creating “additional uncertainty about the future”.

"This additional risk will apply up to the date of the referendum” and would continue until any separation negotiations between London and Edinburgh are concluded, SSE said.

In the meantime, the uncertainty could cause the company to deduct a “risk premium” from the level of income it expects to generate from future energy projects.

Its directors will then “have to assess the impact of that premium on whether or not to proceed with the investment proposal.” Although existing projects will continue to be developed, they may no longer get final approval.

Mr Atherton welcomed the intervention and said energy companies have come under pressure from shareholders following international publicity about the referendum last month.

“They (SSE) will carry on with their onshore wind farm programme because that can be done before the referendum, but the offshore projects are the ones that will deliver the Scottish government’s renewables policy,” he said.

“It’s these projects SSE are saying they cannot go ahead with until they know the outcome of the referendum.”

Mr Moore last night said the company had made a “crucial point”. He said: “SSE’s submission adds considerable weight to the case for having the referendum sooner rather than later.”

Johann Lamont, the Scottish Labour leader, said: “This significant intervention demonstrates the growing uncertainty the delay over the referendum is creating.

“With a national crisis in unemployment in Scotland, we cannot afford for business to shelve or delay plans to wait to see if we are remaining in the United Kingdom.”

Ruth Davidson, her Tory counterpart, added: “Our businesses need clarity about their future, yet the SNP are refusing to provide this by dragging the process out until 2014. This is simply not good enough.”

But SNP ministers said the submission was “extremely positive” because SSE said it had no plans to move from its Perth headquarters and is committed to “ongoing investment” in Scotland.

Fergus Ewing, the Energy Minister, said: “We agree with SSE that post-independence we should maintain a single Great Britain energy market, within an increasingly unified single EU market.”

This opportunity to invest for the future is not a time for "business plans". It is an opportunity and a time for strategic economic leadership by government.

As for 10,000 year structure, pointless. Next to impossible and puts your costs into space.
Really?

http://upload.wikimedia.org/wikipedia/commons/thumb/a/af/All_Gizah_Pyramids.jpg/800px-All_Gizah_Pyramids.jpg
http://en.wikipedia.org/wiki/Giza_pyramid_complex

http://upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Great_Wall_of_China_July_2006.JPG/800px-Great_Wall_of_China_July_2006.JPG
http://en.wikipedia.org/wiki/Great_Wall_of_China

http://upload.wikimedia.org/wikipedia/commons/thumb/3/3f/QtubIronPillar.JPG/445px-QtubIronPillar.JPG
http://en.wikipedia.org/wiki/Iron_pillar_of_Delhi

Admittedly, none of those have lasted 10,000 years. Yet.

Anyway, the Space Station is only costing about $60 / £40 billion. Space is not so expensive. We need to have a President Kennedy attitude - "We choose to go to the moon and do the other things not because they are easy but because they are hard".

Renewable energy should be Scotland's "race to the moon". We come in peace for all mankind.

And for material supplies, I like your thinking but, Scotland, UK, Britain or whatever needs to take a different approach to infrastructure builds: demand that it is supplied by Scot/UK provider.
If you pay then you can demand.

Don't prat about borrowing money on international markets where the UK taxpayer picks up the bill and then spend the money on the other side of the world pretending it's saving us money.
You're the one who mentioned Germany and China. They're not my worry. They are your worry. I was addressing your worries.

Keep it circulating locally, more jobs & less taxes.
OK, then show me the money and I'll get it circulating locally to create jobs to build this hydro dam scheme.

Peter Dow

15-Mar-12, 03:35

Have you any thoughts about where and how to get rid of 138 million tonnes of excavated rock?
Actually it is more like 400 million tonnes of rock that will need excavating for my size of scheme.

Note I wrote "138 million cubic metres" and rock is a lot more dense than water so it is more like 1 cubic metre of rock weighs about 2.7 tonnes.

Capacity of the reservoir, energy stored and power supplied

Excavating around 138 million cubic metres of rock increases the volume of the reservoir so created to about 400 million cubic metres,

In addition to that 138 there might be another 9 million cubic metres of rock that needs excavating from under the reservoir to create the tunnels to the turbine pumps.

So say 147 million cubic metres of rock which will probably weigh in at something just short of 400 million tonnes.

Some of this excavated rock can be crushed to make into aggregate for the concrete to make the dam. The rest that is surplus to requirements can go as landfill and be covered over, landscaped and the land reused.

Peter Dow

15-Mar-12, 03:47

I share your doubts about the feasibility of the dam, not to mention digging a giant swimming pool up a hill, and then using it to raise and lower the level of two large lochs by tens of metres!
More like only 15 metres rather than "tens of metres".

Peter, have you considered how you would arrange your pipes between the upper and lower reservoirs? How many do you need, and what radii would they have? How fast would the water be flowing when it reaches your generators? Where would you place the generators, and how many would you need?
No. You can get a rough idea of how its done by looking at the SSE's plan for theirs.

Check out the SSE's pdf file "Board 8, Indicative Layout of Underground Complex".
(http://www.sse.com/uploadedFiles/Z_Microsites/Coire_Glas_Hydro_Scheme/Controls/Lists/Resources/Sheet%208.pdf)
I presume the SSE in turn lifted their plans from previous pumped-storage schems such as Cruachan.

How quickly can you pump a reservoir full of water back up the hill?
For my scheme 70 hours at the full power rating of the pumps but actually the water will only be pumped up as and when there is surplus power available and that will depend on such factors as how windy it is.

Peter Dow

15-Mar-12, 03:56

Thanks Corrie but Sis is right. My answer was perfect for conventional hydro, not for pumped storage. W&M syndrome is to blame.
However, if the enlarged storage Peter proposes is to help balance the peaks and troughs of wind generation, then it is fine for balancing the trough that comes along but the the reservoir cannot be replenished until another wind peak comes along, unless Longannet etc, relegated to standby generation and kept hot in case needed, is fired up to pump water uphill so we can enjoy overpriced wind energy when it is available, and have a Plan B when it is not.

Think about it. Invest in pumped storage to support erratic wind generation which relies on the erratic wind generation to fuel it.
The idea would be eventually to have enough wind and other renewable generators and enough pumped-storage hydro that you can smooth out even the largest peaks and troughs of wind power.

Ideally, you would not need to keep the likes of big coal fire stations hot. You should have some fast starting gas power back-ups for freak weather events. Maybe keep Longannet in moth-balls in case there is a huge earthquake that knocks over all the wind turbines or some other catastrophic emergency we can't think of right now.

ywindythesecond

15-Mar-12, 09:50

The idea would be eventually to have enough wind and other renewable generators and enough pumped-storage hydro that you can smooth out even the largest peaks and troughs of wind power.

Ideally, you would not need to keep the likes of big coal fire stations hot. You should have some fast starting gas power back-ups for freak weather events. Maybe keep Longannet in moth-balls in case there is a huge earthquake that knocks over all the wind turbines or some other catastrophic emergency we can't think of right now.

Extract from "Analysis of UK Wind Generation November 2008 to December 2010"

"PUMPED STORAGE HYDRO

Pumped storage hydro is frequently cited as the solution to long periods of low wind output. However, if all four UK pumped storage plants were to be run simultaneously at full capacity, the stored water would be exhausted in around 24 hours. Once exhausted, the reservoirs can only be replenished when there is a surplus of generation over demand, and it takes longer to replenish the reservoirs than it does to empty them.

