How Much Power Will I Get From A Wind Turbine?



How Much Power Will I Get From A Wind Turbine?

You’ve checked your power bills for the last 12 months and know how much power you use. Your local power distribution company allows you to Net Meter, so you can produce power for a small wind turbine and just put it onto the grid, no expensive batteries and charge controllers. But you still haven’t answered that burning question: How much power will I get from the various sized small wind turbines that are available to me?

Factors to Consider When Calculating the Power Generated by a Small Wind Turbine:

  1. Local Regulations

    •  make sure you are allowed to put up a tower and wind turbine, before you purchase one. This not only includes the rules and regulations for your municipality, also talk to your neighbours!

  3. Site Location

    •  do you have access to “clear” wind. Can you put up a tower for a wind turbine that will be at lease 10 meters (30 feet) above nearby buildings and trees? Do you have space for Guy Wires.

  5. Average Wind Speed

    •  there are maps on the Internet that show you the average wind speed for your area. The good ones include wind speeds for a variety of heights above ground.  
    • this site contains wind speed information for Canada: and not only lets you zoom in on your location, but also provides a calculator that will tell you how much power you get from ANY sized wind turbine. After selecting your location, click on the Turbine Formula tab, input the turbine cut-in speed, maximum output and the wind speed required for the maximum output. The program then tells you how much power that turbine will generate over a one year period, at your location and for the height you selected.

  7. Wind Turbine Power Curve

    Ok, so you don’t live in Canada, but you did find a wind map for your location and you know the average wind speed for your site and height.

    All wind turbine manufactures provide a Power Curve (graph) though it may be called something slightly different, such as a Performance Graph or Power Output Graph. This graph will plot the power output, in watts or kilowatts, for various wind speeds. If the wind turbine you are looking at, does not have a power curve, I would stop looking immediately!

    Follow the axis that shows the wind speed, till you find your average wind speed. For London, the average wind speed is about 5.53 meters per second. On the first curve below, this turbine would generate about 40 watts per hour, at my location. Using the second curve, we can find our Monthly power output, would would be roughly 32.5 kilowatt/hours per month or around 390 kwh per year. By the way, these graphs are for an AirX wind turbine, which is about the smallest turbine available, and used on boats, remote cabins, etc. As a guideline, I've found that mosy small wind turbines tend to "average" about %10 of their "rated" power per hour. A small wind turbine that is rated at 400 watts, would produce an average of 40 watts per hour at my location.

    Note: power available in the wind, increases by a "cube" factor, as related to increases in wind speed. Thus if the wind speed doubles (2 times as much speed), the power available goes up by 2x2x2 = 8 times. If the wind speed triples, there is 3x3x3 = 27 times as much power in the wind. If you can find a really windy site, you'll get more power!

    AirX Power Curve

  8. Repeat Step 4 for Different Model Wind Turbines

    • Using the same average wind speed, plug the numbers into the Power Curves for the various wind turbines that are available in your local area.


These calculations will let you know how much power you can expect on average from a wind turbine. Of course there are local factors that can and will influence your actual results. What wind obstructions are nearby? Is the wind smooth or gusty? For small systems, most people will put up a turbine and measure the results over a year to see what they get. Large commercial wind turbines (wind farm size) will install a light-weight tower and special gauges to measure the actual wind speeds at the exact location and height where they hope to install their million dollar turbines. These test towers can cost around $30,000 each.



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