Readers letters
Engineers must become data based about wind energy. The myths surrounding its contribution have to be scotched. There is an excellent report contained in “Analysis of UK Wind Power Generation” by Stuart Young Consulting, commissioned by the John Muir Trust. The data source is the National Grid which records electrical power generated every 5 minutes, the basis for payment to wind farm operators. Use Google and read it for yourself.
The analysis is very detailed and shows that in the period from Nov 2008 until Dec 2010 wind power generation was below 20% of capacity for more than half the time. The extremes are revealing, at 03:00 on 28-03-11 the entire output from 3226 MW installed capacity was 9MW, three days later at 11:40 the output was 2618MW, the highest ever recorded. So discussion about energy balance and availability efficiencies (September Letters) are pretty meaningless in the face of such wild swings in output.
One must read the report to fully appreciate how using average wind speed to infer average power output has been very misleading, the instantaneous values are what really matter. The assumptions that periods of high pressure are confined to summer and that the wind is always blowing somewhere in the UK are wrong, high barometric pressure and low or no wind can occur at any time over the whole of the UK.
In the county of Northamptonshire there are planning applications in place for no less than 53 separate windmills out of a total of 94 new windmills currently projected for the UK. Why? Well Northants does not have any areas of outstanding natural beauty, national parks, big cities or major airports which makes it relatively plain sailing for wind farm developers to defeat local concerned groups. It also has relatively low wind speeds, about 6m/s but that doesn’t stop the use of average values hoodwinking the gullible into believing some inflated projections for electrical energy production. I make no apology for not using the noun turbine, that implies continuous output, a wild dream when it comes to wind farms.
During the industrial revolution when the steam engine and electrical power generation appeared local cereal millers became less cost effective and went out of business because their windmills were an unreliable source of power, nothing has changed. But there is one exception, 100% subsidy for on shore and 200% subsidy for off shore, making it an easy source of income whilst the back up of conventional power stations will still be needed to avoid blackouts as the 30 TW renewables target is approached by 2030, absolute madness.
It is time for the professional engineering institutions to become more vocal about the real performance of wind farms and to actively support the nuclear option for base load generation.
I have no connection with Stuart Young Consulting.
Tony Lake
Next letter: British Rail is best forgotten