UK PUMPED STORAGE CAPACITY

Plant
Dinorwig
Ffestiniog
Cruachan
Foyers

Capacity
1728MW
360MW
400MW
300MW

Duration at peak output
5 hours
20 hours
22 hours
Not found

No details of the period at which Foyers can run at full capacity were found, but at a massive flow of 100m³ per second, it is not likely to be of long duration.

The existing 2788MW of installed UK pumped storage hydro plays a key role in balancing the grid. If it is to be used as a replacement for wind in windless times, then it cannot do its current job as well.

Scottish and Southern Energy have announced plans to construct two pumped storage schemes near Loch Ness with capacity of 600-1200MW between them, and have Planning Consent for 60MW at Loch Sloy, near Loch Lomond.

All three new schemes are designed to help meet peak demand. If they were to be used as back-up for wind in protracted low output periods, they would have the same limitations on duration of supply and would be unable to fulfil the purpose for which they are to be built.

It would require the approximate equivalent output of three Cruachan Power Stations (400MW) to replace 1000MW of wind-generated energy for one day. [(1000MW x 24 hours) ÷ (400MW x 22 hours) = 2.72.] The logistics of backing up wind energy with pumped storage hydro are such that even if there were enough suitable locations, the scale and cost of the Civil Engineering exercise to construct it would be prohibitive."

Errogie

15-Mar-12, 12:30

Rheghead

15-Mar-12, 18:42

In the documentary 'Life after People', the Hoover Dam survives for 10,000 years. Quite encouraging then?

Peter Dow

16-Mar-12, 03:25

However I am doubtful of the geology

Well it is pretty standard practice to get a geological survey of the area before a major construction is done and if it turns out to be unsuitable to build on it won't proceed but my educated guess is that if the land is suitable to build the SSE's dam it'll also be suitable for mine.

Coire Glas is itself a colossal geological structure and if it was weak rock it would have collapsed long ago or been weathered away. It looks like tough rock to me but I'll be sure to get it checked out by the geologists.

Geology of the Coire Glas site
I have been able to extract this information from the British Geological Survey (BGS) Geology of Britain viewer, (http://mapapps.bgs.ac.uk/geologyofbritain/home.html) from the 1:50 000 scale map.

http://scot.cyberhost.me/forum/media/coireglashydrogeology800.jpg

http://s15.postimage.org/uoxc2j8p3/coireglashydrogeology.jpg (http://postimage.org/image/uoxc2j8p3/)
Click to see larger image (http://postimage.org/image/uoxc2j8p3/)

According to this map, the bedrock at the site which would be used to build the dam on top of and to extract rock from to create the tunnels for the underground complex seems to be a rock geologists call "psammite (http://en.wikipedia.org/wiki/Psammite)" which I understand to mean here "a metamorphic rock whose protolith was a sandstone".

What neither the map nor the "psammite" name is telling us is how fractured the psammite rock there is and therefore how strong and also how impermeable or otherwise to water this rock is likely to prove to be, both of which would be interesting for any engineers building a pumped-storage hydro dam scheme there to know.

What does look fairly obvious to me is that the superficial deposit of what the map calls "hummocky (moundy) glacial deposits - diamicton, sand and gravel" would not be strong enough, nor impermeable enough to build any dam on top of and at least along the line of the dam, this glacial deposit ought to be removed to get down to the bedrock within which to establish the foundations of the dam, although I would think that this glacial deposit might be made into aggregate to make the concrete for the dam by the sounds of it.

secrets in symmetry

16-Mar-12, 23:17

Goodness me, a meeting of minds!
However, the timing of tides is predictable, but not their strength.Lol!

The strength of tides is predictable to within weather-dependent limits. What more do you want?

secrets in symmetry

16-Mar-12, 23:24

No. You can get a rough idea of how its done by looking at the SSE's plan for theirs.

Check out the SSE's pdf file "Board 8, Indicative Layout of Underground Complex".
(http://www.sse.com/uploadedFiles/Z_Microsites/Coire_Glas_Hydro_Scheme/Controls/Lists/Resources/Sheet 8.pdf)
I presume the SSE in turn lifted their plans from previous pumped-storage schems such as Cruachan.

For my scheme 70 hours at the full power rating of the pumps but actually the water will only be pumped up as and when there is surplus power available and that will depend on such factors as how windy it is.I'll take your first answer as "I don't know." :cool:

Can you tell us how you reached the following power estimate?

Accordingly, I envision it would be appropriate and useful to install the required turbine-pumps to supply up to 12 GigaWatts of electrical power to the grid for up to 50 hours before the energy store would be exhausted.
Where does the 12GW figure come from?

Following Rheghead's question, where would you place your generators? At the foot of the dam, or close to Loch Lochy?

Rheghead

16-Mar-12, 23:58

Following Rheghead's question, where would you place your generators? At the foot of the dam, or close to Loch Lochy?

I wrongfully assumed that they would be at the foot of the dam but when I put the available info into the E=mgh equation then I couldn't quite make it stack until I realised h was the height of the foot of the dam wall above Loch Lochy plus the mean height of the dam wall then it all came together as it were and Peter was spot on with his calculations.

secrets in symmetry

17-Mar-12, 00:09

Thanks Rheghead. I was too lazy to do the energy calculation myself.

I still want to know how Peter will generate his 12GW.

Peter Dow

17-Mar-12, 00:27

Dam foundations and height of the dam above the bedrock
The top of the Dow-Dam has an elevation of 780 metres by design.

http://scot.gcehosting.com/forum/media/glacialdeposit.jpg
Image also hosted here (http://postimage.org/image/4hq7u96g1/)

The lowest elevation of the current ground surface of Coire Glas along the line of the proposed dam is 463 metres and subtracting 463 from 780 is how the initial value of 317 metres for the nominal height of the dam above the existing surface used in previous diagrams was arrived at.

However, the glacial deposit of as yet unknown thickness is to be removed before building the foundations of the dam within and upon the bedrock.

Although the lowest surface elevation along the line of the dam of the bedrock too is unknown a formula relating the Height of the Dam Above the Bedrock (HDAB) to the Glacial Deposit Depth (GDD) can be easily stated.

HDAB = 317 + GDD

Examples.

If the GDD turns out to be 13 metres then the dam will be 330 metres tall.
If the GDD turns out to be 83 metres then the dam will be 400 metres tall.

http://scot.gcehosting.com/forum/media/damfoundation.jpg
Image also hosted here (http://postimage.org/image/b322et0w3/)

I propose that the height of the Dow-Dam be as tall above the bedrock as it needs to be to keep the top of the dam at an elevation of 780 metres no matter how deep the removed glacial deposit layer turns out to be.

My approach may well differ from the SSE's approach. The SSE have said that their dam will be "92 metres" high and they may stick to that without having any goal for the elevation of the top of their dam.

As the diagram indicates, I propose to secure the Dow-Dam to the bedrock by massive piles inserted and secured into shafts which would be drilled into the bedrock.

Errogie

17-Mar-12, 11:50

It might be a good idea to stop referring to the project as the "Dow-Dam" when really at this stage what we've been talking about is the Coire Glas pump storage proposal from SSE.

