New Large Scottish Pumped Storage Hydroelectric Reservoirs and Dams

I am not hyping pumped-storage by saying planning authorities have a central role in bringing about the implementation of a technology that the electricity companies are not now considering using to supply power.

I've not written "Planning authorities should make things easy for individuals or companies to put a windmill on their roof and pump water up to a water tower in their back garden" which seems to be the approach of that Scottish government document alexa first quoted, asking planning authorities to "focus" and "consider" facilitating hydrogen storage and fuel cells when that is something that frankly the electricity companies themselves are not considering as of now because the technology is not cost effective.

If one day, if ever hydrogen storage and fuel cell technology develops that far, if and when hydrogen storage and fuel cells are cheaper options for energy storage then the electricity companies themselves will start using those technologies on their own premises and there won't need to be any need for pushing from government trying to suggest planning authorities can make a difference to the way energy is stored.

Well the government shouldn't pretend that hydrogen storage and fuel cells are better, not where there's a mains supply to the national grid.

Yes but the Bank of England is giving away more tax-payer money, some £300 billion in "quantitative easing" and goodness knows whose pocket that's going into.

Renewable energy is an expensive investment, but it is actually an investment - it does actually pay back whereas we are sure the bankers are making money from Q.E. but of not much else.

Well look here, my 600+ GigaWatt-hour version of Coire Glas pumped-storage hydro dam scheme needs more like a 12 GigaWatt power line for its turbine-pumps to store and release power to Scotland and further away.

But this "only carry a gigawatt" of which you speak is not going to cut it I'm afraid.

No if you don't invest in storage, and that's what this whole article is about, so I'm glad you've finally got on-topic, if you don't invest in storage then you get deficits of renewable energy when the wind is calm and it is deficits which are the problem.

What?

I am not saying the world is at risk but not "saving the world" if it is at risk is going to cost you the world, never mind your fortune.

The bigger question is "Why does the Queen's government of Scotland get away with calling itself 'the Scottish government'?" but let's leave that aside for now.

I am the original poster in this topic so never mind what Salmond et al are up to. I'm promoting pumped storage hydro dam schemes for the Scottish economy here, not them.

Energy does come nearly free or at very low cost once you invest in enough renewable energy systems and have them installed and plugged into the grid, all you need to do to maintain energy supply is just oil and replace the bearings on the generators and pumps now and then and fix the overhead cables when a gale blows it down and that kind of routine maintenance.

If our power is cheap and if we have some left over then we can sell it. We can also host industries which increase their competitiveness when they pay less for power. Fortunes are to be had, laddie.

 

No wind generators are limited life, the wind farms built in America in the 80s are mostly derelict now.

What I'm saying is that the French use nuclear and can produce electricity for around 2.3 p per kWh, including decommissioning and the Channel is only 20 miles wide. An onshore wind generator costs 3.7p, offshore 5.5p and that's without the cost of standby generation or storage and without the cost of getting it to England.

The British government have announced the building of new gas fired power stations in the short term and new nuclear stations in the long term. England is going to be on the European super grid, they already have HVDC lines to France and Holland. Scotland will be at the end of a very long branch line. There are no high capacity links between Scotland and England yet, the Beauly Denny line is being upgraded and an undersea cable from Ayrshire to Liverpool has been given the go ahead.

I'm all for renewable energy and all for your pumped hydro scheme and I hope Scotland will be able to produce a large portion of their electricity from renewables and store it in your dam but we have to be realistic about it, we can be self sufficient but we will never be rich, it isn't a cash cow.

 

Well up on what is going on South of the border to some extent or are you? Grids all right you think? Green Energy not. Seems to me you are just giving the Tory line again as they go against their Election commitment and losing out on investment. Not Scotland though

http://www.guardian.co.uk/environment/2012/feb/26/wind-energy-fears-government-commitment

Now that is just my 2 cents worth but if you read the article it does not look like England is making good choices.

I know Mr Dow will be back to answer you shortly.

 

If you read the article it says the same as I did, onshore wind power, the cheapest form, costs 7% more than oil or gas. Do you choose to go to the filling station that charges 10p a litre more? Neither will businesses deciding where to locate to.

 

You don't say why?

Let me guess. Were the towers constructed using mild steel which rusts through fairly quickly?

There is another way.

Or there's always stainless steel.

Anyway, the US like everyone else is being blown along with the rush to wind power.


Wikipedia: U.S. Wind Generation Capacity by Year

So clearly the Americans are not put off the economics of wind power by their 80s-built "mostly derelict" wind farms.

