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War of words over wind power

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Published Date: 02 February 2008
It was with horror and dismay that I read that Scottish ministers have now begun to make up their minds to veto the Lewis wind farm project (your report, 26 January). How on earth – literally – are we going to meet the new (much too feeble) targets, regarding electricity generated from renewable sources, if "environmentalists" keep screaming "murder" each time something is done to start to help save the planet?
The moors surely will fare well enough, even with wind turbines on them. Protecting a beautiful view is all very well until we are left with no beautiful view to protect. I can't help but wonder whether the opponents of these and other renewable sche
mes have thought about these alternatives. If we were to bury our heads in the sand and continue to use up the earth's resources and drown her in rubbish, our children will certainly pay the price.

KARIN KREMER
Millbank Road
Munlochy, Ross-shire

It is good news that the Scottish Government is "minded to refuse" the application by Ameco to build up to 176 wind turbines on the peatlands of Lewis. This at least gives time for reflection and discussion.

Electricity produced by wind power is 50 per cent to 100 per cent more expensive than that produced by coal, oil, gas or nuclear-fuelled power stations. But more importantly, wind power has to have 100 per cent back-up for the time when the wind is not blowing. This increases the cost further due to the capital expense of the back-up power station(s). So why not just build more "back-up" power stations and forget about the wind turbines?

The last thing we need are wind turbines, whether in Lewis or anywhere else. They will contribute nothing to future power generation.

JOHN H KNOX
Morningside Park
Edinburgh

One of the principle duties of good government is to provide a secure and reliable electricity generation and transmission system for its citizens, and at a cost they can afford; not least for the aged, the sick or infirm, and those living in fuel poverty.

Wind turbines on any scale are but a sop to conscience and, in respect of climate change and global warming, are mere gesture politics. Until the problem of energy storage is solved economically, they will remain a wholly unpredictable and unreliable way of generating electricity for the foreseeable future, and therefore cannot be relied upon to provide for this nation's needs without back-up support from conventional generation plants.

NEIL McKINNON
Tulchan Garden
Glenalmond, Perthshire

Alex Salmond constantly talks of Scotland's future as a low-carbon, renewables powerhouse, but, at the same time, his government rejects plans for Europe's largest wind farm, on Lewis.

At the same time, nuclear power gets the thumbs down. Is there an energy strategy at all there in Holyrood? Never mind, surely we can tolerate the inconvenience of power cuts knowing that the undistinguished bog in Lewis is undisturbed.

DONALD McBRIDE
Craigleith Hill Crescent
Edinburgh



Page 1 of 1

  • Last Updated: 01 February 2008 8:54 PM
  • Source: The Scotsman
  • Location: Edinburgh
 
1

Greenheatman,

TAIN 02/02/2008 05:46:38
Using wind power is this simplistic way, ie wind blows, turns a shaft, produces random electricity, is NEVER going to save our one and only planet.

A coal fired power station generates a lot of heat and only 1/3 of this heat is converted to useful and secure electricity. This is a well known fact.

100% of all thermal stations are close to either a river or the sea (for cheapskate cooling purposes), or have cooling towers to dump 2/3 of the all heat generated at them.

A logical approach would be to uses all the available renewable energy sources available such as solar,wind wave and tidal to preheat the water to say, 250C, before it goes into the coal fired boilers. A much reduced tonnage of coal will raise the temperature of the water the rest of the way to something like 500C.

Every day we know just how little time and electricity it takes to boil a kettle if the water is already hot. Conversely, we know just how long it takes to boil the same kettle if the water is stone cold.

It will be interesting to see how this 'energy' debate pans out - of course my post will be ignored as both camps slug it out with their inane and ill-considered polarised points of view.

Renewable energy in its present format is going NOWHERE!
2

Gdgy,

dndy 02/02/2008 07:58:27
Wind frams could make a contribution to our power problems - they have problems - they don't work all the time so base power has tobe supplied from elsewhere - but they represent low C energy and they substitute for oil, gas and coal generated power which means that these resources can be used elsewhere or will last longer...
I think that the anti-wind power lobby would be anti-anything new and anything in their areas - if the other possibility is reliance on nuclear for evere I say lets try wind, tidal, solar etc.....
3

Greenheatman,

TAIN 02/02/2008 08:18:30
"It will be interesting to see how this 'energy' debate pans out - of course my post will be ignored as both camps slug it out with their inane and ill-considered polarised points of view."

That's the first one to ignore my points of view already!
4

Isonomia,

Lenzie 02/02/2008 08:29:16
It comes down to the simple fact that the Lewis wind farm was not sustainable. Sustainability was developed as a concept after economic development in the 1970s failed because the economic development had inverse impacts on the environment and society so that the overall effect was detrimental.