Have you ever been there? The overspill connection to Loch Arkaig and fluctulating levels on that loch will have an effect upon the river Arkaig and migratory fish movements into it and the logistics and environmental effects of loosing 400 million tons of material in the local landscape could be a headache. I really think you should follow up your work by taking a couple of days to explore the site so you can back up your views.

secrets in symmetry

17-Mar-12, 14:53

It might be a good idea to stop referring to the project as the "Dow-Dam" when really at this stage what we've been talking about is the Coire Glas pump storage proposal from SSE.
Let's not deny the man his moment of fame, Errogie.

Peter, you still haven't told us how you obtained your figure of 12GW electrical power delivery.

Have you ever been there? The overspill connection to Loch Arkaig and fluctulating levels on that loch will have an effect upon the river Arkaig and migratory fish movements into it and the logistics and environmental effects of loosing 400 million tons of material in the local landscape could be a headache. I really think you should follow up your work by taking a couple of days to explore the site so you can back up your views.The River Arkaig (if it still exists) could be a white water river flowing the wrong way when Peter's hydro station is generating electricity - God help the fish!

Peter Dow

17-Mar-12, 18:01

Extract from "Analysis of UK Wind Generation November 2008 to December 2010"

"PUMPED STORAGE HYDRO

...
The logistics of backing up wind energy with pumped storage hydro are such that even if there were enough suitable locations,
There are enough suitable locations and it is absurd to think there might not be. All that is required of a location is fairly steep hills with a good water supply and the British Isles is well supplied with locations which have both.

... the scale and cost of the Civil Engineering exercise to construct it would be prohibitive."
Not "prohibitive" for a competent government investing in appropriate national infrastructure projects.

The Governor of the Bank of England has not prohibited himself from printing £325 billion of "Quantitative Easing" money to give to his broke city pals who have gone bust making bad investments and who desperately wanted bailing out.

Neither have the First Lord of the Treasury David Cameron, nor the Chancellor of the Exchequer George Osborne prohibited Sir Mervyn King from printing the UK's cash to his heart's content and doing with it randomly as he pleases. On the contrary, they and Her Majesty's loyal opposition, who as the former Labour Government appointed Sir Mervyn in 2003, have simply trusted this man, Mervyn King, with the economy.

Rather our politicians have prohibited themselves from taking any grip whatsoever over the course of economic investment and instead satisfied themselves with the trappings of office and their trust and belief in Sir Mervyn.

The SNP for all its bleating about "independence" have prohibited themselves from establishing a Scottish central bank and ordering it to print as much or more new Sterling as Sir Mervyn has.

The broadcasting media and the courts have prohibited TV exposing these incompetent politicians for the chancers they are with their ill-founded trust in Sir Mervyn King.

We the people have prohibited ourselves from establishing a republic that would kick these royalist fools off the political park!

But that's OK, because King's got a knighthood from the Queen! :roll:

(Republican rant over!) :lol:

Peter Dow

17-Mar-12, 18:57

Peter,
I am the last one to want to dampen new and innovative thinking but you'll need to bear in mind the following.
I understand that the Great Glen fault is actually only one part of a very old crack in the earth's surface which runs from Bergen to Newfoundland. In our section there has been a sideways sheering action which has displaced both sides by up up to 60 miles although the geologists revise their theories at regular intervals.

This process has subjected the rocks to huge stress and we still experience minor tremors along the line (I had a 1.8 under my house a few years ago).

Wikipedia: List of earthquakes in the British Isles (http://en.wikipedia.org/wiki/List_of_earthquakes_in_the_British_Isles) says that a 6.1 on the Richter is the biggest ever recorded in the British Isles. From looking at that list that Richter 6.1 at Dogger Bank, the North Sea in 1931 looks to be about the biggest here in 1000 years.

So maybe somewhere around a 7.1 Richter would be the biggest to expect here in 10,000 years. Earthquake Facts and Statistics

(http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php)I would want to build a dam that was strong enough to survive a "biggest earthquake here in 10,000 years" event so I'd looking for a dam that can take a 7.1 on the Richter in its stride.

So really people ought to be a lot more worried about their own house falling down on them than any dam I have a say in designing and getting built.

When the Foyers pump storage scheme was completed in the early 70's they filled up the tunnel between Loch More and Loch Ness closed the exit and overnight it mysteriously emptied. The next three weeks were spent grouting cracks in the tunnel.

More recently the Glendoe hydro scheme tunnel suffered a massive collapse a few weeeks after HRH opened it and 2 years on they're still trying to repair it with a new bypass tunnel, the whole operation probably costing more than the original works and obviously a lawyer's and accountant's bunfight.
I think you are absolutely right to raise these issues. I would not be surprised to learn that there have been a number of costly mistakes made by the SSE and I am not here to vouch for the SSE's record nor to in any way suggest that they would make the correct decisions.

I am here to put forward my scheme, my plan for Coire Glas and to show how that could be done safely.

I am not here to guarantee how the SSE would do their plan. I am not saying "trust the SSE".

I am saying "trust yourselves" and your own ability to scrutinise the issues, given access to all the information and to be allowed an open debate and consideration to come to a view about both my plan and the SSE's.

I like the SSE's plan for Coire Glas because it is inspirational in concept and leads me to think of a bigger better plan. I don't like the SSE's plan because I trust the SSE to do it right given their track record or the track record of this kingdom. The SSE's Coire Glas big dam project could be another "Titanic" if left solely in the hands of the kingdom and its institutions.

It's the same if I had been around when the Titanic was being planned to be built. I would have said - "Wow, that's really inspirational - great idea to build a big ship - now how about putting some more lifeboats on board, and fixing some really bright lights on it so that the ship's pilots can see where they are going in the dark?"

So I am for the SSE's concept of a big dam in the same way as I am for the concept of a big ship. That doesn't mean I trust the SSE or that I would have trusted the White Star Line to sail the Titanic anywhere but into an iceberg.

I think the Great Glen has to be treated with respect. We had a wipeout about 7000 years ago when the the glacial plug in adjacent Glen Gloy burst and sent a huge flood east sweeping the floor of the glen. The prospect of being caught by a dam fracture en route to Fort William on the A82 fills me with some unease!
Well we need to be sure that the SSE does not build their dam on top of the loose topsoil - not just "soil" but the glacial deposit consisting of sand & gravel and loose material of all kinds - because that could get washed out and the dam could burst from underneath its foundations.

It really is essential that the superficial deposits are all removed and the foundations of the dam are built into the bedrock. This is standard practice when building anything big really so I am not expecting the SSE to be so foolish but you never do know. Best to make sure.

Peter Dow

17-Mar-12, 22:23

In the documentary 'Life after People', the Hoover Dam survives for 10,000 years. Quite encouraging then?
I just watched that programme on the internet. Interesting programme. Thanks for reminding me of it. I remember seeing the trailers for it but I don't know if I had seen the whole thing until now.

"Life After People" contains many good lessons on how not to build something to last 10,000 years and overall it is not encouraging for the standard construction methods in use today as being acceptable for any dam I am building.

There are big variations in the standard of concrete - some Roman concrete surviving to this day - lower water content and more tightly packed - but most concrete today nowhere nearly as good. So an important lesson there.

I've already mentioned here, or somewhere, that mild steel rebar is unacceptable to me but stainless steel rebar may well be good enough.

I haven't yet decided on the binder for the concrete. This will be an important decision that I don't want to rush.

Possibly for the core of the dam, asphalt concrete has good physical properties.

