Renewable Energy

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Wind Assessment Study and Calculator

These maps were generated as part of an Iowa Energy Center grant (Grant No. 93-04-02) to assess Iowa's wind resource. The Iowa Energy Center gratefully acknowledges the efforts of Tom Factor, Iowa Wind Energy Institute (IWEI) and Michael Brower, Brower & Company for their work in creating the maps.


This report was generated from the highest quality data available for Iowa and represents the most comprehensive and highest-quality data currently available for any state in the U.S.

1. The wind speeds listed for 2,000 cities in Iowa are based on a mapping process estimated to be within ±7% accuracy. This is due to the margins of error of the instruments used, the mapping techniques and the corrections for long-term averages. National Weather Service data indicates that the measured period (June 1994 - May 1996) was as much as 4% below the long term averages for parts of Iowa. The accuracy of monthly wind speeds is less than the accuracy of annual wind speeds, on the order of ±11%.

2. Local site characteristics such as obstructions (e.g., buildings, trees, etc.) can significantly affect the wind speed estimates. This report assumes that unobstructed sites will be used which are typical for the area listed. Obstructions can affect wind speeds at up to four times the height of the obstruction and as far away as a mile or more.

3. Turbine output estimates will vary more than the ±7% variability in the wind speeds. This is because small differences in wind speeds translate into large differences in turbine outputs.

4. It is highly recommended that a feasibility study be made of any site prior to installing a wind turbine. The feasibility study should include measuring actual wind speeds at the proposed turbine site for at least 3 months.

The Iowa Energy Center makes no guarantee as to the fitness of the maps and/or data contained on these pages for any intended purpose other than for general information. Use of the maps and/or data for any other purpose is solely at the risk of the user. The Iowa Energy Center and Iowa State University may not be held liable for any loss, damage or other consequence resulting from the use of the maps and/or data contained on these pages.

By clicking on the following link, the viewer agrees that he or she has read the caution statements above and agrees to the conditions regarding use of the data.

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