Wind Farms

  Wilham 13:04 09 Apr 06

In the recent thread 'No Oil?' click here
there was an assumption Wind Farms will increase in number. I oppose this view,- here rather than complicate hairyplum's interesting thread.

I find bob308w in FE's thread 'Do we get what we pay for?' click here objects to Wind Farms on the grounds the electicity generated is six times normal. I don't disagree, but my case is that full statistics will show wind farms to be a complete waste of public money.

Those aquainted with Queuing Theory and the work of A K Erlang (ca 1910) will instantly comprehend my argument, but those with no mathematical background will get the gist.

(i) Blackout calamity. A common 60W 240v lightbulb has a filament resistance of around 65 ohms. The power surge at switch-on is more than 10 times 60W. This property presents a major problem in restoring supply after a blackout.
(ii) Power Station Response Time. Gas, coal, nuclear generators meet control change v slowly. I asked the deputy manager of an 800MW (2x400's) gas power station the time taken to up the power of one of the pair from 100 to 300MW. He said it would be quicker to bring in the second from scratch to 200MW.
(iii) Spinning Reserve. Power is ever generated in excess of demand. Surplus is dispersed, nearly all under the sea. The safety margin used to be 27%. The three major blackouts in 2003 instigated international reviews of safety. Mary Fagin (S Telegraph 12/10/2003) records for London blackout the 17.7% safety margin had dropped from 25% two years earlier.
(iv) Wind Farms. Productive time is 30 to 40 %. Combine this info with above and the figures imply more power is wasted by wind farms than they generate to preserve safety level of spinning reserve.

  hzhzhz 13:09 09 Apr 06

Interesting stuff.

  hzhzhz 13:26 09 Apr 06
  hzhzhz 13:35 09 Apr 06

Am I right here?

When wind farms are supplying the grid, it means that the "conventional" generators are running for longer without producing electricity, therefore cancelling out,or almost, any benefit the wind farms could give.

  hzhzhz 13:38 09 Apr 06

They obviously have to keep the generators "spinning" in case the wind decides to stop blowing.

  Wilham 14:50 09 Apr 06

hzhzhz: A generator not spinning is a fish out of water. A better analogy is a large ship in dry dock,-it has to resist static gravitational stress. A generator rotor floats in liquid bearings,-rather like the platter in some recent HHD's, but here the rotor weighs 40 to 55 tonnes.

Generators spin continuously,.. min. used to be 3 to 4 years,- longer nowadays, I'm told.

I might add that they all spin at one speed only, - this is synchronous with the mains. Imagine in your car you try to maintain a constant speed when you come to a hill. Press RH pedal, car quickens, the slope slows you to the set speed. How would you manage if your speed couldn't vary at all? Oh, and if also you couldn't see the steepness ahead?

That's why I asked the time to change 1/4 to 3/4 power o/p.

  Wilham 14:58 09 Apr 06

Hard disk drives should be HDD's. Sorry.

Please answer the question "what causes asthma in children. Not passive smoking but diesel & petrol fumes a scientific fact so City/town people are prone to these effects. Conversely rural folk have to accept windfarms where they live simply despite the arguments listed above and not proven wind farms do reduce CO2 emmissions and do provide a contribution to cleaner productivity of electricity It can be said that nuclear is a clean provider but disposal is a problem for the waste products of nuclear.
The stand bye use of PCs is a contributer to 3rd world deprivation of power and more provision of co2

  Forum Editor 15:39 09 Apr 06

A bold assertion indeed, and one which some countries might find amusing. America, for instance, is investing billions of dollars in wind-farm technology, and if you go to California (as I did last year) you'll find that wind farm generation is certainly not considered a waste of money.

A few myths need dispelling, too.

1. "Wind farms only work part of the time"

Rarely, if ever, is the whole country completely calm. Our electricity system can cope with intermittent sources of energy, at levels of up to 10-15%, without operational changes. In the winter, when demand is greatest (and the weather is windiest), turbines operate at up to twice their summer output. Wind turbines are rarely out of service and have operating lives of up to 25 years.

2. "Wind Farms are inefficient"

With wind energy the fuel is free and so efficiency takes on a different meaning - there is no waste if some of the wind is not used. With coal and gas-fired power stations, much of the energy is lost as heat, which is exhausted to the atmosphere. Over the course of a year wind turbines will normally produce around 30% of their theoretical capacity. This is the average load factor, and should not be confused with efficiency.

3. "Wind farms still add to pollution"

Every unit of electricity produced by a wind turbine means at least half a kilogram less CO2 being emitted into the atmosphere. Denmark already produces more than 10% of its electricity needs from wind farms, avoiding the need to build further conventional, polluting power stations. Denmark plans to generate 50% of its electricity from wind by 2030, vastly reducing the country's contribution to global greenhouse gas emissions.

In the UK, we have the greatest wind resource of any European country. We know how to make large quantities of electricity from the wind. We should use that resource, and as I said in the previous thread on this subject, I believe we will. Europe certainly will, as will Australia, America, and South Africa. All these countries can't have got their sums wrong, surely?

  spuds 15:45 09 Apr 06

Our local school had a 'wind machine' installed, at great expense. Checking through the 'returns', it will take about 13 years to perhaps cover the initial costs, if all works to plan. In 13 years though, it could be assumed, maintenance and production methods will make this particular windmill obsolete, and a further burden on the schools already limited budget.

When it was first installed, that and the overhead police helicopter kept the kids amused.Who had got the biggest rota span-Will it take off!. Now both are just a passing consequence, and not worthy of a second glance.

  dewskit 16:47 09 Apr 06

I listened to an interesting discussion on this subject on Radio 4 sometime last week. It was suggested that the amount of CO2 generated in manufacturing the many tons of cement needed for the foundations of just one turbine, negates any saving for quite some years - food for thought?

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