Wikipedia: Asphalt concrete (http://en.wikipedia.org/wiki/Asphalt_concrete)
(http://en.wikipedia.org/wiki/Asphalt_concrete)
Asphalt concrete is a composite material commonly used in construction projects such as road surfaces, airports and parking lots. It consists of asphalt (used as a binder) and mineral aggregate mixed together, then laid down in layers and compacted. It is also increasingly used as the core for embankment dams.

So maybe asphalt concrete for the dam core but for the surface concrete that will endure the weathering I am thinking I'd like something better - maybe a silicone-based cement to make the concrete, for the surface layers at least.

If could buy it in bulk and a cheap enough price then maybe silicone cement for the whole dam's concrete including the core but it would a huge amount of concrete so probably savings will have to be made and exotic materials used where they do most good, such as on the surface.

I noticed that they had a Scottish engineer contributing to that programme, Gordon Masterton, who seemed to know his engineering. Not bad, for a royalist; I see he has now got an OBE which as a republican I can't approve of but I'd offer him a job anyway, just as soon as I get that £20 billion from the government to build this.

I was not encouraged by the way the molluscs blocked the Hoover Dam's cooling pipes so quickly, causing it to fail. I would be looking for some kind of anti-fouling on and in the pipes in my pumped storage dam, such as copper or copper-alloy pipes or plating, maybe?

Rheghead

17-Mar-12, 22:54

Peter Dow

17-Mar-12, 23:04

I'll take your first answer as "I don't know." :cool:
I don't need to design every last aspect of the scheme on my own right now. All important details such as number of turbines, size of head and tail races (that's the pipe or water tunnels to the turbine pumps etc) would be considered at the right time.

Can you tell us how you reached the following power estimate?

Where does the 12GW figure come from?
First I worked out what the maximum size of energy store could be built at the Coire Glas site and that came out around 600 GigaWatt.Hours or 20 times what the SSE plan of 30 GigaWatt.Hours. The SSE plan 0.6 GigaWatts worth of turbines which would use up their energy store in 50 hours so I simply considered also having enough power to deliver the energy in 50 hours which means I would also need 20 times their SSE's 0.6 GW power which comes out as 12 GW.

The turbine power is simply a selection and purchase issue.

This power flow map (figure are MegaWatts I believe)

http://www.nationalgrid.com/uk/sys_09/chap4/images/fig4-1.gif
shows that 12 GW is more than plenty for Scotland's needs. The total generating capacity in Scotland now is 10 GW and that leaves 2 GW (at least) spare. It would be handy to have extra bays for additional turbines because some will be down for maintenance and you probably would like to have a research bay to work on experimental turbines to advance the state of the art so I really don't think 12 GW is excessive but then neither is all that power the answer when you run out of energy.

So I think additional energy, having a larger reservoir would be more useful than additional power but I think I have squeezed as much energy out of Coire Glas as I can. Possibly with more work maybe 700GW.Hours or even 800GW.Hours might be possible but that's just a hunch.

To get a much bigger energy store for Scotland, to cover for a wider range of weather conditions becalming wind farms it will be necessary to use a second location, another hydro dam scheme altogether, and then once that is up and running, split the turbines up, have 6 GW at Coire Glas and 6 GW at the other site.

Following Rheghead's question, where would you place your generators? At the foot of the dam, or close to Loch Lochy?
Well he has since answered his own question though I don't know why it would be such a mystery.

This diagram is from the Wikipedia article on pumped storage hydroelectricity (http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity). Come on guys. This is the easy stuff.

http://upload.wikimedia.org/wikipedia/commons/9/9a/Pumpstor_racoon_mtn.jpg

ywindythesecond

17-Mar-12, 23:55

[QUOTE=Peter Dow;936988]There are enough suitable locations and it is absurd to think there might not be. All that is required of a location is fairly steep hills with a good water supply and the British Isles is well supplied with locations which have both.

David J C MacKay doesn't think so:

"By building more pumped storage systems, it looks as if we could increaseour maximum energy store from 30GWh to 100GWh or perhaps400GWh. Achieving the full 1200GWh that we were hoping for lookstough, however."
Page 194 in the hard copy, towards the end of Section 26

Peter Dow

18-Mar-12, 00:15

It might be a good idea to stop referring to the project as the "Dow-Dam" when really at this stage what we've been talking about is the Coire Glas pump storage proposal from SSE.
Well I thought I had made it clear that I was proposing a much bigger, 20 times bigger scheme than the SSE's, to be a government-funded infrastructure project.

I thought I had made it clear that I was proposing a much bigger dam, the "Dow-Dam" or the "Coire Glas 600GigaWatt-Hour" dam. This dam would be 3.44 times higher than the SSE's dam and 2.27 times longer. It's a different design of a dam for the same site.

If you want to just worry about the SSE dam and ignore my proposal then go ahead. Maybe though in reading the details of what I have to say about building dams in general this might inform your concerns about the SSE dam.

But I am not convinced that the SSE's 30 GW.Hr proposal for Coire Glas, even with their proposed scheme for Balmaccan is enough to meet the strategic goal of a future of 100% renewable power. To my mind, the SSE dam doesn't address the real future needs. It is a small, cautious step in the right direction but now is the time is for big, bold steps, in my opinion.

The modest SSE scheme for Coire Glas is only what they think they, the SSE, as a company can afford in the next few years.

Well OK but the government has a much bigger spending power than the SSE will ever have. As I have mentioned, the Bank of England has printed £325 billion of new money which I think would be better spent on renewable energy projects than bailing out Sir Mervyn's broke pals in the city.

I see the need for national strategic economic investment and that's what I am talking about.

Have you ever been there?
Not recently, no. When I was younger my mother took my brother and I around a lot of Scotland so no doubt I passed through the Great Glen a number of times but I don't remember ever scouting out Coire Glas, Loch Lochy or Loch Arkaig for any particular reason. I do remember a visit to a hydro-electric scheme and seeing a corrie in my time but I can't remember which ones.

The overspill connection to Loch Arkaig and fluctulating levels on that loch will have an effect upon the river Arkaig and migratory fish movements into it
Ah, you are talking about my scheme! The SSE don't plan to have an overspill water channel between Loch Lochy and Loch Arkaig, at all. That's my idea which is only needed because I have so much more water to cope with. The SSE don't need to use Loch Arkaig for their much smaller volume of water. The main effect of the new water channel between the lochs is that any old fish will be able to get from Loch Lochy to Loch Arkaig whereas now it is a more difficult up-river swim to go from Loch Lochy to Loch Arkaig and I guess only the fitter fish can do that now?

and the logistics and environmental effects of loosing 400 million tons of material in the local landscape could be a headache.
Well logistics is an issue for sure. Whilst I hope to use British suppliers I am not sure if JCB or any British construction company have anything as big as this T282C truck from the Swiss company Liebherr.

http://bloximages.chicago2.vip.townnews.com/trib.com/content/tncms/assets/v3/editorial/4/74/4746d685-7543-52db-9254-b396441a8003/4e605d2d3bb49.image.jpg

The Liebherr T282C has a paylod of 363 tonnes. Now with 100 of those trucks doing 100 journeys a day for 100 days, most of that 400 million tonnes of rock could be moved. If that's too optimisitic then maybe more trucks or more days would be needed.

Now if JCB or another British company can match that performance and provide a logistical solution then OK I am happy to buy British.