The lesson learnt was that economic development had to be "sustainable" and take a larger view considering the social and environmental impact of e.g. agricultural change which caused farmers to start ploughing up soils that then got washed away leaving them worse off than before the economic development.

The same lesson should have been learnt about Scottish wind. This environmental development that provides next to no jobs in Scotland, and even less in Lewis, but which was bound to severely reduce the number of tourists going to Lewis, was clearly a non-starter from the beginning.

A sustainable wind policy should take account of the economic social impacts of wind both at the Scottish and local site level. And, e.g. if wind makes a few already rich land-owners and shareholders incredibly wealthy and destroys the tourist trade for B&Bs, puts those involved in tourism out of a job ... then it is not sustainable!
5

fred bloggs,

Edinburgh 02/02/2008 08:53:44
John Knox promulgates the myth that wind needs 100% back-up. This is not true. No power source is able to operate 100% of the time. Demand varies more than supply and the grid operator always has a choice of which of the available sources to use.
The morning power surge is a much bigger swing than anything our small wind supply can impose.
6

calum,

Banchory 02/02/2008 09:05:51
So environmentalists want wind power to save the planet and environmentalists don't want wind power to save the fragile landscape. Karin, your viewpoint sums it all up and encapsulates the utter confusion that this so-called renewable energy source produces - too much heat and very light light. Pass the meusli, darling.
7

Greenheatman,

TAIN 02/02/2008 09:15:14
Fred Blogs stated "John Knox promulgates the myth that wind needs 100% back-up. This is not true."

...........yes, that what it says in the BWEA website......so it must be true!

Tell me, during the week before Christmas it was very cold and still for 8 days in a row. All the UK's windmills produced zero during this time. So I think most us know that 100% backup was required for the 8 days with the wind @ zero on the Beaufort scale - "smoke rising vertically form a chimney" etc
8

Greenheatman,

TAIN 02/02/2008 09:22:39
.....Oh, and that old chestnut that even thermal plants have to close down so it ok if windmills close down too.

Thermal plants do close down for planned maintenance - windmills shut down for up to 8 days at a time subject to the random vagaries of the weather - the key word here is 'planned'
9

Colin, Glasgow,

02/02/2008 09:55:28
Greenheatman #1, you say "A logical approach would be to uses all the available renewable energy sources available such as solar,wind wave and tidal to preheat the water to say, 250C, before it goes into the coal fired boilers. A much reduced tonnage of coal will raise the temperature of the water the rest of the way to something like 500C."

This makes a degree of sense if we used a source of renewable heat, such as concentrated solar power or geothermal energy to heat the water. But neither of these is particularly accessible in Scotland. Your suggestion of using wind or tidal seems wantonly inefficient - essentially you would be converting mechanical energy to electrical (in the wind turbines etc) then back to heat for the water, then back to mechanical for the steam turbine and finally electricity for a second time. There will be significant losses at every stage.

To be honest, if we're going to use wind or tidal (or any "cold" renewables) it would be better just to use the electricity directly.

My final point on this is that the waste water/steam output from thermal powerstations is already going to be hot, and some of the "waste" heat from the thermal plant can be used to keep it hot before it is recycled back into the plant. This is surely much more efficiently than using expensive electricity to heat the water.
10

calum,

Banchory 02/02/2008 10:13:29
Dave from Barra ....... Bullseye!! All the lentil munchers and their pixie friends are quite happy to have thousands of acres of natural wilderness spoiled so that they can turn their kettle on in the morning.
Never a word of support for development in their area. And as for the "many jobs for the locals" argument .....oh, yeah!? How many local jobs for the wind farm in the Lammermuirs?.....TWO!
This renewable, windy, save-the-earth mantra is just a fashionable con. What's going to power their laptops?
BTW1 - I hope the Eigg experiment works, worth keeping an eye on for small, local, confined communities - no use for cities but maybe a less on there.
BTW2 - Didn't Barra look well on the tourism promo film?
11

n/,

Perth 02/02/2008 10:24:40
.....and for the record Dave.I have yet to see any of those who continually slag of those they call NIMBYS,countering with anything of real engineering and scientific worth other than the nonsenses spouted from the renewables industry itself,........and worse.......they dont even seem to have the courage to appear and state those views in public for example at the very many public inquiries there now have been into proposed windfarms,and all over the country. If they are so sure right is on their side........ why so shy ?
12

fred bloggs,

Edinburgh 02/02/2008 10:38:05
7. Greenheatman: 'during the week before Christmas it was very cold and still for 8 days in a row. All the UK's windmills produced zero during this time'

I don't believe you for a minute - please provide evidence.

