While wind turbines are a fantastic means of capturing free energy there is the unfortunate reality that some sites are not suitable for the installation of a wind turbine system. A wind turbine in the wrong location would be similar to putting a solar panel in the shade; it will work a little bit but not very well.
Here are the two extremes of wind turbine sites:
Suitable site location:
A high elevation site with no surrounding obstructions.
Example: On top of a high hill with flat surroundings in all directions.
Unsuitable site location:
A low elevation with lots of surrounding obstructions.
Example: At the bottom of a valley surrounded by high trees.
Why are the above locations good and bad?
The wind travels faster at high altitude which means it carries more power. No surrounding obstructions mean that the wind is travelling with laminar air flow. The combination of fast winds and laminar air flow are good for wind turbines.
The wind travels slower at low altitudes which means it carries less power. The surrounding obstructions cause turbulent air flow. The combination of slow winds and turbulent air flow are bad for wind turbines.
To compare laminar and turbulent air flow imagine a river flowing with a nice flat water surface, the river then comes to a rocky rapid waterfall.
The rocks cause the nice flat water surface to be disturbed. This introduces water flow in all directions which creates whirlpools, vortices, peaks and troughs….etc.
For a wind turbine all the turbulence can cause excess stress on the wind turbine components and also reduces the amount of available power that can be extracted from the wind.
Every site is going to be different and that is why a site assessment should be carried out. The site assessment will determine if a wind turbine is suitable for the site. You can do an initial site assessment yourself and look out for the following things which will give you an initial indication of how suitable your site is for a wind turbine installation.
- High Elevation
- No obstructions in any direction
- Site close to where the power is to be used
- A large amount of surrounding land that you own
- Low Elevation *
- Obstructions in the way of the prevailing wind direction
- Hard access to the site or far from where the power is to be used
- Very little surrounding land
A site survey is the only sure way to know if a site is suitable or not. If required then a wind vane and anemometer can be placed at the site and the data recorded to give exact measurements of the wind speed and the prevailing wind direction at the site.
* Low Elevation is not always an issue. For example a wind turbine located at sea level on the coast will have a low elevation but would potentially still be a suitable site location. By low elevation we are usually referring to locations situated within an enclosed valley.