Is my site windy enough?

Wind speed varies with time, from nothing on calm days to occasional violent gusts. If the wind speed at a site is recorded over a year, it will be seen to vary about a mean wind speed value. This is the annual mean wind speed (AMWS) and is an indication of how much wind energy is available. In the UK, AMWS could be as low as 4 m/s (9.0 mph) for an inland site to around 8 m/s (13 mph) or higher on the most exposed sites.

Once you have reviewed the information on this web site, please use our free windspeed checker, and receive our free Getting a Turbine guide, which will explain in the detail the whole process, and give you an indication of the costs and expected energy generation.

We can get a reasonable estimate of the wind speed of a site from its location. The UK Government funded a database (NOABL) gives an estimate of Annual Mean Wind Speeds (AMWS) in meters per second (m/s) for each 1km square all over the British Isles at heights of 10m, 25m and 45m above ground level.

Enter your post code in our free online Wind Speed Checker to see an estimate of the AMWS and estimated energy output, for a 1km square that includes your site.

Please note however that the wind speed checker only provides a very approximate method. The actual wind speed at your site will also be influenced by the local topography and any nearby obstructions such as trees, buildings etc. However, it will provide you with a useful indication of the possible energy capture from the wind turbine. Myriad CEG will advise you on the likely impact of your local conditions on your expected generation, but it can only ever be estimated and should not be treated as an exact prediction.

In general, you need an AMWS of at least 5 m/s to be able to generate a reasonable amount of energy, and ideally more than 5.5 m/s.

The turbines that Myriad CEG sell work well at low wind speeds, but because the energy available in the wind is a function of the cube of its speed, there is very little energy available to be harvested at wind speeds less than 4 m/s.

The height of the tower can also have a significant impact as described on our Which Tower FAQ page.

Seasonal Variations

Another thing to bear in mind is that there is normally more wind in the winter months than the summer ones. A wind turbine is therefore a very good match for heating and lighting requirements which are of course needed more in winter, but maybe not so well matched to air conditioning needs

The chart on the right gives an indication of how the amount of wind energy varies during the year at an average UK site, with typically 60% of the wind energy coming in the 6 months from October - March.

Wind Direction

In order for the turbine to be effective, it must have access to a good wind resource. This is one of the most difficult things to asses but in general the further away from buildings and trees, the better the average wind speed will be. This is especially true for any obstacles which are in a South West direction from the proposed turbine
location, as that is the most common direction the wind comes from in the UK.

Hills and Valleys

An important consideration is that of valleys and hills. Wind speeds up as it nears the top of a slope and slows down considerably on the other side of hill as it descends into the valley. The exact impact of this effect is very dependant upon the exact local conditions but this can have a dramatic effect on the energy that the wind turbine will generate.

Taking the impact of the wind direction as described above, you should avoid locating a wind turbine on the North East side of a hill.

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