Pumped-storage hydro dam schemes to store wind energy (Scotland)

[Local diggers]

Bahh i didnt get a reply regards my funding his lifestyle and research time...

[Muz]

Ok heres my plan .. Honest

Its the Muz Hydro thingamy tidal project . its valid and Ive thought about it for years and wondered why no one else has done it yet ?

well I suppose its not going to be well recieved cos .. in Ideal situations it will blow most fifers out of thier beds

[ianoz]

No Doubt the concept works , Otherwise SSC would not want to build their project in the first place . To make your project bigger , does not mean its better .
But no doubt they have crunched all the numbers to come up with that project . The key to the whole project is the "cheap off peak power " is the key to it .. If that power is not available in the quantity needed .You have a Giant White Elephant on your hands .

[Stock]

That system is in wide spread use,but like I said earlier it is a store of energy to allow for generation at peak times then uses cheaper off peak energy to replenish the upper loch. the weight of water can cause earth quakes as has happened in China and south America.
The level of investment would be prohibitive and regardless of who is paying there must be value given. There has to be a return on the investment and looking at it from that point of view it does not make sense. I am not fan of wind turbines for lots of reasons but mainly due to their intrusion on the land scape. the use of smaller biomass units is a better system for all.............. in my opinion.

[245dlc]

Here in Canada and especially so in the provinces of Quebec and Manitoba we have lots of hydro electric power, some of the biggest dams in the world are the James Bay Project in northern Quebec where they have experienced small earthquakes because of the weight of the water on the land and this in an area of Canada with the least seismic activity.

[Muz]

So I should have expanded on my idea but I got interrupted last night

Ok this plan refers to Scotland as we are an Island (of sorts )

What we need is a massive pipe that connects the west coast to the east coast, and because of the tidal variance between the two coasts, you would have a constant difference in water levels of some 4 - 5 meters perhaps more, and this constant change would be able to drive some sort of turbines without any need for power recuperation. I'm sure you could select the most differentiate points to gain the biggest tidal surge advantage, but its an endless form of enery, day or night, rain , hail, wind or snow.

[Stock]

Muz didn't tom telford build something similar??????????? but a wee beastie got in the way

The greenies wouldn't want any type of work in that area now..........................

[Peter Dow]

Wind farm power and energy equations

"Dow" equation for the power and energy output of a wind farm.

"The power and energy of a wind farm is proportional to (the square root of the wind farm area) times the rotor diameter".

In his book which was mentioned to me on another forum and so I had a look, David MacKay wrote that the power / energy of a wind farm was independent of rotor size which didn't seem right to me considering the trend to increasing wind turbine size.

Now I think the commercial wind-turbine manufacturing companies know better and very possibly someone else has derived this equation independently of me and long ago - in which case by all means step in and tell me whose equation this is.

Or if you've not see this wind farm power/energy equation before, then see if you can figure out my derivation!

No takers for the derivation challenge huh? OK then.

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




Larger image also hosted here

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

Compact formation




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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)

Ratio of diameters




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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 lake 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.

[Peter Dow]

Peter , It is good to see you coming back and trying to answer the questions asked.

Well it's a pleasure to come back and answer serious questions and points like yours are.

In regards to my questions about catch dam to return the water ,your google maps show no elevations ,and not being a native of Scotland I know little of the area .. It seems to me that Loch Arkaig .would need its capasity increased to hold the extra water released into it . Raising its height to catch and store the water for returning to the systemi would imagine would reduce the pressore head on the water lowering the generation output ..

The surface elevations of the lochs are shown in this diagram, as they are now, and as I propose them to be during the operation of Coire Glas / Dow / 600 GW.Hrs.




Click to see larger image

The natural surface elevation of Loch Arkaig now is 43 metres. The natural surface elevation of Loch Lochy now is 29 metres.

The act of building a wide and deep water channel between Loch Arkaig and Loch Lochy would equalise the elevations of the two lochs. Immediately some of Loch Arkaig would drain into Loch Lochy never to regain its original level. So with my proposed scheme in operation, the two lochs would, in future, in effect, act as one big loch. The new "natural" elevation of Loch Arkaig would become 29 metres, the same as Loch Lochy.

Now when water is pumped up from the lochs into the upper reservoir, up Coire Glas, then the level of the two lochs would be lowered, down to 14 metres or so. So that leaves plenty of capacity in the lower lochs for the water returning back down from Coire Glas when it is used to generate power.

Coire Glas is about 500 metres higher so the difference between the lochs operational levels, from 29m to 14m will only make a small difference to the pressure head that the pumps need to pump up and the turbines use to drive them.

[Peter Dow]

What the the volume of water released per hour.

Well to produce 12 GW of power that would be around 8 Mega.metres-cubed per hour - 8 million cubic metres.