• and including the subsidy the French give nuclear energy for reasons of national domestic security of supply and to give them a supply of plutonium for their nukes
• but not including the insurance for nuclear accidents which again is picked up by the tax-payer as the people of Japan are finding out now.

Which is why we could build a tunnel there by excavating less rock than I need to shift to build my hydro dam scheme at Coire Glas - about 400 million tonnes worth.

What's the source for your figures? If generators last a lot longer, the capital can be repaid over more years, bringing the price down.

Well gas short term makes sense - at least until we can bring new-build pumped-storage capacity on line to complement the additional wind power capacity that's coming.

New nuclear I have to question the wisdom of.

Yes we export power down that long branch line.

Sounds good.

In terms of operating costs, pumped storage hydro is a cash cow. Put aside capital costs to build the dams, tunnels etc. for a minute and realise that if there is an excess of wind power, it costs you next to nothing to import and to store the power, then you export and sell it back at a profit while under-cutting all other non-renewable sources of power.

OK, the capital costs are huge for pumped storage but you need to look at those costs in terms of an infrastructure investment that is going to last generations.

Now, if the economy and business was booming and there was no unemployment then you probably wouldn't choose now to build lots of new pumped storage capacity - you'd wait until the economy was quiet, stalling, needing a boost - like it is now.

It just makes little economic sense for the Bank of England to pump billions of pounds into quantitative easing when the same money could be better invested intelligently in necessary infrastructure such as pumped storage hydro.

 

Wind Farms .
Those ugly things that don't work 75% of the time on average , and need back up fossil based electricity generators to support them ?
Them , as distinct from a group of Scots gathered together ?
The joke of the first quarter of the 21st century .
Just get out there and build a few Thorium reactors and shut up .

 

Yes we do but nothing like as much as the wikipedia article says. If you follow the link to their reference you will see this.

It's peak not average, there is a big difference. Plus less than 3 GW of the 11 GW is coming from Scotland and only 1 GW from north of the Clyde.

 

I saw this diagram.



I presume the figures are MegaWatts?

If so this indicates that the peak power demand in Scotland in 2009/10 was 5662 MegaWatts.

So to comfortably and confidently supply just our own Scottish power needs then 6 GigaWatts is a nice round minimum figure to aim to always have capacity to supply.

Clearly, we have no problems supplying our own 6 GW from the mix of generating capacity we have now.

However, consider now the worthy goal of a supplying 100% of Scottish electrical power needs from renewables alone.

How then to meet that 6 GW need when there is no wind blowing?

The grid in Scotland needs to add much more energy storage capacity than it has now and it needs to to add transmission capacity to take the energy from where it is stored to where it is used.

Considering the SSE's plan for a pumped storage hydro scheme at Coire Glas, the SSE only intend a 0.6 GW turbine generator and perhaps the same again from a similar scheme at Balmacaan.

So although the SSE are showing willing and pointing in the right direction, the size of their plans doesn't mean the challenge of 100% renewables supply to Scotland.

Whereas my plan does.

My bigger plan for Coire Glas offers about 20 times more energy stored, 600 GW-hours, enough for 100 hours of supply at 6 GW - keeping the lights on in Scotland, using only renewable energy.

You need to plan enough capacity to meet your peak demands under any circumstances.

Well I'll need 6 GW transmission from the north to the south of Scotland just to meet the Scottish energy needs.

But a 600 GW-hr energy store at Coire Glas could also supply 8.5 GW for 70 hours or 12 GW for 50 hours - and that would be very useful too, for two reasons.

1. Providing an energy store for the grid in England.

2. Providing more heat energy in Scotland from renewables as well, so that we can offer consumers a cheaper alternative to gas, coal and oil heating of homes, offices etc.

For those two reasons, I would install 12 GW generators and transmission capacity for my Coire Glas hydro scheme alone.

Next we'd have the option of building a few more pumped-storage schemes the size of my plan for Coire Glas and then Scotland could provide energy storage facilities -

• Either for all of the "British national" grid
• Or to make profits for an independent Scottish economy by energy import/export.

Whatever the politics, Scotland has the geography to site pumped storage hydro dam schemes to supply renewable energy 100% of the time.

The investment required can come from re-allocating "quantitative easing" cash and this the way to go to get 100% renewable energy supplied under all circumstances.

 

But you cannot get away from the fact that England needs Scotland's green energy to meet it's obligations

http://newsnetscotland.com/index.ph...scotlands-renewable-energy-admits-uk-minister

 

Really knows his way to a Liberal Democrat's heart that Ed Davey.

