On Fri, 6 Oct 2006 12:27:59 +0100 someone who may be " cupra" wrote this:-
Operating wind turbines on land was essential during the early days. It was the only way to develop the engineering expertise. However, engineering has now developed to the stage where offshore wind farms are possible. The foundations, grid connection and maintenance are all more expensive. So are the turbines, for example they need pressurised nacelles to keep the salt out. Against this wind conditions are better and it is easier to get permission for larger turbines. The results from some of the first offshore wind farms have been mixed, but it is early days.
The whole basis of the design of Dinorwig, designed in the late
60's/early 70's was to cater for the simultaneous failure of the two largest single generators (not power stations) on the UK grid system or for the failure of a double circuit 400kV line (with the conductors available at the time) the former is 1320MW (2 x 660MW), the later around about 1800MW.
That Dinorwig can generate pretty close to the latter figure starting from the units "spinning in air" to full load in around 15 seconds means it will always play a very important part in ensuring system stability.
That's as maybe but junking existing generating capacity in order to build new wind capacity of at least 3.3 times the nominal capacity to replace it and on top of that 90% new back up capacity doesn't make sense.
The message from David Hansen contains these words:
The only thing I can find is the vague statement that there has always been some wind somewhere in the UK and that not even qualified by being enough wind to persuade a wind turbine to generate any electricity. If the whole of the UKs wind industry on average only produces 27% - 30% of rated output there must be considerable periods when it is producing markedly less than average.
More exaggeration.
Direct line to every power station in the country, I don't think so. All Dinorwig can do is supply the grid.
You moved the goal posts, I just moved them back to where they were, but it doesn't take a genius to come up with a scenario where a whole power station has to be taken off line.
The message from David Hansen contains these words:
Where do you get your figures from? I came across a claim that as recently as 2004 nuclear accounted for 44% of generation in Scotland and another by a politician that in 2006 it amounted to over 50%.
No, individual "shop floor" workers have little or no say in the policies or direction of the company they work for. Only The Board has that power and they act to protect their own interests and share holding(s) in the company.
That's not a bath! Hand washing isn't always very effective, I grant you.
I believe they do but I couldn't walk to the nearest carrying my load and if I drove it would be polluting and difficult to park and I don't want to waste the time sitting in a place like that or makinig two journeys. I prefer to be at home, where I can be served with drinks, have the telephone to hand and listen to the radio. I also end up with beautifully soft feet :-)
There's also the cost element for those who care. The water was heated by yesterday's sun, I didn't need to hand over any cash as I would in a laundrette.
Weren't we discussing the unsightliness (or otherwise) of wind farms? Surely nearly everyone has seen one or more of these now so will not be using hearsay.
On 06 Oct 2006 14:31:44 GMT someone who may be snipped-for-privacy@isbd.co.uk wrote this:-
A month or so ago I went on a journey by train from the Central Belt of Scotland to the South Coast of England. Judging by the postings of the anti-wind lobby I should have seen wind turbines on just about every peak and hillside.
In fact I saw a number of things on peaks and hillsides. Electricity pylons and telecommunications masts of various sorts. I only saw two wind farms though. One can see the top third or so of some of the blades at Black Law when the train is near Carstairs and most of the small wind farm near Lancaster. From this I suspect that nearly everyone has not seen a wind farm.
The research shows that it is when people do see wind farms and turbines and in the flesh that most of those who previously had objections drop them. The SDC report on wind energy has a number of references, should anyone wish to take them up.
The British Wind Energy Association, not exactly an unbiased source. B-)
That quote is out of context and, IMHO, his work has technical flaws.
At the bottom of the page you reference there is a link to the "Technical Annex" which should be read. A major assumption is made about how low frequency noise affects the human body basically if you can't hear it (with your ears) it doesn't affect you. Thus most of the figures quoted use the "A" weighting(*) on the sound level meter to mimic the human ears response. There needs to be serious and extensive research either using the G weighting or preferably flat down to some fraction of a Hz.
Leventhall 2004
Dr Geoff Leventhall, Consultant in Noise Vibration and Acoustics and author of the Defra Report on Low Frequency Noise and its Effects, predicted levels at a proposed wind farm using a calibrated tape recording of noise from a 1.3 megawatt (MW) wind turbine. The tape was analysed in order to investigate any presence of low frequency noise.
Leventhall's analysis confirmed the presence of tonal peaks in the low frequency region. However, their levels were found to be below the hearing threshold of most people, and therefore the research concluded that noise from the proposed wind farm installation in the low frequency (10Hz to 200Hz) range was unlikely to be a problem.
In fact, Dr Leventhall has since said in personal communication that "I can state quite categorically that there is no significant infrasound from current designs of wind turbines. To say that there is an infrasound problem is one of the hares which objectors to wind farms like to run. There will not be any effects from infrasound from the turbines."
The turbines produce a modulated higher frequency - the swish, swish - which people may not like, but this is not infrasound. There is no low frequency in it. There is negligible infrasound and very little low frequency noise from wind turbines - a few low level tones from the gearbox. Whatever might be making people ill it is not low frequency noise - there just isn't enough of it from modern wind turbines.
Note:
The quote you use is in a "personal communication" rather than in any official report.
Dr Leventhall also only analysed a tape recording rather than doing any real field work. How was this recording made? What limitations are inherent in the recording equipment or technique? Is it a single recording or a collection of recordings made under varying wind conditions and locations relative to the turbines?
Dr Leventhall's analysis only covered the band 10Hz to 200Hz. What about sounds below 10Hz?
(*) "A" weighting reduces the signal level such that at 10Hz it is 70dB below the *actual* environmental level. A 70dB level reduction is enough to make a pneumatic drill barely audible.
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