The (questionable) benefits of wind energy

I first read in Private Eye, over Christmas, that national grid balancing data are available on the internet, detailing the demand for electricity at any given time, and how it is being met by the different sources of supply. The Eye article was mainly about the poor showing of Britain's wind farms during the cold spell in December. I read it, then forgot about it, then couldn't find it. Google to the rescue - and I was soon led to a gold-mine of information provided by the incomparable Bill O' the Wisp, a Dorset based Neanderthaler with a keen interest in wind power (among other topics) - not to mention his keen intellect! This is his blog:

http://billothewisp.blogspot.com/

Here is his picture:



He has many posts on the push for wind-turbines, all worth reading. For now I want to draw your attention to this one (dated 9/1/11):

http://billothewisp.blogspot.com/2011/01/wind-power-damning-results.html

One of the highlights is this figure:

Figure 1

illustrating the power supplied by the UK wind-sector (or half of it, to be precise - not sure why) during 3 months from 3rd October 2010 to 3rd January 2011. The raw data give the figure in MW for each half-hour period during those 3 months. The x-axis of the graph is time, measured in units of half an hour (48 of those per day, 1440 odd per month, 4320 per quarter). The y-axis is the power in megawatts (MW)produced by about half of the installed wind-turbines in the UK, with a nominal rating of 2430MW (the other half isn't included in the data, unfortunately).

The raw average output is 608MW, equating to 25% of the nominal rating.

This is the figure that is much used by the turbine camp. 'We admit, the wind doesn't blow all the time at optimum strength. But on average, the turbine will produce 30% of its rated output.' Well, it was actually 25%, nationwide, during these 3 months - but let's not quibble about that.

Far more important is the extreme unevenness of the output. As Billothewisp puts it: 'Half the 3 months' energy arrived in less than 25% of the time leaving the other half to cover the remaining 75% of the period'. At times, as some of us already knew, the covering was extremely thin. For example, during the 21st December, the maximum output was 78MW (most of the time during that day it was considerably less), equating to 3% of the rated output.

Now, while bearing the output graph in mind, consider this statement from the Financial Times on 20/1/11:

'Capacity [of the wind sector] is set to increase from 5GW to 37GW during the next decade.'

(ref - best way to see it: put hull 37 gigawatt into google)

- that is, by a factor of more than 7. What will the output from this army of turbines look like? There are some who insist that the combination of large numbers of turbines will somehow smooth the output curve. But consider this: there are already thousands of turbines, dispersed through the UK contributing to Figure 1 above. If it were true that 'the wind is always blowing somewhere', those violent ups and downs would simply not be there. But they are.

Maybe some of the coming turbines will be spread more widely over the North Sea. Maybe that will improve the output graph. Maybe the ups and downs won't actually be 7 times as large as they are at present. Maybe they'll only be 5 times as large. But essentially we'll have a source of power whose output oscillates between say 30GW and 2GW on a permanent basis.

Links with other parts of the world could improve the situation. At present we can exchange 2 GW with France,and there is a link with Ireland (not much used during these three months).

A means of storing electrical energy could help to smooth the graph. As the BWEA website helpfully suggests, the National Grid can already cope with the famous 'TV pickup' when almost every Brit turns on his electric kettle at the end of Eastenders. This is a surge of demand of some 2.4 MB lasting for about 5 minutes. It can be managed by 'throwing water at it' i.e. by switching on the reversible hydroelectric plants in Wales and Scotland.

But when 10GW is missing for 2 or 3 days (because the wind has dropped)? There certainly won't be enough water to throw at that one.

The trouble seems to be this: just as wind energy becomes big enough to eat significantly into our carbon output, it becomes seriously unmanageable. The National Grid spokespeople seem to think they can cope with what is coming, but one always wonders, Have they just been told to say that everything's in hand, that there's nothing to worry about?

Imagine for a moment you're controlling the grid in ten years time. You have this giant resource of wind power, nominally rated at 37GW; but what is it really worth to you? How do you rate its contribution to the electricity supply? What point between 2GW (output on a calm day) and 37GW do you pick? Suppose you say, well, we all know the wind is somewhat intermittent, let's pick the level that we know the wind sector can deliver 75% of the time (by then our mindset has changed so that we don't always expect electricity to come down the pipe when we flick the switch). Another one of Billothewisp's graphs shows us what level this will be:

Figure 2

What Bill O' the Wisp has done here: he's taken the 4400 half-hour periods and arranged them in order accorrding to the wind-power output during each half-hour, with the less productive periods on the left, and the more productive periods on the right. Looking above the middle half-hour period (in this arrangement), we see that the power was about 500MW.