Doubt we'll be meeting those targets anyway but what the hell if it gets a few Liberals voting against independence.

 

Any good hydro dam scheme ought to include flood prevention measures in the land below the dam. Even at full power and emptying the reservoir, people should keep dry feet and dry houses!

My Coire Glas/Dow scheme has thought of that too.

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.




Click to see larger image

New waterway

Loch Lochy is separated from a neighbouring loch, Loch Arkaig, by a 2 km wide isthmus, which I have identified on this map 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.




Click to see larger image

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 and this is also useful for determining the appropriate size of the new water channel between the lochs.


Ease my quantity!

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 scare 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.

 

Sorry, I do not agree with putting on a blindfold and denigrating the discussion to bulling and an opinion as factual!

If you look at the Corran Narrows a mile wide 35 metres deep and a tide flow of 7 knots. For the tide to turn is about one minute on occasions, and no detriment to the nation of Scotland!

There are so many other areas akin to this, no need for idiotic plans!

Regards
Highlander

 

Well neither do I so I think we are agreed on "no bulling" and "no blindfolds".

Well we can look at the Corran Narrows if you like Highlander.

Here's a photograph of the ferry there.



Wikipedia: Corran Ferry

And I have attached an annotated satellite photograph image from Google to this post which show the narrows are about 200 metres wide, more than 200 yards but nothing like a mile wide.

I'm not entirely sure why you want to but we can certainly look at the Corran Narrows if you have a point to make about them in regard to my scheme for Coire Glas.

Is your point to do with my proposal to create a new narrow channel between Loch Lochy and Loch Arkaig, so as to allow the water flowing down from Coire Glas into Loch Lochy also to flow into Loch Arkaig, so as to keep the changes in the depth of the loch to a manageable 15 metres rather than a less manageable 25 metres which is what it would be without the new channel between the lochs which I propose?

My proposal is not to create a narrow channel of water for its own sake. There is a reason for suggesting this.

The reason would be to allow water to flow from Loch Lochy into Loch Arkaig and back again to reduce the big swings in depths of Loch Lochy which my bigger scheme would cause.

The Corran Narrows can't help with that because the water from Loch Lochy can't pass through the Corran Narrows because the Corran Narrows are a constriction in Loch Linnhe.

It's not the depth of Loch Linnhe that is a concern, that would change. It wouldn't. Loch Linnhe won't be effected at all really by the Coire Glas scheme. So mentioning the Corran Narrows is neither here nor there in this present discussion.

It's the depth in Loch Lochy that is the concern, that would change when the Coire Glas hydro dam scheme's pumps and turbines are working. For my bigger scheme there is a need to moderate the bigger changes in depth of Loch Lochy that would be caused by the hydro dam scheme's pumps and turbines working.

There is also an electrical power need I am concerned about which is the need to provide a bigger pumped storage hydro scheme than the SSE propose for Coire Glas.

The SSE's plan for Coire Glas is a good wee start but there is a need for much more pumped storage capacity than that in future as we add more wind farms that need more pumped storage to smooth out the power the wind farms provide, so as to supply stored wind energy as power when its calm as well as instant wind power when it is windy.

So there is a need for more and bigger pumped storage hydro dam plans and creating the new channel between Loch Lochy and Loch Arkaig would allow my much bigger plan for Coire Glas to work much better.

This attached thumbnail shows the Corran Narrows if you click on it.

 

Geology of the Coire Glas site
I have been able to extract this information from the British Geological Survey (BGS) Geology of Britain viewer, from the 1:50 000 scale map.




Click to see larger image

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" 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.

 

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




Image also hosted here

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 ot be 83 metres then the dam will be 400 metres tall.




Image also hosted here

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.

 

[ame="http://www.youtube.com/watch?v=asUa1PFix1A"]Spirit of Ireland, Seawater Pumped Storage Proposal, Shorter video - YouTube[/ame]

Video which illustrates the principle of using wind turbines and pumped storage hydro dam schemes together.

 

See my new topic in the Science & Technology forum.

Wind farm power and energy equations

 

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.

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.




Image also hosted here.

So my idea is that the top layer of the 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 out under 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 under the dam 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!

 

My second take is to use drain-pipes through the base of the dam which now extends all the way down to the bed rock with the drain-pipes built in, instead of continuing the bed drain under the dam as I had at first.

The large embedded image in the above post is remotely hosted on my forum so I was able to change that there. However, it is too late now to edit the above post to change the small image and the link to the postimage.org host and neither can I change the attached image.

So I am posting the new versions now.


Image also hosted here.

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.