But even that amount of rock can be put into a landfill somewhere not too far away, covered over, landscaped and you'd never know it was there.

I really think you should follow up your work by taking a couple of days to explore the site so you can back up your views.
Well maybe I will just as soon as that £20 billion from the government is on the table.

Actually though what with Google Earth and Google street view, I can go for a virtual look around the area from here at home and I have already done so a few times. No doubt there is more to see and I look forward to seeing it!

ywindythesecond

18-Mar-12, 00:25

secrets in symmetry

18-Mar-12, 01:22

I don't need to design every last aspect of the scheme on my own right now. All important details such as number of turbines, size of head and tail races (that's the pipe or water tunnels to the turbine pumps etc) would be considered at the right time.

First I worked out what the maximum size of energy store could be built at the Coire Glas site and that came out around 600 GigaWatt.Hours or 20 times what the SSE plan of 30 GigaWatt.Hours. The SSE plan 0.6 GigaWatts worth of turbines which would use up their energy store in 50 hours so I simply considered also having enough power to deliver the energy in 50 hours which means I would also need 20 times their SSE's 0.6 GW power which comes out as 12 GW.

The turbine power is simply a selection and purchase issue.Thanks, that's all I wanted to know. You could have said you just scaled up the SSE design, but that wouldn't have helped because I didn't know what SSE already had planned lol.

This power flow map (figure are MegaWatts I believe) shows that 12 GW is more than plenty for Scotland's needs. The total generating capacity in Scotland now is 10 GW and that leaves 2 GW (at least) spare. It would be handy to have extra bays for additional turbines because some will be down for maintenance and you probably would like to have a research bay to work on experimental turbines to advance the state of the art so I really don't think 12 GW is excessive but then neither is all that power the answer when you run out of energy.

So I think additional energy, having a larger reservoir would be more useful than additional power but I think I have squeezed as much energy out of Coire Glas as I can. Possibly with more work maybe 700GW.Hours or even 800GW.Hours might be possible but that's just a hunch.

To get a much bigger energy store for Scotland, to cover for a wider range of weather conditions becalming wind farms it will be necessary to use a second location, another hydro dam scheme altogether, and then once that is up and running, split the turbines up, have 6 GW at Coire Glas and 6 GW at the other site.
Ok, I understand your thinking now.

For various reasons, I think a number of smaller pumped storage stations would be better than a single gigantic one. Do you know of other locations that could provide a similar setup?

I'm more optimistic that such a system can be built in Scotland than I was before I started reading this thread. I'm hoping that David Mackay has seriously underestimated the country's capacity for pumped storage systems.

Rheghead

18-Mar-12, 02:19

The "exceptional lull" identified in 2007 in Ireland has been proven to be quite a normal event in UK since November 2008. Similar or greater(?) lulls occured in UK in Dec 2008. Jan, Feb, June, July (extensive), August, September, October, November, December (extensive) 2009. Jan, Feb (extensive), March (extensive), April, May (extensive), June, August (extensive), and December 2010.
See graphs at http://www.jmt.org/assets/pdf/Report_Analysis UK Wind_SYoung.pdf

Since we've already debunked that report extensively on this forum then I'd rather not thank you. However, since you were keen to quote Dr David JC Mackay in reply to Peter Dow then I will refer him also in that he thinks a 5 day lull of wind is something that should be covered by a pumped storage facility. ;)

Rheghead

18-Mar-12, 11:34

I think the Dow-dam is a great idea and I'm looking forward to seeing the Queen laying the foundation stone of the dam wall or knighting the person who first conceived the idea.

ywindythesecond

18-Mar-12, 22:52

http://forum.caithness.org/images/misc/quote_icon.png Originally Posted by ywindythesecond http://forum.caithness.org/images/buttons/viewpost-right.png (http://forum.caithness.org/showthread.php?p=937097#post937097)
The "exceptional lull" identified in 2007 in Ireland has been proven to be quite a normal event in UK since November 2008. Similar or greater(?) lulls occured in UK in Dec 2008. Jan, Feb, June, July (extensive), August, September, October, November, December (extensive) 2009. Jan, Feb (extensive), March (extensive), April, May (extensive), June, August (extensive), and December 2010.
See graphs at http://www.jmt.org/assets/pdf/Report...ind_SYoung.pdf (http://www.jmt.org/assets/pdf/Report_Analysis%20UK%20Wind_SYoung.pdf)

Since we've already debunked that report extensively on this forum then I'd rather not thank you. However, since you were keen to quote Dr David JC Mackay in reply to Peter Dow then I will refer him also in that he thinks a 5 day lull of wind is something that should be covered by a pumped storage facility. ;)

Which of the lulls I referred to did not happen because you "debunked" the report? Does a "Reggy debunking" change history? Does it eliminate the records produced by National grid which are available to anyone with an internet connection? Why don't you just address the evidence before you and use your not inconsiderable intellect in a more useful manner than trolling?

Rheghead

18-Mar-12, 23:25

Ywindy, this thread is about pumped storage and not about pushing your bias against wind farms despite your efforts to do otherwise using debunked rubbish.

ywindythesecond

19-Mar-12, 01:47

Ywindy, this thread is about pumped storage and not about pushing your bias against wind farms despite your efforts to do otherwise using debunked rubbish.
As I understand it, this thread is about how pumped storage hydro can back up wind generation. I am pointing out how much pumped storage is required to back up wind generation when wind is absent, and referring to data sourced from National Grid, and David J C Mackay's excellent book http://www.withouthotair.com/ . I am sure that anyone following this thread will be intrigued to learn why you choose not to address the generation issues arising from proven protracted periods of low wind. Please enlighten them.

Rheghead

19-Mar-12, 02:07

I am sure that anyone following this thread will be intrigued to learn why you choose not to address the generation issues arising from proven protracted periods of low wind. Please enlighten them.

I am not addressing it because the quality of the data is extremely poor as it cannot possibly have any relevance when factored up to tackle problems of variability on the scale which the Dow-dam is designed. Bad data in, bad data out.

ywindythesecond

19-Mar-12, 09:24

I am not addressing it because the quality of the data is extremely poor as it cannot possibly have any relevance when factored up to tackle problems of variability on the scale which the Dow-dam is designed. Bad data in, bad data out.

The strongest condemnation of my report from the established wind industry is found here http://www.scottishrenewables.com/news/statement-john-muir-trust-analysis-UK-wind-power-/ It is worth noting that the Garrad Hassan report referred to has never been published presumably because it also confirms that the wind industry claim of 30% average wind output was wrong. The second strongest condemnation is found here on Caithness.org and comes from Reggy "because he says so".
Reggy, you might get some support for your views if you put forward a reasoned argument and not just pout and stamp your foot!

Rheghead

19-Mar-12, 09:55

Well it certainly looking like you're the one who is stamping the foot and doing the personal insults.

EOS

19-Mar-12, 11:04

Peter Dow a very interesting character!!!!! check him out on Google.

Peter Dow

19-Mar-12, 17:04

http://www.youtube.com/watch?v=asUa1PFix1A

Video (http://youtu.be/asUa1PFix1A) which illustrates the principle of using wind turbines and pumped storage hydro dam schemes together.

Oddquine

21-Mar-12, 01:18

Peter Dow a very interesting character!!!!! check him out on Google.

You think? I'm on a few forums where he posts exactly the same stuff as he does here. In fact I was horrified to see his name when I wandered into General as opposed to sticking mostly to Genealogy.