This implies that half the time, the power was more than 500MW, half the time it was less (a statistician would call this the 'median' power production). So an output of 500MW could only be guaranteed 50% of the time. To obtain 75% certainty one would have to move to the left, and to a power level of about 250MW. (For 90% certainty the level would be about 100MW; but let's stick with 75% certainty for now.) Now 250MW is about 10% of the nominal rating. Extrapolating to the situation in 10 years time, the 'guaranteed' level of output would be 3.7GW.

That much could be 'relied on' (75% of the time).

But quite often the output would jump up to 25GW, sometimes even to 30GW. That's a hell of a lot of surplus power to lose. There seems little doubt that the cheapest way to lose it (possibly even in terms of carbon emissions - but that's another story) would be to turn the majority of the wind-turbines off. Fortunately, this seems to be a strong point of wind-turbines, that they are easy to turn off (by altering the pitch of the blades - I think). The only snag - that you (the end-user) have to keep paying the wind-turbine owner an exorbitant price for the electricity that is not being generated.

It may be that in the fullness of time, we will learn how to make use of these great surges of power, coming at times set not by us but by the gods of the weather. Until that time comes, it would seem (for the reasons given above) that a realistic estimate of the productive capacity of a wind-turbine might be 10% (or less) of its nominal rated capacity - rather than the 30% quoted at present by the promoters of wind-schemes.

Am I missing some basic facts here? If so, I would be glad to be told what they are. Meanwhile, if you want to look at the raw data, this is the place to start:

http://www.bmreports.com/bsp/bsp_home.htm, scroll down to 'Generation by fuel type (graph)', click on the button just below the graph, labelled Current/Historic; on the page that comes up, click on one or the other red buttons at top right 'Historic Data XML' or 'Historic data CSV'. These will download for you the 3-months raw data in either XML or CSV format. The latter sort can be opened in Excel. Good luck!

glowworm awake again!

Sorry, glowworm has been dozing...

By the 30th September 2010 (the closing date for public comment on the first Mossford application), more than two hundred letters and emails had been sent to the planners, the great majority of them agin.

On the 14th October - surprise news: the application has been withdrawn.

The immediate reason given: the objection raised by Scottish and Southern Energy, owners of a power-line running along the Northern boundary of the applicant's property. The proposed 80-metre high turbines were too close to the power-line. If by any chance one should fall down, it could fall onto the power-line. The distance must be at least 1.5 times the turbine height.

Besides that immediate reason, the planners had pointed out many other potential difficulties with the application; in particular the Environmental Health Officer had questions about the predicted noise impact on the three closest dwellings, which could easily receive noise levels in excess of the permitted levels, even with the proposed 'mitigation' (i.e. running the easternmost turbine in 'reduced power mode' when the wind got too high).

The interested reader can look up the following relevant documents, all dated 14/10/2010, on the planning website (at www.aberdeenshire.gov.uk/planning/apps/detail.asp?ref_no=APP/2010/2712). They are
1)Environmental Health
2)Comments on Application
3)Email requesting withdrawal of application
4)Letter regarding Landscape Proposals
5)Officer's Comments.

The correspondence between Green Cat Renewables (the applicant's agent) and the planners indicated that a new application, with fewer turbines, was a possibility.

11th January 2011 - a new application was validated, for one 80-metre high turbine at Mossford. (Some observers had predicted that a new application would be put in some time like Christmas Eve; they were one day out - it was actually put in on the 23rd December!)

New application number: www.aberdeenshire.gov.uk/planning/apps/detail.asp?ref_no=APP/2010/4064

Expiry date for public comment: 17th February 2011

Essentially, only the middle turbine of the 3 formerly proposed has been retained, and it has been moved South in order to be further away from the power-line.

The predicted noise level at the three nearest third-party dwellings is less than it was before, but still rather close to the permitted level. The predictions could be out by as much as 6 decibels when all sources of error are taken into account.