However, let's suppose it was true. The UK wind farms have an 'installed capacity of around 2300MW. Their capacity rating is 30%. So their average output over the period would be 0.3 x 2300MW = 690MW. That is the output of half a Longannet. So, if this extremely unlikely weather condition really did happen as you claim, we would have had only to power up one coal station from 50 to 100% output!

In reality, modern wind turbines are generating power for around 80% of the time although not always at full output because that requires a wind speed of ~20mph or more.

The probability of dead calm throughout the whole UK is only 1 hour in 10 years. The probability of failure of a 1000MW coal station is much higher.
13

Jock Thomson,

Ayr 02/02/2008 10:40:23
The environmental argument against wind farms is a distraction which only serves to muddy the water. At the end of the day, if wind turbines were a benefit, then we would simply have to get used to them. You cannot have it both ways.

Unfortunately, wind farms do not work and, if it was not for massive public subsidy, they would not be on our hills in the first place. If we look at countries such as Denmark and Germany which made a serious attempt to step up their percentage of wind energy, this becomes painfully obvious.

The practical and economic arguments have been well rehearsed, however, and this is largely due to the disjointed and misguided efforts of the antis, these arguments are not getting the prominence they merit.

The end result is that the wind industry and landowners alike are being allowed to get away with grand larceny at our expense. Our schools, hospitals, roads and pensions are quite literally being thrown to the four winds to fuel this madness.
14

calum,

Banchory 02/02/2008 10:43:28
#14 I take it your figures refer to ALL the UK wind farms? And Longannet is? Yes, you're right, ONE relatively small power station. To replace all the powers stations with windy power at 30% capacity plus reserve would require the wholke of Scotland above 200m to be covered with propellors. What a policy that is!
15

fred bloggs,

Edinburgh 02/02/2008 10:44:46
8. 'Thermal plants do close down for planned maintenance - windmills shut down for up to 8 days at a time subject to the random vagaries of the weather - the key word here is 'planned''

Thermal plants have capacity factors of around 70%. They fail from time to time in a way that is not 'planned'. The coal conveyer at Longannet failed not long ago and the station was offline for ages before they got it fixed.

In contrast, modern wind turbines rarely fail - they have an availability factor of 98%, much higher than coal-fired generators.
16

fred bloggs,

Edinburgh 02/02/2008 10:46:20
16. No-one is proposing replacing all the generation with wind. The intention is to go to 20% wind and no more.
17

n/,

Perth 02/02/2008 10:49:20
......well unless windturbines produce when they are not moving,as anyone with half an eye could clearly see was happening during the many almost windless days at the Braes of Doune nr Stirling during the past few freezing weeks,you yet again Fred are up to your half truths and down right lies. Ditto during the gales. Nowt!
But it's blowing else where in the UK! Aye right!
Get the blinkers and the rose coloured specs off Fred...Scotland and those living in fuel poverty cannot afford your like!
18

n/,

Perth 02/02/2008 11:22:41
.............as for, "the intention is to go to 20% not more" Fred.#18. Are you speaking as one with inside info on this matter............or just spouting your usual broad brush tripe!
19

Neil,

Glasgow 02/02/2008 11:56:44
Greenheatman may I thank you for the single most ridiculous Heath Robinson meets Fairyland proposal from any "green" to avoid facing the fact tha there is no real problem. We can cheaply, easily & reliably have as much power as we want by giving permission to the nuclear industry to save us.

The idea of buidling both conventional & wind generators (on the same sites presumably) & using windmills (how) to preheat water, not by turning turbines, to "250 degrees" (the stuff boils at 100) so that coal can bring it to the boil, & turn turbines, thereby apparently using less energy together than they would individually (the Laws of Thermodynamics not applying in Fairyland) would not convince an intelligent 11 year old.

I suppose it is true that nearly 50% of people are of below average intelligence but 99% of "environmentalists" must be.
20

Unimpressed one,

02/02/2008 13:35:17
Karen Kremer aptly demonstrate what is so wrong with the 'green' movement. She spouts sound-bites, no doubt cribbed from FoE, WWF leaflets which themselves are highly dubious and often lies, then castigates politicians for making planning decisions based on the best technical advice. She and her ilk seek to ban everything because of baseless 'problems', but end up solving nothing.
21

n/,

Perth 02/02/2008 14:40:25
#22In making such an alarmingly silly statement as,"the moors surely will fair well enough even with wind turbines on them", I have to wonder if Karen K. even knows what a carbon sink may be and why we should not be destroying them under any guise,not least given man made climate change and catastrophic global warming,which I would have little doubt she also believes in.
22

Upbeat,

02/02/2008 14:45:44
It is reassuring to see that Fred( post 5,14.17 & 18 refer )has stopped talking about average windspeeds at last. Perhaps this is a result of having it pointed out to him that average figures for windspeed are a contrivance incorporating all high and low figures.