He has always struck me as an individual with an inflated sense of his own adequacy. Who elected him the Scottish National Standard Bearer anyway?

John Little

21-Mar-12, 09:23

Who elected him the Scottish National Standard Bearer anyway?

It appears that leadership qualities suffice;

http://scot.cyberhost.me/functionsofbearerset.htm

Corrie 3

21-Mar-12, 10:05

It appears that leadership qualities suffice;

http://scot.cyberhost.me/functionsofbearerset.htm
And the ability to produce superior offspring John, dont forget that!!!

(sounds like someone familiar, small chap with a little moustache, born in Austria and then moved to Germany. Cant think of his name right now)!!!

C3.....................:eek::eek:

golach

21-Mar-12, 10:07

And the ability to produce superiour offspring John, dont forget that!!!

(sounds like someone familiar, small chap with a little moustache, born in Austria and then moved to Germany. Cant think of his name right now)!!!C3.....................:eek::eek:
Adolph Mugabe Salmond?? [lol]

Oddquine

22-Mar-12, 02:53

It appears that leadership qualities suffice;

http://scot.cyberhost.me/functionsofbearerset.htm

Self praise is no praise, imo.

John Little

22-Mar-12, 08:28

Your o is correct imo.

My tongue is firmly in my cheek.

Phill

22-Mar-12, 09:34

The Dow is a leg end!!

Deal with it inferior peeps!

Peter Dow

22-Mar-12, 22:42

I think your dam should be capable of producing power over a 5 day period which is equivalent to an exceptional lull in wind performance (see Ch 6, p189. Sustainable Energy without the hot air). If the energy capacity of your dam is 600GWh then I think 5GW would be a more suitable output.
5GW would be very useful certainly and could serve Scottish domestic demand especially when you add in conventional hydroelectric power.

I do want more power to match current Scottish peak generating (8.5GW, which includes some exported power) current capacity (10GW) and even more power available would be nice to look to a future when people buy more renewable electricity for their heat requirements (which many now get from gas / oil / coal etc) but more power would be most useful with more energy stored.

If you have more power available then you don't have to use it all the time. If the weather predicts a prolonged lull in wind, then you only use 5GW. If a one or two day lull is predicted then you could afford to use more power.

Sure I would rather have another site with another 600GW.Hrs and split my 12GW into 2 x 6GW. I say "6GW" rather than 5GW because you ought to have a bit more maximum capacity than you use at peak because there will be a need for maintenance on some turbine-pumps taking some turbine-pump bays off line.

12GW is like a "wish list" selection for the best possible site at Coire Glas where cost is no problem. In reality cost is always an issue and if I had a fixed budget and another site to build another 600GW.Hr store at, I would split the 12GW into 2 x 6GW with 6GW at each site.

Peter Dow

22-Mar-12, 23:26

There are enough suitable locations and it is absurd to think there might not be. All that is required of a location is fairly steep hills with a good water supply and the British Isles is well supplied with locations which have both.

David J C MacKay doesn't think so:

"By building more pumped storage systems, it looks as if we could increaseour maximum energy store from 30GWh to 100GWh or perhaps400GWh. Achieving the full 1200GWh that we were hoping for lookstough, however."
Page 194 in the hard copy, towards the end of Section 26
My plan offers 600GW.Hrs and what's tough about it is the cost - order of magnitude £20 billion - which makes it very tough for an electricity or power station company like SSE or Scottish power to build 600 GW.Hrs and even tougher to build 1200GW.Hrs.

However, when the going gets tough the tough get going and there's none tougher than governments. Building these large energy stores is a economic infrastructure project which should be funded by governments.

I am not sure whether HMGs are tough or just plain dumb when they apparently can afford to let Sir Mervyn King, Governor of the Bank of England, print an exceedingly tough £325 billion as "Quantitative Easing" to bail out his city pals who went broke making bad bets on the casino money markets?

As to exactly why Sir Mervyn appears to be so tough as to print £325 billion of new Sterling and none of the politicians bat an eye, or manage to murmur a question or two about it can only be down to them being dumb royalists.

Peter Dow

23-Mar-12, 00:05

Thanks, that's all I wanted to know. You could have said you just scaled up the SSE design, but that wouldn't have helped because I didn't know what SSE already had planned lol.

Ok, I understand your thinking now.

For various reasons, I think a number of smaller pumped storage stations would be better than a single gigantic one. Do you know of other locations that could provide a similar setup?
There seem to be a number of sites with the appropriate geography and I think the west coast of Scotland is best.

I am thinking that using a sea loch or the coastal sea as the lower reservoir simplifies matters.

You can see all the extra water flow control works around Loch Lochy I have had to propose to cope with the amount of water a 600GW.Hrs store uses.

I have been scouting out for possible sites using google maps and I have marked a few out for further investigation when I get the time.

I'm more optimistic that such a system can be built in Scotland than I was before I started reading this thread. I'm hoping that David Mackay has seriously underestimated the country's capacity for pumped storage systems.
I think he is estimating the capacity of electricity companies who can't afford to build such massive reservoirs. I don't think he has approached this from the point of view that it could be and should be a government funded project. So he was estimating what electricity consumers could afford in the short term, rather than estimating what the country could afford to build.

However, David MacKay covered a lot of ground in his book. It is not surprising that he has not had time to go into massive detail on all points. I am concentrating on pumped storage and wind so I have had time to get more of the details correct on those perhaps.

For example, David in his book states that wind farm power production is independent of rotor diameter - which is simply incorrect and proved so by the trend to increasingly greater wind turbine size.

The better equation for a wind farm's power output than what David has is

"Power and energy is proportional to (the square root of the wind farm area) times the rotor diameter".
You heard it here first! :cool:

If you are nice to me I will even show you the derivation, or Dow-credit-points for anyone who can derive it on their own.

Peter Dow

23-Mar-12, 20:42

I think the Dow-dam is a great idea
Thank you.

and I'm looking forward to seeing the Queen laying the foundation stone of the dam wall or knighting the person who first conceived the idea.
Well I am a republican and ferociously so. If I have any say in it, the royals will be banned from the Coire Glas site at all times, before, during and after construction.

So it goes without saying that I won't accept any knighthood nor any other honour from them.

Nor would I accept membership of the Royal Society or any royalist institution whatsoever.

I just don't value being "honoured" by people who have violated the honour of scientists and intellectuals by accepting the existence of any kingdom and a non-deserved special role for a royal family.

Likewise I despise politicians who swear oaths of allegiance to the Queen and call themselves in the House of Commons "the honourable member ..." There is nothing honourable about betraying the principles of democracy.

You have struck a raw nerve there Rheghead though you didn't strike me as the trolling type but I sense that you know I am a republican and are typing that "tongue in cheek" or as a wind up. Please don't. It is not worthy of you.

To me those who accept the role of the monarchy are the same scum as Thomas Hamilton who shot the Dunblane kids dead. Your Queen's police gave Hamilton his firearms certificate and I cannot forgive Hamilton, the police, the Queen or anyone who apes false sorrow for a crime of incompetence of the sort that incompetent royalists make all the time.

Stupid people in charge is not logical, as Spock might have said. I'd go further and say it is an evil state of affairs.

secrets in symmetry

24-Mar-12, 18:53

There seem to be a number of sites with the appropriate geography and I think the west coast of Scotland is best.

