As an electricity supply professional, I would take issue with Terry Duffin on a number of points, letter 10/10/10. He is clearly not in the business.
While the average UK home does use about 4,500KWh pa, the UK maximum demand, circa 60 million KW, is a little over 2KW per dwelling. That total includes Power supplied to workplaces, hospitals, street lighting… all needed by the average home. The maximum demand must be met, or blackouts result.
Our control engineers always load subsidised wind machines to the maximum that meteorology will allow, government rules. Then comes UK nuclear, over 8,000MW, 93% of its full load, 24/7, now that the summer maintenance period is over.
Then comes French nuclear – very little in the anticyclone that has been here for the last week or so, when Denmark’s 3,500MW of windpower has been below 50MW, and Germany’s 25,000MW will be suffering similarly. I expect they outbid us in the market.
So on Wednesday, in the small hours, while our wind fleet was scoring 5% of its capacity, we were burning 8,500MW of coal. That could have been reduced by perhaps 2,000MW, if the pumps recharging storage hydro had been turned off. National Grid and NETA data enables determination of efficiency of the pumping cycle, about 72%-75%. So it is the most polluting electricity we have. Stored electricity always is.
Terry Duffin mentions the 2008(!) incident. Longannet p/station had been shut down for some time for major re-furbishment, and had just re-commissioned one machine. The load had built up to about 350MW when it tripped. Sizewell, 1,320MW, tripped almost immediately. Clearly something, people or equipment, had malfunctioned. Supplies were restored in 40 minutes, because all the others kept running.
In contrast, from midnight 9th Oct until now, 7pm 17th, the UK wind fleet has been below average for 82% of the time, with a low point of 3%. Studies in previous winters have often shown such scores.
Conventional Power stations are mutually supporting. Wind turbines are not, and solar always fails completely at sunset.
The “full statistical analysis” Terry Duffin mentions, sounds like the Environmental Change Institute, University of Oxford, (copy, free +44 (0)1865 275 838), “average winds are stronger in winter” When considering reliability, it’s the lowest Power that counts, not average.
The ECI quotes the Nordex brochure: their 2,500KW machine generates zero in winds below 4m/sec, so “all hours where winds are below this speed are included in the 32definition of low wind speed conditions”. Why does the author use four words to define a two word description?
The ECI says, “there was not a single hour in the study period when wind speeds at every location were below 4m/sec”, ie, there was at least one UK location where wind was perhaps at 4m/sec producing 15KW. Big deal.
The report adds, “On average there is around one hour per year when over 90% of the UK experiences low wind speed conditions”. We know that wind power across the UK has an annual average Load Factor of 25%. It is an arithmetical certainty that there will be more hours when winds are below average than above.
And what of the overall situation when 50% of wind turbines are producing zero? What will the other 50% be producing? Have a guess.
The author, Graham Sinden, was the expert witness when the House of Lords Select Committee questioned ECI on its evidence about wind Power. www.parliament.the-stationery-office.co.uk/pa/ld200304/ldselect/ldsctech/999/4021103.htm Baroness Platt asked, Q139, “What about a stationary anticyclone in the middle of winter over the British Isles?” The author replied, “We have looked at that occurring in the wind data and the wind data does not show it.”
He was correct, stationary means not moving at all: but in the context of windmills and 4m/sec winds… His letter published in the FT repeats his opinion, “calm UK weather is a myth”. True, if “calm” means wind at 0.0m/sec, everywhere.
Wind, waves and solar run out of “fuel” when Nature decides. If supplies of gas are cut off, we would run out in a matter of weeks.
Nuclear fuel is a little different. In successive generations of reactor development the amount of uranium required for one years supply to an average home has dropped from about 45 grams to about 3 grams. Further, the “waste” from the earlier reactors contains the uranium they failed to burn. Sir David King, previously Government Chief Scientist estimates that we have enough in store to last until 2060. Should we build fast reactors, it will stretch to 2100.
There is more, but this is already too long.
Bill Hyde, Offham, Kent