Above Fred now states #14 , ? catagorically ? that Longannet can produce just 1380 MW of electical energy in 8 days .

Am I right is suspecting that this figure is some average ? Is this just another attempt to confuse the issue ?
23

n/,

Perth 02/02/2008 15:26:43


#25 Bridge of Allan no less? Where else!
Bet they wished they had never been so foolish,although fools tend never to want to admit to their foolishness. If anyone needs further convincing go onto to the web site of George Monbiot,hardly one I would suggest a willing subject to involve himself in the debunking of such gadgets you would think, and see what he has to say. I think a "complete waste of space" sums up his thoughts quite nicely.However don't take my word for it, go and see for yourself not least fred bloggs!
24

fred bloggs,

Edinburgh 02/02/2008 15:33:40
24. Upbeat:

I was talking about power output in MW, not energy which would be in MWh.

Regarding average windspeeds. These are used as a first guide to where to site windfarms. However, a full assessment requires placing a test rig to measure wind speed and direction over a long period.

Since wind speed is largely a randomly fluctuating parameter, it is likely to obey a normal distribution. The average would therefore also be the most probable speed at any given moment. Your claim that in the Hebrides the wind only blows either very hard or not at all (in another thread) is therefore nonsense and I challenge you to supply evidence.

I have sailed all around the Western Isles and have experienced the full range of wind speeds from flat calm to hurricane force and every velocity in between.
25

n/,

Perth 02/02/2008 15:41:51
#26 If our politicians have there way, hospitals are also to be empowered by very similar as seen on the Michelin factory in Dundee! God help those on dialysis machines!
26

fred bloggs,

Edinburgh 02/02/2008 15:46:17
26. n:

I happen to have Monbiot's book 'Heat' at my elbow. He states:

'If we build 8GW of wind farms, they would allow us to shut down around 3GW of stations which burn coal or gas'.

This is more or less correct.
27

Colin, Glasgow,

02/02/2008 16:18:34
Fred #28, it seems wind speed doesn't follow a normal distribution. It follows a Weibull distribution (though from what I understand, for coastal sites, it is pretty close to a normal distribution):
http://www.windpower.org/en/tour/wres/weibull.htm

Onshore the most probable wind-speed at any time is below the median, which in turn is below the mean wind-speed. Offshore I think it shifts the other way.
28

Upbeat,

02/02/2008 16:25:06
Fred # 28 You never did make it clear what you were talking about at all with regard to Longannet. That a wind turbine may have a theoretical output of 1, 2 3 or 5 MW bears no relationship to its actual output, as you well know. That is why attempting to describe the theoretical output of Longannet over 8 days and compare it with wind turbines over 8 days is a foolish red herring.

As far as average windspeeds is concerned, you failed to address the point the other day before the thread was superceded by a fresh one.

You will know that while an average windspeeds does exist somewhere between max. and min. (and note carefully I never said they did not,) they are no useful way of predicting output from any wind energy project. As it happens your statement "I have sailed all around the Western Isles and have experienced the full range of wind speeds from flat calm to hurricane force and every velocity in between." sums up the problem admirably.

The additional point I made was that along the west highland coast there are few moments when the windspeed is in any way most ideal for wind turbines. Either the wind is too lttle and the output is marginal, or the windspeed is too high/extreme and - due to shut down - the output is nil.

You cannot have it both ways. You have repeatedly attempted to blind the correspondents here by referring to 'average' figures.

Tell us, how many hours per year is the wind in the Outer Hebrides actually anticipated to be blowing at the ideal speeds for maximum output from modern 3 - 5 MW wind turbines. ?

Is it possible that you simply don't know ?

(Regarding Monbiot, there will be an incentive for him to write as he does. With his agenda one should be on the look out for "spin" . Such a controversial message as his does sell books, and keeps him on the international lecture circuit gravy train. )

Conventional powerstations can never be cut by 3/8ths and replaced by windpower if a stable and dependable energ
29

Upbeat,

02/02/2008 16:27:19
contd....if a stable and dependable energy supply is required in any Nation. To dream, as you appear to , based solely on the law of averages, is dangerous.
30

fred bloggs,

Edinburgh 02/02/2008 16:29:56
31. Thanks, Colin. Very interesting. Luckily, it doesn't kill the sense of my point.
31

fred bloggs,

Edinburgh 02/02/2008 16:40:57
32. Upbeat:

Modern wind turbines start to produce power at around 4 m/s. As wind speed rises the power output rises rapidly, reaching its maximum or nameplate or 'installed' capacity at around 13 m/s. Above this speed the output remains steady until around 25 m/s above which the turbine will shut down.