I am thinking that using a sea loch or the coastal sea as the lower reservoir simplifies matters.

You can see all the extra water flow control works around Loch Lochy I have had to propose to cope with the amount of water a 600GW.Hrs store uses.

I have been scouting out for possible sites using google maps and I have marked a few out for further investigation when I get the time.A Sea loch (or the sea itself) would seriously reduce the problem of rapidly changing water levels in the lower reservoir, but it would introduce the problem of dealing with salt water - both in the pipes and generators, and in the upper reservoir.

I think he is estimating the capacity of electricity companies who can't afford to build such massive reservoirs. I don't think he has approached this from the point of view that it could be and should be a government funded project. So he was estimating what electricity consumers could afford in the short term, rather than estimating what the country could afford to build.

However, David MacKay covered a lot of ground in his book. It is not surprising that he has not had time to go into massive detail on all points. I am concentrating on pumped storage and wind so I have had time to get more of the details correct on those perhaps.

For example, David in his book states that wind farm power production is independent of rotor diameter - which is simply incorrect and proved so by the trend to increasingly greater wind turbine size.

The better equation for a wind farm's power output than what David has is

"Power and energy is proportional to (the square root of the wind farm area) times the rotor diameter".
You heard it here first! :cool:

If you are nice to me I will even show you the derivation, or Dow-credit-points for anyone who can derive it on their own.It's years since I read David Mackay's book, but my memory suggests that his claim was based on the lack of sufficient locations with the necessary geography/geometry for massive pumped storage stations. I don't think it was a money thing. This is easy to sort out - read his book!

I don't know how well he knows Scotland. Despite being a Mackay, he's not from Caithness, and he's not even Scottish as far as I know. I met him a long time ago and I'm pretty sure he's from way south of the border.

Wind farm output depends on a lot of variables. You can't change rotor diameter without affecting other factors such as the spacing between windmills.

Neverthess, I'll respond positively to your offer - please show us your derivation.

Peter Dow

25-Mar-12, 07:00

Wind farm output depends on a lot of variables. You can't change rotor diameter without affecting other factors such as the spacing between windmills.

Neverthess, I'll respond positively to your offer - please show us your derivation.
Coming right up! :D

Derivation

Assume various simplifications like all turbine rotors are the same size and height, flat ground and a rotationally symmetrical wind turbine formation so that it doesn't matter what direction the wind is coming from.

Consider that an efficient wind farm will have taken a significant proportion of the theoretically usable power (at most the Betz Limit, 59.3%, apparently, but anyway assume a certain percent) of all the wind flowing at rotor height out by the time the wind passes the last turbine.

So assume the wind farm is efficient or at least that the power extracted is proportional to the energy of all the wind flowing through the wind farm at rotor height.

This defines a horizontal layer of wind which passes through the wind farm of depth the same as the rotor diameter. The width of this layer which flows through the wind farm is simply the width of the wind farm which is proportional to the square root of the wind farm area.

Wind farm turbine formations

Therefore the width or diameter of a rotationally symmetrical wind farm is a critically important factor and arranging the formation of wind turbines to maximise the diameter of the wind farm is important.

Consider two different rotationally symmetrical wind turbine formations, I have called the "Ring formation" and the "Compact formation".

Let n be the number of wind turbines in the wind farm
Let s be the spacing between the wind turbines

Ring formation

http://scot.tk/forum/media/windfarmcircular.jpg

http://s18.postimage.org/h345i6t8l/windfarmcircular.jpg (http://postimage.org/image/h345i6t8l/)
Larger image also hosted here (http://postimage.org/image/h345i6t8l/)

The circumference of the ring formation is simply n times s.

Circumference = n x s

The diameter of the ring formation is simply n times s divided by PI.

Diameter = n x s / PI

Peter Dow

25-Mar-12, 07:03

Compact formation

http://scot.tk/forum/media/windfarmcompact.jpg

http://s16.postimage.org/mqvr13vjl/windfarmcompact.jpg (http://postimage.org/image/mqvr13vjl/)
Larger image also hosted here (http://postimage.org/image/mqvr13vjl/)

The area of the compact formation, for large n, is n times s squared. This is slightly too big an area for small n.

Area = n x s^2 (for large n)

The diameter of the compact formation, for large n, is 2 times s times the square root of n divided by PI. This is slightly too big a diameter for small n.

Diameter = 2 x s x SQRT(n/PI)

This is easily corrected for small n greater than 3 by adding a "compact area trim constant" (CATC) (which is a negative value so really it is a subtraction) to the s-multiplier factor.

The CATC is 4 divided by PI minus 2 times the square root of 4 divided by PI.

CATC = 4/PI - 2 x SQRT(4/PI) = - 0.9835

This CATC correction was selected to ensure that the compact formation diameter equation for n=4 evaluates to the same value as does the ring formation equation for n = 4, that being the largest n for which the ring and compact formations are indistinguishable.

The CATC works out to be minus 0.9835 which gives

Diameter = s x ( 2 x SQRT(n/PI) - 0.9835) (for n > 3)

Peter Dow

25-Mar-12, 07:04

Ratio of diameters

http://scot.tk/forum/media/windfarmratio.jpg

http://s18.postimage.org/f2dlxcx39/windfarmratio.jpg (http://postimage.org/image/f2dlxcx39/)
Larger image also hosted here (http://postimage.org/image/f2dlxcx39/)

It is of interest to compare the two formations of wind farm for the same n and s.

The diameter of the ring formation is larger by the ratio of diameter formulas in which the spacing s drops out.

Ring formation diameter : Compact formation diameter

n/PI : 2 x SQRT (n/PI) - 0.9835

This ratio can be evaluated for any n > 3 and here are some ratios with the compact value of the ratio normalised to 100% so that the ring value of the ratio will give the ring formation diameter as a percentage of the equivalent compact formation diameter.

Here are some examples,

n = 4, 100 : 100
n = 10, 123 : 100
n = 18, 151 : 100
n = 40, 207 : 100
n =100, 309 : 100
n =180, 405 : 100
n =300, 514 : 100
n =500, 656 : 100

As we can see that for big wind farms, with more turbines, the ratio of diameters increases.

Since the Dow equation for the power and energy of a wind farm is proportional to the diameter of the wind farm then it predicts that the power and energy of the ring formation wind farms will be increased compared to the compact formation wind farms by the same ratio.

In other words, the Dow equation predicts, for example, that a 100 turbine wind farm in the ring formation generates 3 times more power and energy than they would in the compact formation, assuming the spacing is the same in each case.

Practical application when designing a wind farm

My recommendation would be to prefer to deploy wind turbines in a wind farm in the ring formation in preference to the compact formation all other things being equal.

The compact formation can be improved up to the performance of a ring formation by increasing the turbine spacing so that the circumference is as big as the ring but then if a greater turbine spacing is permitted then the ring formation may be allowed to get proportionally bigger as well keeping its advantage, assuming more area for a larger wind farm is available.

The ring formation may be best if there is a large obstacle which can be encircled by the ring, such as a town or loch where it would not be possible or cost effective to build turbines in the middle of it and so a compact formation with larger spacing may not be possible there.

Where it is not possible to install a complete ring formation then a partial ring formation shaped as an arc of a circle would do well also.

octane

25-Mar-12, 12:40

Have you put your plan direct to Alex Salmond? I don't mean his minions, I mean direct!!