What is the size and capasity of the pumps required toget the water back up and the time needed to pump rge water. How much power is needed to run these pumps.

The common practice in pumped-storage hydroelectricity is to use combined turbine-pumps and one example of that was input pumps which were operated at 95.5% of the rated power of the turbines.

The overall efficiency of that example installation was that you got back about 74.8% of the energy you put in.

So if those same types of turbine pumps were installed at Coire Glas then to get 600 GW.Hrs of energy out, you'd need to put in 802 GW.Hrs of energy using the pumps.

Now the pumps are operated at a rating of 95.5% of output power so the maximum input power, if you were to run all the pumps would be about 95.5% of 12GW which is 11.46 GigaWatts and at that rate it would take you 802 GW.Hrs / 11.46 GW = 70 hours to fill the reservoir up from empty.

But 70 hours would be at full power - there is no need to run all the pumps - you would run only the number of pumps that you had surplus wind power for at that time.

For example, if you only had 1GW of surplus wind power then that's all the power you would use for the pumps - 1 GW.

How many wind generatorsw are required to preduce the power

As I say, you are not required to run all the pumps at once but if you wanted to, you would need at least 11.46GW capacity of wind turbines just to power the input pumps at full power - but in practice you would want more than that because there is likely to be some demand at all times, even on windy nights, so you might want oh, maybe, and this is just a guess, 15 GW capacity worth of wind turbines? The more wind capacity you have the better really. Most of the time the wind turbines don't deliver their full power so even if you had 30GW capacity of wind turbines operating at 1/3 power, delivering 10GW of power, I think you'd not be unhappy with all that power, you could use it to keep the reservoir topped up for days of calm.

..Some how i think by the time all the costs are added up It will be far too expensive.,

Too expensive for the electricity companies. A 20 times smaller hydro scheme at 30GW.Hrs is about all they can afford.

for the people of Scotland to Pay for ..

Well if we Scots get a grip of our Scottish government and establish a Scottish central bank, like the Bank of England, then we can print the extra Sterling we need to pay for this. What we can afford is what we have spare productive capacity to produce and we have a lot of unemployed so we could easily afford a £20 billion project over 3 years which would be about 5% of Scottish GDP per year for 3 years. It would be a significant national project no doubt but it could be done, if there was a will to do it.

The way i understand AC power is that it can not be stored , Find a solution to that <You will make a name for your self .

Well look ianoz pumped storage hydroelectricity schemes to store electrical power do exist and have done for many, many years. Our first in Scotland was working in 1966. Get yourself an education from Wikipedia: Pumped-storage hydroelectricity

[Peter Dow]

The trouble is you are taking a "just about" cost effective form of renewable energy, then taking it and removing the benifits by changing the state of the energy 5 times at least.... each time you can expect to loose power, that's without mentioning the loss due to friction. this loss is what would happily kill it.

As I mentioned, you get about 75% of the energy back that you put in. This is the way it is done, now, if you want to store up surplus energy for times of large demand.

there are much more cost effective and reliable ways to generate power. tidal and waste to energy are two very good ones. your's I'm afraid is far too large and under engineered.

Well wind energy seems to be expanding the fastest and at its present rate of growth, looking at the estimates for how much more wind power is coming in future, it looks like there will be a big opportunity for pumped storage hydro-electricity to complement the wind turbine generators.

Yes there will be a place for tidal and others when they finally get going but it looks like the momentum is with wind right now.

Wikipedia: Wind power in the United Kingdom

At the beginning of March 2012, the installed capacity of wind power in the United Kingdom was 6,580 megawatts (MW), with 333 operational wind farms and 3,506 wind turbines in the UK.[1] The UK is ranked as the world’s eighth largest producer of wind power.

723 MW of new wind power capacity was brought online during 2011, a 40% decrease on 2010. 2012 is expected to be a significant year for the offshore wind industry with potentially 5 farms becoming operational with over 1,300 MW of generating capability.[2]

Through the Renewables Obligation, British electricity suppliers are now required by law to provide a proportion of their sales from renewable sources such as wind power or pay a penalty fee. The supplier then receives a Renewables Obligation Certificate (ROC) for each MW·h of electricity they have purchased.[3] Within the UK, wind power is the second largest source of renewable energy after biomass.[4]

Wind power is expected to continue growing in the UK for the foreseeable future, RenewableUK estimates that more than 2,000 MW of capacity will be deployed per year for the next five years.[5][non-primary source needed] By 2020, the UK could have more than 28,000 MW of wind capacity.

I just don't think you will find that biomass burning or others can step in quickly enough to fill the gaps when the wind goes calm.

Yes I could see the two - pumped-storage and biomass/waste burning - working well together.