25 m/s is 56 mph and corresponds to Force 10 = whole gale = trees uprooted, weak buildings collapse.

I suggest this operational wind speed range matches well the weather in the West.
32

Colin, Glasgow,

02/02/2008 16:46:45
Upbeat #32, you say "The additional point I made was that along the west highland coast there are few moments when the windspeed is in any way most ideal for wind turbines. Either the wind is too lttle and the output is marginal, or the windspeed is too high/extreme and - due to shut down - the output is nil."

Do you have any evidence for this? It sounds like wishful thinking.
33

fred bloggs,

Edinburgh 02/02/2008 16:53:47
32. To deal with your first paragraph regarding my little sum at 14, this was a hypothetical argument analysing what would happen in the exceedingly unlikey event that there was flat calm over the whole of the UK. I simply stated in essence that the lost wind farm output could be replaced by the amount of power that could be produced by half the maximum output of one coal station. What about this a 'foolish red herring'?
34

n/,

Perth 02/02/2008 17:08:46
What you seem to fail to notice is he involves himself with off shore and industrial scale wind which is still technically and cost wise an unknown. What I was talking about if you look was microgeneration ! YET MORE HALF TRUTHS FROM THE FRED BLOGGS CAMP? I have little doubt.
35

Upbeat,

02/02/2008 17:11:45
Fred and Colin.

You theorise away , what happens in the west throughout the year is known only too well by those who live there full time.

Anybody who lives along and knows the west Highlands will confirm that there are few periods when the weather is settled. Mostly this only happens when there is a large anticyclone sitting over the area. On these occasions the output from Wind turbines would be marginal.

The rest of the time windspeeds can vary from near calm to full gale within a few hours, and then , within hours the wind direction and speed will be different again.

One reason why the inner Hebrides , the outer Hebrides the northern isles and mountain areas north of the great glen are devoid of trees is because the force of the wind prevents growth.

It is not the steady wind that stunts growth , it is the gusts that tear and uproot vegetation.

Fred's evaluation of the worth of windpower, (to be polite) is based on theory. The actuality is something for which the engineers may have prepared, but which will defy the theorists. The idea that at the moment a windturbine measures a gust of 25m/s it will shut down automatically , only to restart if windspeed averages drop by ,say, 10% , is great in theory . In practice this figure will be unworkable. The turbines will have to slow to a stop much earlier, and remain stationary for much longer period is structural damage is not to occur. .

Wind in the west varies hugely over a period of minutes and hours. A sudden dramatic wind sheer , which occurs so frequently as frontal system sweep acrsoss in winter , will destroy such theory based certainty. This factor alone causes such worry that the actual wind evaluation figures for Barvas moor remain a closely guarded secret.

This is not wishful thinking, Colin, this is based on half an "average" lifetime spent close to the sea, in the west.

36

n/,

Perth 02/02/2008 17:12:39
Fred ,instaed of all the smoke and mirrors, .....similar to Dave has asked on numerous occasion before, how's about an answer to my earlier QUESTION at #20 That would be a bonus!
37

n/,

Perth 02/02/2008 17:26:17
..and to quote George Monbiot on microgeneration. "If you wish to destroy people's enthusiasm for renewables,it is hard to think of a better method". SOME ENDORSEMENT!
38

fred bloggs,

Edinburgh 02/02/2008 17:28:49
38. n:

The letters at the top are about the Lewis wind farm and wind farms in general. My first comment was specifically to the John Knox letter and my later comments were, implicitly, about onshore wind.
39

fred bloggs,

Edinburgh 02/02/2008 17:39:40
38 n:

However, regarding offshore wind you say:

'industrial scale wind ... is still technically and cost wise an unknown.'

