Most people wonder how much power a wind turbine can produce, and never stop to wonder how much power a wind turbine requires to operate. Mechanical engineer Jerry Graf believes that it is long past time for people to ask that question:
Big turbines often incorporate rechargeable batteries or ultracapacitors to power their own electrical systems. When those get depleted, the power must come from the grid. This power goes into running equipment such as yaw mechanisms that keep the blades turned into the wind; blade-pitch controls that meter the spinning rotor; aircraft lights and data-collection electronics; oil heaters, pumps, and coolers for the multi-ton gearbox; and hydraulic brakes for locking blades down in high winds.
Turbines in northern climes also need blade heaters to prevent icing. Reports I’ve seen say these heaters can consume up to 20% of a turbine’s rated power output. Many big turbines also need dehumidifiers and heaters in their nacelles. And until recently, large turbines employed doubly-fed induction generators that bleed power from the grid to create their magnetic fields. (It should be said, though, that designs now on the drawing boards use permanent magnets instead.)
Instances of low or no wind pose another problem. Large turbines may need to use their generators as motors to help get the blades turning. And some wind skeptics have posed a question about the direct-drive turbines now emerging from the labs: Large ships frequently must expend energy to slowly turn their heavy driveshafts when at port to prevent them from sagging. Could the same be said of these superlarge wind turbines?
Wind-farm operators don’t say much about turbine-power demands. Typically, turbine-power consumption is one of the factors that gets lumped into a wind-farm’s operation and maintenance costs. I’ve never found either a wind-farm operator or a wind-turbine maker willing to discuss these costs. It would not be much of an exaggeration to say the wind industry treats such information as a state secret. _MachineDesign
There are too many aspects to the operation of big wind farms which are treated as state secrets. No wonder the O-P reich promotes wind power so heavily. Politicians are no doubt attracted to the "all image and no substance" aspects of big wind power.
By. Al Fin.
I can for example report that for it's third year of operation (2008) the 90MW (nameplate capacity) offshore wind off the North Kent coast (East UK), imported 603MWh of electricity. This, we are told by the industry, enough to power 128 British homes for a year. However, during the same year, this power station exported 265,139MWh.
Whether this generated electricity was in fact dispatchable when it it was required is another argument.
In assessing this, I first read through critiques of wind energy to determine if any quantitative work had been done. I found one site that is used as the source of misleading statements regarding consumption of electricity by wind turbines by anti-wind advocate Eric Rosenbloom. Other anti-wind advocacy sites referenced Mr. Rosenbloom's AWEO site uncritically and did not add any substantiation. Mr. Rosenbloom's sources are an unnamed Swedish graduate student on a defunct discussion forum and unlisted personal correspondence.
On the other hand, wind turbine producers have a vested interest in full lifecycle cost assessments and publish these. For example, I will use material from Vesta, on their LCA for their 3.0MW onshore and offshore wind turbines. This and other LCAs are published and available. These LCAs following manufacturing standard ISO 14040-14043 approaches to costing and are independently reviewed by Force Technology, a firm engaged for that purpose by Vesta.
Electrical consumption during operation is not listed, although every other form of energy during manufacturing, construction, use and decomissioning is listed. That's not because they are hiding it, it's because it doesn't exist.
References, analysis, excerpts and an interesting graphic are here.
http://www.quora.com/What-is-the-ratio-of-consumption-to-production-on-an-average-windmill-over-the-course-of-a-year
Wind is intermittent, seasonal and another important point that much of the power is lost as it travels along the transmission lines.
The companies also don't account for the drag on the turbine blades with all the dead birds and bats stuck to them.
No one is saying that the net output of a turbine is zero, but just be honest with people/taxpayers as to all the factors that go into this energy source. I wonder what the ROI is for some turbines I've seen that never seem to be rotating....