John Curtis kindly got his abacus out and did a bit of research. His figures are
illuminating and make interesting reading. Thanks John for letting me pass this on.
“I have been considering effects of parasitic power consumption by wind turbines, by which I mean power that they must use to stay functional even if there is no wind. The manufacturers do not give detailed information but I believe we can assess what is needed by using common sense.
Actual figures may vary from what I am assuming, but I do not think that I am far off. If you have any other ideas I would be very pleased to have them. Below is a representative list of equipment and systems that require electric power, together with assumed power consumptions.
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 –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.
What this says is that the turbine is virtually useless even at average wind speeds and that we need considerably more than average in order to get any useful power output. On average we can expect to power about 12 electric kettles. Not bad for an investment of around £2.4 million!!
Note that the turbine ‘sells’ its power based on metering at the output unit and thus avoids the effects of transmission losses. Also, there is no charge made for power that is consumed when there is low or no output. In other words, charges are made based in gross output, not net output.
And we do not even start to “save” CO2 emissions until we reach average wind speeds. What a huge con job is being foisted on us all.
Plus each turbine site requires cables to connect to a central control station from which the power is sent to the grid. There is a CO2 penalty that depends on installation size and length of power lines”
* Ed’s Note: As backup power needs to run 24/7 to compensate for the intermittancy of wind, in fact CO2 is not saved. In fact gas power stations running in standby mode perversely produce more CO2. RUK figures are based on replacement of energy from 2nd generation coal powered generating stations. 3rd generation black coal and the latest clean coal generators provide even less CO2. Readily available figures from the NETA website shows that wind is more likely to replace hydro (zero CO2), Nuclear(zero CO2) or Gas(50-70% less than coal). Coal runs as base load which wind will never be able to replace. On this basis the whole CO2 arguement for wind power is critically flawed. Apart from that, Carbon dioxide is not a pollutant. It is tasteless, colorless, nontoxic to humans at concentrations up to 13 times present levels and is essential to life. Plants breathe CO2, and as they grow and reproduce they exhale oxygen, making the earth habitable for humans. Instead of a disaster, the expected doubling of CO2 due to human activities will produce a number of benefits over the next century. Who’s afraid of CO2?
One interesting statistic that he has missed is that we are informed that power provided by the grid to maintain the turbines and in some cases to turn the blades to keep the oil moving is not charged to the operator. Multiply John’s figure by the amount of turbines installed and this is not an inconsiderable benefit to the wind farm companies.