Objections on the grounds of visual damage to a valuable landscape (Marnoch in particular, and the Deveron Valley in general) would appear to be as valid as they were before. In the balance of costs and benefits, the benefit side would appear to be reduced, as it is now just one 800kW turbine (producing perhaps 200-250 kW on average) that would be casting its shadow over a wide and hitherto unspoilt area.

For more information, and to send a comment to the planners by email, go to
StopMarnochTurbines.com.

For the bigger picture, refer as always to CAWT (Concerned About Wind Turbines, based at Cuminestown).

NIMBY and proud of it

Members of the Marnoch and Deveron Valley Protection Group have been described as ‘NIMBY hippies’ in an online comment at the Banffshire Journal website, possibly on the basis of the picture of them that appeared in the BJ.

When it comes to industrial wind-turbines, glowworm thinks that NIMBY-ism is the only sane option. Who would want a 250-foot turbine in their back yard?

For PIMBYs (Please! In My Back Yard) special housing estates could be built as close as possible to wind-farms. Wind-industry experts believe that such properties could command premium prices.

Noise

Maybe you preferred the view how it was before - but industrial wind-turbines at a distance of several miles will probably not stop you getting on with your life just as it was before the turbines popped up.

Some of us, on the contrary, think they look quite pretty going round over there - quite a nice addition to the scenery. And most of us get a bit of a warm, comforting feeling – at least something is being done to clean up our energy supply!

Closer up, the monster machines present a more menacing aspect. They are just so big, so out of scale with ordinary things round about them – trees, buildings, fences, livestock (not to mention people). I must admit, there’s a certain fascination, too. At least that’s what I find - as we all know, even quite horrible things can be fascinating...

One also becomes aware of the noise they make.

Out-and-out enthusiasts for wind-turbines sometimes deny that they make any noise at all, but anyone can disprove that for themselves by going up to a turbine when the wind is blowing. Perhaps the enthusiasts are referring to the fact that the turbines (if in good working order) are remarkably quiet mechanically. What you do hear is a ‘whoosh’ every time a blade of the turbine-rotor passes in your direction.

When the wind is light, the sound is interesting more than anything else. But as the wind gets up, the noise gets louder, and can be heard at greater distances (and not just downwind of the turbine). If your house is within a distance X of the turbine, there is a definite possibility that the noise from the turbine will be a nuisance to you. One of the problems is that the noise just goes on and on (till the wind changes): it is often described as like the noise of a train arriving in a station – but a train that never arrives; or in similar terms. Sometimes the noise is accompanied by waves of air-pressure, sufficient to cause the walls of a house to shake. In some cases the ‘whooshing’ develops into a rhythmic ‘thumping’. People find that their sleep is disturbed, and that they develop symptoms such as headaches and raised blood pressure.

All this is highly contentious, of course. The symptoms are dismissed as ‘psycho-somatic’ by the wind-turbine lobby (as if that made them any easier to bear – or can the developers show that the symptoms can be made to go away by means of appropriate psychotherapy?), the complainants as un-public-spirited whingers.

I think everyone agrees, however, that there must be some distance X from any large wind-turbine, within which it would be grossly unjust to expect anyone to live. The difficult part is to agree on a value of X for planning purposes. The developers have an obvious interest in keeping X as low as possible, but this leads to a stream of people whose quality of life is being spoilt and in some cases ruined by nearby turbines. As the rate of turbine installation goes up (in Aberdeenshire, for example) there is a danger that the number of new wind-turbine-victims will go up as well.

At present, in Aberdeenshire, there is an absolute recommended lower limit for X of 400 metres. But at distances greater than 400 metres it is recognized that the turbine-noise may be in excess of what is acceptable.

For planning purposes, an estimate has to be made of the noise that will be produced by a turbine or set of turbines at any given location. This lands us in another contentious area, for some of the phenomena that people complain of, such as shaking walls and ‘thumping’ are simply not recognized by the scientific models used to calculate noise-production by turbines. But it seems perfectly reasonable to expect that there will be something different about the pressure-waves produced by the 50-metre-wide rotor of a turbine, as compared with other sources of noise such as internal combustion engines or metal-bashing machinery. Let us not forget the huge amounts of energy being transferred from the air to the turbine blades – enough to power several hundred homes (at least momentarily), as we are told. The air will be stirred up in a very unusual, novel way.