The pumped storage turbines can step in right away as soon as the wind drops then if it is a prolonged calm over many hours and days then the biomass power stations firing up and replacing most of the missing wind capacity load as and when biomass power stations get up to full power output.

your's I'm afraid is far too large and under engineered.

Too large? I don't think so but it is a nice change to read that instead of someone saying my Coire Glas hydro dam scheme can't store enough energy for a 100% renewable solution to Scottish electricity needs.

You might argue 12GW power is a bit much for Scotland's present needs but then more capacity would be useful to make inroads into wind and pumped-storage supplying more of Scotland's heat energy needs. So 12 GW is more than enough for now but it allows additional capacity for expansion.

I'd be interested to read an argument which says that 600GW.Hrs is too much, too large a renewables energy store. What about for storing some English surplus wind power as well? Then it can't be too large an energy store.

Current Scottish peak power demand is around 8.5GW, including some exported power and which could be supplied for 600 GW.Hrs / 8.5 GW = around 70 hours, not quite 3 days. So I guess that is plenty long enough for Scottish current needs while biomass power stations are fired up in case of a prolonged wind calm.

But the idea I proposed is that Scotland has the geography for pumped hydro electricity schemes and so with the increased capacity of power lines running from Scotland to England there will be an economic opportunity to store surplus English wind energy and supply it back to England when England is becalmed, at least until such time as English biomass power stations can reach their full power output.

As for "under engineered" what can you mean? How can a scientist like myself offer something scientific which is "under engineered"? I will let professional engineers do the engineering. I am just providing the science to back up the vision and concepts. The science behind my vision is good. The detailed engineering I will leave to the professionals.

If you mean I have not published full plans showing where every nut and bolt gets placed, then OK. But then, after all, this is just my "vision" - not full blueprints for the scheme.

[Peter Dow]

Current Scottish peak power demand is around 8.5GW,

I am correcting that to say "Current Scottish peak power generation is around 8.5 GW."



Unfortunately, this forum does not give much time to make corrections by editing the post.

[Stock]

I agree it has potential but as I have said previously the cost of such a project would be better to create an indigenous industry instead of a huge construction project requiring imported skills and labour.Smaller is better put the money in to the communities create jobs that can't be sent to India or China.

[Peter Dow]

Nonetheless, what I see is a re-think of the perpetual motion machine that is an impossibility by today's technical understandings. Pumping water uphill to generate electricity by gravity-fed turbines is a net-zero or net-negative scenario.

Pumped-storage hydroelectricity is used now and no-one thinks it is a "perpetual motion machine" and only confused people like you think anyone does think it is such a thing. Please get yourself a basic education about it from Wikipedia: Pumped-storage hydroelectricity
and stop assuming if you don't know about it, it doesn't exist or it doesn't matter if it does exist. Many important facts about this world you have still to learn.

If you augment the electric power from wind turbines, it still doesn't matter. Why not just use the electric from the turbines to supply the power? A waste of time, materials and energy are the end result of your scheme to which there is no foreseeable payback.

OK I see you did not watch this video, or if you did you were not paying attention. Watch it again.

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

Note how the pumped-storage hydro dam supplies power when the wind is becalmed.

[Peter Dow]

100 years from now ....

Where do we draw the line between power generation and environmental damage? I suppose you could argue nuclear is the worst of all in some respects, but it doesent scar the whole country with turbines or dams ? ...but its legacy last for years all the same....... difficult one

Well nuclear has other uses - such as weapons and powering submarines, but I say draw the line at nuclear power stations for electricity generation for the grid when there are so many better solutions.

Talking about "environmental damage" it gets as big and expensive as the Sellafield nuclear site clean up, which costing about £20 billion might be about the same as I guess my hydro dam scheme might cost.

World’s 10 Largest Construction Projects

Sellafield Nuclear Site, England

$30 billion

Sellafield is the U.K.'s primary nuclear-fuel reprocessing facility. Located in Cumbria, 70 miles north of Liverpool, the plant covers 700 acres and employs 11,000 workers. Perhaps most notably, it is home to world's first commercial nuclear power plant, Calder Hall, which ended its 47 years of duty in 2003. In 2008, Nuclear Management Partners Ltd. (a consortium made up of Amec, URS and Areva) was hired to operate, clean up, and ultimately decommission Sellafield. The process will take more than a century. By 2120, the NDA expects the Sellafield site will have achieved brownfield status.

So $30 or £20 billion down the Sellafield nuclear drain and after one hundred years what will we Britons have to show for it? Nothing but a brown field site but that's progress compared to the hell that is Sellafield now! :angry:

Whereas one hundred years after my hydro dam scheme was built it would still be providing clean, almost free energy to the people!