Sunday, 21 October 2012

Wind power? Not quite.

Although I knew the basics the details were very hard to find in one place online, so someone on my Facebook group did the full accounts so the total can be easily shown to demonstrate wind turbines use as much power as they create, ie they do not do anything at all.
Yaw mechanism to turn the rotor into the wind. 20kW
Pitch mechanism to adjust the blade angle to the wind 15kW
Lights, controllers, communication, sensors, data collection, etc. 10kW
Heating the blades during winter. 250Kw
Heating/cooling and dehumidifying the nacelle. 10kW
Oil heater, pump, cooler and filtering system of the gearbox 25kW
Hydraulic brake to lock the blades when the wind is too strong. 5kW
Thyristors for power conditioning and connection. 25kW
Magnetizing the stator to keep the rotor speed constant 25kW
Using the generator as a motor to help blades start to turn when wind speed is low or, as many suspect, to create the illusion the facility is producing electricity when it is not, particularly during site tours. It also spins the rotor shaft and blades to prevent warping when there is no wind. 50Kw. 
TOTAL Installed. 435kW.
Not all items will be used at the same time, although they may be. However, we can generously assume 50% usage, for a parasitic consumption of approximately 215 kW.

Turbine rated wind speed is 12 mps. Cut in speed is 4 mps. Rated power is 2 mW. Power varies as cube of wind speed.
Therefore Power at 4mps is 2,000,000/3x3x3 = 74kW 
Nett output is รข??141kW
Power at 5mps is 144kW Nett output is -71kW
Power at 6mps is 250kW 
Nett output is +35kW
This shows that the machine does not start to produce useful power until wind speeds reach around 6mps, assuming that 35kW from a 2mW machine can be considered as useful. 
Published figures for average wind speeds locally (Banbury area. It will vary depending on actual location) at masthead height are 6mps. 
There are subsequent losses such as transformer inefficiencies and transmission losses to take power from turbine to grid. We can assume approximately 6% to 15%, depending on the type of equipment and transmission line lengths.


Add to that the additional costs of feed in tariffs, guaranteed profits for land rental (including by the British Royal Family, whose leaked correspondence showed they had changed their position on them once they were offered this deal on their own land), and compensation payments for each 'off' day. That sends it well into the red and without said subsidies wind farms simply wouldn't exist in the first place, as all they actually do is redistribute cash mainly on government orders.

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