Wondering what a wind turbine Wind Class is? Well here you should be able to find a quick answer. This WTG (Wind Turbine Gnerator) classification tells you what kind of turbine fits the “normal wind conditions” in the location that you are planning to install the wind turbine / have a Wind Park. Studying the wind and Class of WTG is one of the most important features of a WTG that is considered while planning a wind park.
Categorization based on IEC Standard
Wind Class Categories are set by International Electrotechnical Commission (IEC) standard which is also shown in table below.
- High
- Medium
- Low
Wind class determine which turbine is suitable for the “normal wind conditions” of a particular area [1], which are typically drived by “Annual Average Wind Speed (Max)”, “Reference Wind Speed”, “50-year Return Gust” (speed of extreme gusts) and the size of turbulences in the wind park spot. These are measured usually at the turbine’s height [2].
IEC Wind-Class | |||
1 (High Wind) | 2 (Med. Wind) | 3 (Low Wind) | |
Reference Wind Speed | 50 m/s | 42.5 m/s | 7.5 m/s |
Annual Average Wind Speed (Max) | 10 m/s | 8.5 m/s | 7.5 m/s |
50-year Return Gust | 70m/s | 59.5 m/s | 52.5 m/s |
1-year Return Gust | 52.5 m/s | 44.6 m/s | 39.4 m/s |

Did you know?
Wind Edition publishes the trending top 10 Wind Turbine Generators article quarterly. In addition to that we also have an interactive map of all major offshore wind farms globally.
Our sister website, Solar Edition also publishes this trending article with new top 10 PV solar panels monthly since 2019.
Author: Shahab Moghadam
References
[1] IEC 61400, Wikipedia, URL: https://en.wikipedia.org/wiki/IEC_61400#:~:text=Wind%20classes%20determine%20which%20turbine,varies%20typically%20within%2010%20minutes.
[2] Effect of Wind Turbine Classes on the Electricity Production of Wind Farms in Cyprus Island, URL: https://www.hindawi.com/journals/cpis/2013/750958/