Wind Energy Information
Ireland, Scotland and parts of the UK have the the best wind conditions in all of Europe.
Wind doesn’t simply push a turbine blade around in the way you might think – once it gets spinning, the blade works like a sail on a yacht, or a blade on an aircraft, creating lift. That’s why the blade tip often travels at six to eight times the wind speed.
Turbulence affects the areas of low and high pressure that cause this “lift” on a blade, and for this reasons, turbines generally perform very poorly in built-up areas.
But if you have a suitable site, wind is considerably more cost effective than solar photovoltaic cells for producing renewable electricity.
Wind speeds
In terms of turbines, wind speed is normally measured in metres per second. This is a conversion chart from the better known wind speed measurements:
| Wind Speed at 10m | Beaufort | Wind | |
| m/s | knots | ||
| 0.0 to 0.4 | 0.0 to 0.9 | 0 | Calm |
| 0.4 to 1.8 | 0.9 to 3.5 | 1 | Light |
| 1.8 to 3.6 | 3.5 to 7.0 | 2 | |
| 3.6 to 5.8 | 7 to 11 | 3 | |
| 5.8 to 8.5 | 11 to 17 | 4 | Moderate |
| 8.5 to 11 | 17 to 22 | 5 | Fresh |
| 11 to 14 | 22 to 28 | 6 | Strong |
| 14 to 17 | 28 to 34 | 7 | |
| 17 to 21 | 34 to 41 | 8 | Gale |
| 21 to 25 | 41 to 48 | 9 | |
| 25 to 29 | 48 to 56 | 10 | Strong Gale |
| 29 to 34 | 56 to 65 | 11 | |
| >34 | >65 | 12 | Hurricane |
Power in the wind
The power that a generator will produce is proportional to the wind speed cubed. If you double the wind speed, it will result in roughly an eight-fold increase in the amount of electricity produced. For that reason, even a small increase in average wind speed for a site can result in a lot of extra power.
It is important also to note that the average output of a wind turbine is not what it produces at its average wind speed. For example, if you have an average wind speed of 6 m/sec on your site, and a turbine that produces 400 watts at 6m/sec, that doesn’t mean that its average production will be 400 watts. This is because on occasions when the wind is above 6 m/sec, it produces a lot more power. For example at 12 m/sec, it will produce about 3,200 watts. For this reason, a number of calculations need to be made, bearing in mind the characteristics of the turbine, to assess the likely output for a given site.
This will depend on the mean wind speed at that site, the nature of the topography and local vegetation, obstacles upwind of the turbine etc.
You will find a comprehensive module on wind energy available on our Youtube channel (click here).
Note: All training material is provided in good faith to help you understand the principles of wind energy. The course is copyright and subject to out terms and conditions please revew the terms before watching the material.