There are now thousands of onshore turbines in the UK, from which to gather noise (and more generally, air-pressure-disturbance) data, and, I would guess, thousands of homes affected by noise from nearby turbines. Some thorough, broad-minded research needs to be done into the conditions under which human problems (including medical problems) occur. By ‘broad-minded’ I mean research that is prepared for the unexpected, for new phenomena – as opposed to the kind of research that says, there can’t be a problem because our calculations say there can’t be a problem.

Such research will be difficult, and expensive. In principle, the expense should not be a problem, thanks to the generous profits which onshore wind-turbine projects enjoy. (I am not for a moment suggesting that the developers should fund the research directly, but the cost could be levied from them.) Until the research is done, one can only support the call being made by many organizations, including the admirable Aberdeenshire-based CAWT, for a minimum separation distance from homes of 2000 metres to be imposed on industrial wind-turbine developments.

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If you agree with this argument, it so happens that there is currently an opportunity for you to influence the planning system in this regard. Aberdeenshire Council is writing a new Local Development Plan. To find out how to view the relevant sections of the draft Plan, and to comment on them, click here. Comments have to be in by 5pm on Friday 1st October.

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If you need convincing of the potential bad effects of nearby wind-turbines, a good place to start is the paper 'Wind Turbines, Noise and Health' by Dr Amanda Harry, a Plymouth GP. This research is not necessarily a model for the kind of research which I feel is needed, which will have to be extremely meticulous to satisfy both camps.

Another useful paper: 'Noise radiation from wind-turbines installed near homes: effects on health' by Frey, BJ and Hadden, PJ

One week left for objections

The deadline for public comment on the Mossford Wind-turbine proposal is Thursday 30th September.

So it's time to think about writing that letter!

For ideas (and information) go to the campaign website http://www.stopmarnochturbines.com/ and follow the link 'How to object'.

If email comes easier to you, just go to the same website and click on the round sign consisting of a turbine with 'Object' written across it. Alternatively, you can get to the same place by clicking here. Or just send your email in the normal way to bb.planapps@aberdeenshire.gov.uk.

The reference number of the application is APP/2010/2712. To see the planning documents (including letters that have already been sent in) click here.

Banffshire Journal

Besides the front-page article already referred to (post of 8th September), the BJ also published a robust leading article, under the heading 'We must draw the line somewhere'. It goes on to say that residents around the Bridge of Marnoch are quite rightly dismayed at the prospect of turbines at Mossford. Click here to read it:

http://www.banffshire-journal.co.uk/news/fullstory.php/aid/5683/We_must_draw_the_line_somewhere.html

The same issue contains an equally robust letter from a Marnoch resident:

http://www.banffshire-journal.co.uk/news/fullstory.php/aid/5702/Warning_over_wind_turbines_proposal.html

Muirake turbines - correction

In my post of Monday 6th September, I stated that the application for turbines at Muirake (just west of Cornhill) had been approved. As pointed out in a comment by CAWT admin, this is incorrect: they have only been recommended for approval by the local Area Committee. I reproduce the comment here, to make it more visible:

Muirake turbines have been recommended for approval by Banff & Buchan Council. As the Councillors have gone against the recommendation of the Planning Department, the proposal will be finally determined by Aberdeenshire Council Infrastructure Services Committee.

Committee Meeting Dates: http://tinyurl.com/2wlpm26

By contacting the Council in advance of the meeting, you can ask to make a representation regarding the plan. This will be your last opportunity to object to the Muirake proposal.

The ISC is separate to the Planning Committees. At a recent ISC meeting, plans for 3 x 92.5m turbines in Buchan were refused, despite Buchan Council recommending approval.

Good luck with your campaign!

These 2 giant turbines would be just 1.5 miles west of Cornhill, and 2.5 miles north east of Knock, interfering with the view of a treasured landmark. (The image in the post of 6/9/10, by the way, shows the view from Knock.)

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To join the CAWT email list (highly recommended!) send email to support@cawt.co.uk or telephone 01888 544432. CAWT (Concerned About Wind Turbines) is based at Cuminestown near Turriff. Cuminestown has the misfortune to be a sort of epicentre of wind-cluster development. CAWT has now widened its concern to all of Aberdeenshire.