Not so. Successful offshore wind farms have been built in various places around the UK and elsewhere. The London Array will be the world's biggest at 1000MW.
40

n/,

Perth 02/02/2008 17:41:11
#42. A cop out Fred and well you know it!
The achilles heal remains! Wind turbines are not the answer,not least to the problem of global warming and climate change if you sign up to that proposal. They are nothing but a sop to conscience and to the consumer and the taxpayer a very costly one at that.
41

n/,

Perth 02/02/2008 17:46:45
The London Array may well be the biggest. However until it is built ...........and up and running you cannot say such a thing not least given the lies and hald truths that have been spouted re onshore which daily is being seen as it truly is. A COSTLY AND WORTHLESS EXTRAVAGANCE.
42

fred bloggs,

Edinburgh 02/02/2008 17:56:02
39. Upbeat:

I just had a look at the forecast wind speeds for the early hours of tomorrow morning at midnight, 3am and 6am:

Edinburgh:
speed 20; gust 40 mph
speed 23; gust 45
speed 22; gust 49

Stornoway:
speed 31; gust 60 mph
speed 30; gust 59
speed 30; gust 54

So in both locations the gusts are roughly twice the strength of the speed.

Kind of blows your argument about special gustiness of the West out of the water.
43

n/,

Perth 02/02/2008 17:56:36
Now with all that said ......go and pick your cheque up from the renewables industry Fred........you have spouted enough tripe for one day,even by your own standards. That said please don't stop completely...........for in doing so you are injuring the renewables industry far more than all the anti campaigners across Scotland could ever hope to do,so keep up the good work!
44

fred bloggs,

Edinburgh 02/02/2008 18:00:14
'Britain's massive offshore wind power potential'

http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/10/04/eawind104.xml
45

fred bloggs,

Edinburgh 02/02/2008 18:03:45
40. n:

From the link in 48:

Electricity from offshore wind farms is expected to play a major role in helping meet the Government's difficult target of 20 per cent of our needs from sustainable sources by 2020.

Does that answer your question Dr no?
46

Upbeat,

02/02/2008 18:20:29
46 Fred

"Kind of blows your argument about special gustiness of the West out of the water"

No, Fred it 'kind of' confirms it.

In all cases tomorrow between 3am and 6 am (according to the figures you provide for Stornoway) the turbines would all have to be stationary for safety reasons. ( over 25 m/sec ). In addition while the percentage change above "average" load might be the same, (at +100% ) the range of variability ie uncertainty , is greater.

What these figures actually show is how suitable for turbines the Edinburgh area might be. Those turn bines established in Midlothian on Arthurs seat, Moorfoot and the Pentland hills would not have to be shut off in adverse and extreme conditions quite so often, so, in your theoretical world they should be better able to generate base load more of the time.
47

n/,

Perth 02/02/2008 18:40:30
No Fred...............all but dreams. The give away? "expected"!

However I see that you are a Telegraph reader.
Dearie dearie me! All very sad.
48

fred bloggs,

Edinburgh 02/02/2008 19:06:49
50. Upbeat:

The turbines would not have to shut down. They can operate in sustained wind speeds up to 56 mph and higher gusts.
49

n/,

Perth 02/02/2008 19:18:24
..and Upbeat if windturbines were built on Arthurs seat,(one of your earlier suggestions) they would be nearer to centre of need..... and of power........
at Holyrood. As Dave has already said. Fred is a NIMBY and as we also now know....reader of the Telegraph. Whatever next!
50

Greenheatman,

TAIN 02/02/2008 20:24:39
"Your suggestion of using wind or tidal seems wantonly inefficient - essentially you would be converting mechanical energy to electrical (in the wind turbines etc) then back to heat for the water, then back to mechanical for the steam turbine and finally electricity for a second time. There will be significant losses at every stage."

There are only two stages; mechanical shaft power into heat directly and stored heat into electricity.

There will indeed be losses but they will be insignificant.

"The idea of buidling both conventional & wind generators (on the same sites presumably) & using windmills (how) to preheat water, not by turning turbines, to "250 degrees" (the stuff boils at 100) so that coal can bring it to the boil, & turn turbines, thereby apparently using less energy together than they would individually (the Laws of Thermodynamics not applying in Fairyland) would not convince an intelligent 11 year old."

Clearly, your grasp of thermodynamics is wayward to say the least water will not boil at 100C in a pressurised container. Water @ 500C will not boil if the tank is pressurised to 165 Bar.

The shaft power can be directly converted to heat on the basis that you cannot create nor destroy energy.

Maybe you do not know that Law of Physics!



51

Colin, Glasgow,

02/02/2008 20:43:40
#39 upbeat, you say "The rest of the time windspeeds can vary from near calm to full gale within a few hours, and then , within hours the wind direction and speed will be different again."

Ok, convince me. Show me where this happens. Here is last month's hourly data:
http://www.metoffice.gov.uk/education/archive/uk/

There are certainly a few days of calm, but on the whole the wind conditions look good.
52

fred bloggs,

Edinburgh 02/02/2008 20:56:26
I would not be against the erection of one or two wind turbines in our fair capital in a few carefully chosen spots.

