Wind power classes
The term "wind power classes" is a standard instrument for determining the suitability of a location for wind farm development. Wind power density is measured in watts per square meter and indicates how much energy is available at the site for conversion by a wind turbine.
As shown in the following table, there are seven wind power classes (1 through 7). It is standard to give wind density measurement at both 10 meter and 50 meter heights. Wind Power Class number increases with an increase of wind density. Thus class 7 sites have the highest wind density.
| Wind Power Class | 10 meter | 50 meter | ||
|---|---|---|---|---|
| Wind Power density | Speed m/s (mph) |
Wind Power Density | Wind Speed m/s (mph) | |
| 1 | 0 | 0 | 0 | 0 |
| 2 | 100 - 150 | 4.4 (9.8) / 5.11 (11.5) | 200 - 300 | 5.6 (12.5) / 6.4 (14.3) |
| 3 | 150 - 200 | 5.1 (11.5) / 5.6 (12.5) | 300 - 400 | 6.4 (14.3) / 7.0 (15.7) |
| 4 | 200 - 250 | 5.6 (12.5) / 6.0 (13.4) | 400 - 500 | 7.0 (15.7) / (16.8) |
| 5 | 250 - 300 | 6.0 (13.4)/6.4 (14.3) | 500 - 600 | 7.5 (16.8)/8.0 (17.9) |
| 6 | 300 - 400 | 6.4 (14.3)/7.0 (15.7) | 600 - 800 | 8.0 (17.9)/8.8 (19.7) |
| 7 | >400 | >7.0 (15.7) | >800 | >8.8 (19.7)
|
Given the present state of wind turbine technology, areas designated class 4 or greater are suitable for most utility-scale wind turbine applications. The National Renewable Energy Laboratory and Wind Powering America are working with industry partners to make class 3 sites available for utility scale development. Class 2 areas are marginal for utility-scale applications but may be suitable for small wind projects. Class 1 areas are generally not suitable for wind power development. [2]
