Thursday, August 19, 2010

How Much Power Does it Take to Run a Wind Turbine?

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.

More bad news about big wind



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