Wind Maps or Pretty Pictures
/Would you bet thousands of dollars to make par in a game of golf without a putter?
Wind map is like a driver club in golf. It will get you near the hole. A putter, not unlike an anemometer, will get you in the hole and make you a winner.
Lets take a look why wind site surveys with anemometers are necessary to supplement your wind map data.
Wind maps are created from historical wind data collected from satellite imagery or at sparsely spaced measurement stations like airports and coastal observations stations. So unless you live at an airport or a coastal observation station, a wind map will be more of a rough guide line whether to even consider wind energy.
Hundreds of meters or yards above ground, wind is highly affected by local terrain, topography and vegetation and the highest Megawatt wind turbines barely reach over 200 meters. Most all residential scale wind turbines rarely reach above 50 m or 164 ft. The closer to the ground the wind is, the more it is effected and slowed down by the ground itself and whatever is growing or build upon it.
A wind survey performed at the height of your future wind turbine is in only accurate way to assess if it will perform as advertised. If you don’t have the capability or budget, then place an anemometer as high as you can and away from any objects like houses and trees. You can then extrapolate the increase in wind speed above your anemometer based on local surface features. Here is a tool to estimate wind speeds higher than your anemometer measurements: Vertical Wind Shear Profile Calculator
Remember: Using only a wind map to make you decisions about wind turbine placement is like shooting for a hole in one…and we all know how often that happens even in PGA golf tournaments.
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