One suitable site might be the reclaimed Platinum Point which projects into the Forth and would catch some clear wind provided the hideous new housing towers are demolished.

Another - more of a 'brownfield' site - might be the Seafield sewage processing works. On a windless day putting the turbine into reverse would help blow the smell away.

Then there are the 'upturned boats' adjacent to the Palace. Even what Dave the Barraboy calls 'windmills' (though they don't grind corn) could not make that 'iconic' building more incongrous with its surroundings.

So you see I am not a NIMBY at all.
53

Colin, Glasgow,

02/02/2008 21:05:23
Greenheatman #54 "There are only two stages; mechanical shaft power into heat directly and stored heat into electricity."

Ok, that makes a little more sense, but how are you going to transport the heat from the renewable source to the thermal plant? Are you proposing to move the thermal plant to location where the renewable source is optimal?

And what size of renewable resource will it take to raise the temperature of all that water to 250 degrees? As Fred has pointed out, it takes all of the wind turbines in the UK to produce the energy of half a thermal powerstation. I presume that you are not really suggesting wind power for this, because you couldn't fit enough wind turbines close enough to the thermal plant.

Also, I would like to know how you are proposing to store heat with no significant loss. In fact I imagine every coal and nuclear operator would like to know this. If you can do this efficiently then you can postpone electricity generation from periods of low demand and use it in periods of high demand. I think entropy will get the better of you though.

Forget creating heat from mechanical energy - just go straight for electricity.
54

n/,

Perth 02/02/2008 21:19:34
One or two?..........What nonsense.
There need to be hundreds,and to catch the available wind....as high as needed. In fact a complete ring around the fair capital would be just perfect. Get lobbying the idea Fred,you know it makes sense. There's a planet to save!
55

n/,

Perth 02/02/2008 21:21:44
On the up turned boats........we can most certainly agree. It is a building of appalling dimension.The encumbants? Least said the better.
56

Upbeat,

02/02/2008 23:24:53
55 Colin

"Ok, convince me. Show me where this happens"

Well, with a link to the Met. office you seem to have identifies already where to start looking, for yourself.

A dedicated study of meteorology will show you what happens as a cold front passes a given spot on the earth's surface.

Change in barometric pressure and rapid shift of wind direction are part of the sequence....Followed by a change in wind speed. Precipitation is also associated with the passage of frontal systems, due to changes in barometric pressure.

Read up on this. Study of the basics does not take much effort ...and then you will understand what is being referred to.

Due to the fact that the island of Lewis is out in the North Atlantic,at appropaching 60 deg latitude, it is in a very exposed place. For weather systems spilling down from the Arctic around Greenland, Lewis is the first contact with land in almost 2000 miles. Weather systems are affected by landmass, and topography, which can reduce their strength. For the Islands of the 'high' north Atlantic The Faroes, Shetland, Orkney Rona and St Kilda this is not the case. The full ppower of all atlantic weather systems is also experienced on Lewis.Forces that the rest of Britain experiences only a handful of times each year, with devastatig consequences for property , are quite regular in the hebrides.

Listen to the Shipping forecast for a month or two, Colin, ...you will soon get the general idea .



57

Upbeat,

02/02/2008 23:49:36
52 Fred

You appear to be claiming that 100 metre ? 4 MW ? turbine towers are built today that are capable of withstanding Storm force (over 48 knots )conditions while generating maximum power.

Your exact words were: "The turbines would not have to shut down. They can operate in sustained wind speeds up to 56 mph (25 mtrs /sec) and higher gusts" .

Let's not get carried away.

The turbine that can operate safely in storm force winds, when gusts to Hurricane force over 65 knots (33 metres /sec) are likely, is uneconomical engineering. Even when onshore turbines are built to withstand windspeeds in excess of 65 knots the rotor would have been brought to a standstill long before then, and probably before windspeeds exceeded 35 knots (approx.40 mph). The other factor you refer to (56 mph / 48,6 knots) being a safety margin.
58

fred bloggs,

Edinburgh 03/02/2008 07:48:54
Upbeat and Colin:

The wind speed distribution and turbulence graphs here for Orkney should be of interest:

http://www.winddata.com/
59

Greenheatman,

TAIN 03/02/2008 08:20:50
"Forget creating heat from mechanical energy - just go straight for electricity."

............and go straight back to worthless intermittent electricity subject to the vagaries of wind, wave and tide.

A little contemplative thought will conclude that storing green energy as heat before converting it to baseload electricity is the only way forward.