It's so refreshing to see such idea's on here instead of those who are pretend/wannabee scientists and think they know everything.

Ben Cruachan has served well, a bigger one would be fantastic!!

C3.....................:)

Me and the o/h went to Cruachan power station on Friday there, never heard of the place until passing by so went to Oban then on the way back we popped in for a tour. It was only a 30min tour and I found it quite interesting about the history of the place.

http://www.visitcruachan.co.uk/

Rheghead

29-Mar-12, 19:20

The strongest condemnation of my report from the established wind industry is found here http://www.scottishrenewables.com/news/statement-john-muir-trust-analysis-UK-wind-power-/ It is worth noting that the Garrad Hassan report referred to has never been published presumably because it also confirms that the wind industry claim of 30% average wind output was wrong. The second strongest condemnation is found here on Caithness.org and comes from Reggy "because he says so".
Reggy, you might get some support for your views if you put forward a reasoned argument and not just pout and stamp your foot!

Again you are completely disingenuous of the truth on all counts.

Your report has been also comprehensively trashed here:- http://fullfact.org/factchecks/wind_turbines_performance_capacity_muir_trust_expr ess_daily_mail-2646

Fullfact is a non-partisan organisation that strives for accuracy in public debate and it found your report wanting on several points.

issues around measuring the installed capacity and grid infrastructure limitations make it difficult to measure metered wind turbine performance with certainty.

the report can only be seen to reflect the performance of wind farms mostly situated onshore in Scotland.

The 2010 Energy statistics also note that 2010 saw onshore wind speeds below the ten year wind speed average; explaining the lower 2010 figures found by the Stuart Young report.

The report was looking solely at wind power that is 'visible' and metered by the national grid, which accounts for around half of total UK wind power generation. Offshore wind farms and some onshore farms that are connected onto the distribution network are not metered...{}...This geographical limitation means that conclusions on the performance and variability of wind generation cannot be generalised across the UK. Variability at a UK wide level would be 'smoothed' by the wider geographical spread of all wind farms.

new turbines may also come online before they are included in the total capacity figure. These differences between actual and stated capacity will distort calculated wind performance to appear better or worse than reality.

Ywindy said
It is worth noting that the Garrad Hassan report referred to has never been published presumably because it also confirms that the wind industry claim of 30% average wind output was wrong.

However, that is proved wrong by Fullfact.

The yearly average load factor between 2005-2009 was 29.2% by averaging the load factors over that range, if you are going to squabble over 0.8% then you got me but only until offshore overtakes onshore as it has an average load factor well in excess of 30%.

Peter Dow

29-Mar-12, 22:30

Reservoir bed drain

The high pressure of water which is deeper than 100 metres has the potential to induce seismic activity or earthquakes in susceptible rock in which a new reservoir has been constructed.

Wikipedia: Induced seismicity - Causes - Reservoirs. (http://en.wikipedia.org/wiki/Induced_seismicity)

The mass of water in a reservoir alters the pressure in the rock below and through fissures in the rocks, lubricates the fault, which can trigger earthquakes.
...
Unfortunately, understanding of reservoir induced seismic activity is very limited. However, it has been noted that seismicity appears to occur on dams with heights larger than 100 meters. The extra water pressure created by vast reservoirs is the most accepted explanation for the seismic activity.

Coire Glas/SSE/92 m

Hopefully, reservoir induced seismicity was an issue considered by the SSE when selecting Coire Glas for their hydro dam project.

I am speculating that this issue may be why the SSE have limited their dam to a height and their reservoir to a depth of 92 metres?

I would note however that the pressure in the head race tunnels which supply water from the reservoir to the turbines would be proportional to their depth below the surface of the reservoir and this could be as much as 500 metres deep, so there would seem to be some potential for water to penetrate the bed rock from the high pressure water tunnels and induce seismic activity even in the SSE case.

This is an issue which ought to have been addressed in the many previous pumped-storage hydro scheme projects, most of which seem to have a difference in head of more than 100 metres.

Given that "understanding ... is very limited" according to Wikipedia, though, I do wonder if the reservoir induced seismicity issue has not always been properly addressed in all previous dam and reservoir construction schemes where the great depth of water and susceptible geology ought to make it a relevant concern?

Coire Glas/Dow/317+m

I am proposing measures to counter the reservoir induced seismicity effect in the case that the geology of Coire Glas is susceptible to it and in the general case.

I propose the construction of a large reservoir surface drain to cover the whole reservoir bed and the reservoir sides too to try to stop the penetration of water under high pressure into fractures in the bedrock and so thereby stop this high pressure water from widening and extending bedrock fractures.

To illustrate my "reservoir bed drain" concept, I have drawn a diagram comparing the usual no drain on the left, with my proposed reservoir bed drain on the right.

http://scot.tk/forum/media/reservoirbeddrain.jpg

http://s14.postimage.org/u0am3dokt/reservoirbeddrain.jpg (http://postimage.org/image/u0am3dokt/)
Image also hosted here. (http://postimage.org/image/u0am3dokt/)

So my idea is that the top layer of the bed drain is as impermeable as practical, using perhaps a layer of reinforced asphalt concrete.

In engineering practice I believe that impermeable reservoir bed layers have used clay or clay with asphalt or even rubberised asphalt mixed with sand.

My basic idea is to construct an impermeable layer and to use whatever material is best for that.

Then working downwards, the permeable drain layers are increasingly bigger loose particles, with sand at the 2nd top then beneath that grit, then gravel, then small stones and finally below all those a layer of large stones.

The higher layers support the top impermeable layer which is under high pressure from the reservoir water and the lower permeable layers provide many small channels for any (hopefully tiny amounts of) water which forces its way through the supposedly impermeable top layer to drain down the slope of the reservoir bed to the base of the dam and then out under the dam through drain-pipes built into the base of the dam.

The bottom layer is another impermeable layer to try to make doubly sure that the relatively low pressure water that gets into the drain will find its way out through the dam drain pipes by following the course of the drain.

These kinds of layers of different sized loose particles have previously been used to make simple narrow drains and impermeable layers have been added to reservoir beds before now but whether professional dam engineers have ever covered the entire reservoir bed and sides with one large drain I don't know. If not, this could be named the "Dow drain" solution to reservoir induced seismicity!

Why not add a simple impermeable layer to the reservoir bed?

I think the additional complexity and expense of a bed drain (and drains for the sides too) is better than simply adding an impermeable layer.

Consider the fault condition of the two possible solutions.

If a simple impermeable layer fails, if it cracks or ruptures or disintegrates under the pressure changes, how would anyone know? It may look fine but be leaking high pressure water into the bedrock and inducing seismicity which OK the engineers would notice any earthquakes but so would everyone else, the earthquakes could cause damage or loss of life and it could lead to a loss of confidence in the project and in the engineers who built it. They could go to jail!

If the top impermeable layer of the bed drain fails then there would be some water pouring out of the drainpipes through the base of the dam when at most it should only be a tiny trickle of water. So the engineers would know there was a problem with the bed drain and they'd know to drain the reservoir and fix or replace the top supposedly "impermeable" layer, fix the bed drain so that it operated as it should.

So failure with the bed drain is noticed right away and it is not a catastrophic failure. Whereas failure with the simple impermeable layer may not be noticed until a catastrophic earthquake happens.

So this is why I think the bed drain is worth the extra complexity and expense. It is a more fault tolerant engineering solution.