Of course, it would be better to site these new Gentec Power Stations on say, the Pentland Firth for tidal stream, wave, (Thurso) river flow and perhaps wind inputs, but an interim solution would be to preheat existing power stations' feedwater as described above.

Another point worth making here is that the available shaft power at maximum tidal flow during the nadir of Neaps in any semidiurnal tidal stream is approximately 1/8 of the shaft power during the zenith of Springs.

Using the medium of heat means that you can 'carry forward' the excesses of Springs into Neaps thus levelling out the continuous base load electrical output across the whole lunar month.

Like I said, the big mistake is real time generation from intermittent renewables and we must move away from this dead end strategy very soon or the effects of global warming will be irreversible.


60

fred bloggs,

Edinburgh 03/02/2008 08:56:01
63.

'A little contemplative thought will conclude that storing green energy as heat before converting it to baseload electricity is the only way forward.'

Well, I've contemplated and I still don't get it.

Why not store the energy with pumped hydro? Or use it (the electrical power from wind generation) to charge the batteries of electric cars as they are parked overnight in their garages when there's lots of wind and low demand.
61

fred bloggs,

Edinburgh 03/02/2008 09:10:33
61. For most turbines the speed at which the rotor will be stopped and parked is 25 m/s or 56 mph. Loss of production from this is limited as sustained wind speeds of this strength are relatively infrequent.
62

Greenheatman,

TAIN 03/02/2008 09:55:08
"Well, I've contemplated and I still don't get it.

Why not store the energy with pumped hydro?"

.........because you would need around 400 'Cruachans' with pumps running on thermal power stations' outputs every night to put the water back up the hill.

Further, this electricity for the pumps is produced with a thermal efficiency of 34% and pumped storage has an efficiency of around 70%.

An overall efficiency of around 23% is not very good so we can forget pumped storage as a viable option.

63

Colin, Glasgow,

03/02/2008 11:01:25
Greenheatman, what efficiency are you expecting to get from heat storage? Pumped-hydro is relatively efficient storage at 70% because it is cold. (Your point about the inefficiency of the thermal powerstation running the pumps is irrelevant when we are considering how to store energy from intermittent renewables. The pumps would be running on wind power etc when it was available, and _that_ would be stored with 70% efficiency.)

Compressed air storage is less efficient because it loses energy from heat. High temperature storage will be less efficient and the hotter it is the more energy it will lose. It is preposterous to suggest that we could store GWh of energy as heat without significant losses. If this was possible, we would have been doing it a long time ago, and base-load thermal plants would be using this technology for load-following.

Sure, there are inefficiencies involved intermittent electricity generation, but they would be dwarfed by the inefficiencies of your thermal storage suggestion.


The best solution at the moment, given that we don't have ample pumped storage, is just to keep the supply of intermittent renewables at a manageable level, say below 20%. Fill the remainder with nuclear baseload, and top it off with whatever hydro we have plus some gas generation to provide backup/peak supply. Longer-term, new modular nuclear reactors will be capable of load-following.
64

Neil,

Glasgow 03/02/2008 13:12:12
Storing power as heat is an extremely silly suggestion. It is the nature of the universe that heat escapes (those pesky Laws of Thermodynamics again). A little contemplation together with a very little knowledge of the subject would have shown Greenman that.

He is hopwever quite right about pumped storage not being practical either. Which in turn means the entire "renewable" industry, which, except for hydro which they hate anyway, depends on intermittency, is a non-starter.
65

fred bloggs,

Edinburgh 03/02/2008 14:25:37
From the DTI Wind Energy Fact Sheet 11:

'Wind Energy and the Electricity Network '

'Studies in the UK have shown that intermittent generation, such as that from wind power, can supply up to 20% of peak demand without the need for significant changes to operating practices. For the levels of wind power generation likely in the foreseeable future, the loss of electrical supply to the system from wind can be treated like any other generator loss. The reserves needed to guard against loss of a large power station will readily cope with the very small additional perturbations due to the wind.'
66

Greenheatman,

TAIN 03/02/2008 17:58:45
"Storing power as heat is an extremely silly suggestion. It is the nature of the universe that heat escapes (those pesky Laws of Thermodynamics again)"

Oh really! Consider this.

The energy released from 1000 tonnes of water that drops from 250C to 200C is 233GJ. This equates to 65MWh which has to be converted to electricity. Assuming a thermal efficiency of 35% this 10m x 10m x 10m thermal accumulator could supply a constant 22.6MW(e)providing a hybrid of intermittent renewables keep the temperature swing within its operating limits.

A pressurised insulated tank will not be cheap to build but, hey, we are trying to save the planet here

 

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