Types of Wind Turbines
The most commonly used type of wind turbine today is the horizontal-axis wind turbine.
In a HAWT the axis of the rotating turbine is horizontal, or parallel to the ground, and it is the type of wind turbine that one would usually see on a wind farm.
The vertical axis wind turbine has an axis of rotation that is perpendicular to the ground.
Be careful to not confuse a windmill with a wind turbine. A windmill is commonly used for grinding grains or pumping water.
A windmill does not produce electricity. If you attach a turbine generator to a windmill, then it is no longer called a windmill, it becomes a wind turbine.
Horizontal Axis Wind Turbines differ from the vertical axis turbine in a few different ways:
1 – The nose of the turbine must be facing the wind for the rotor to spin. There is usually a built in yaw mechanism and wind vane for automated directional movement of the turbine towards the wind.
2 – They perform worse in extreme wind conditions (have lower furling wind speeds) and are often shut off at high wind speeds to prevent damage to the turbine and it’s components.
3 – They are constructed higher into the air, giving them access to stronger winds, but maintenance of the machine and it’s components is not easily accessible.
4 – The HAWT produces more energy at normal wind speeds than a vertical axis system. Depending on the systems, they could produce 20% – 40% more electrical output than a vertical turbine.
5 – They usually take up less ground space for construction, but they do often require long cables or tall lattice tower systems for support.
A horizontal axis wind turbine is the type of wind turbine that is used most often because it produces more electrical output, is more technologically advanced, and more readily available in today’s marketplace than the vertical system.
Vertical Axis Wind Turbines differ from their counterpart in a few different ways:
1 – They are constructed low to the ground, which is a disadvantage because wind speeds are lower closer to the ground, but it is also an advantage because the mechanical components of the generator are easier to access for maintenance.
2 – They can collect the wind from any direction, thus not requiring a yaw mechanism to control movement.
3 – They are able to perform in high and extreme wind speeds, which is why you sometimes see vertical axis wind turbines on high mountains or near cliffs where wind speeds can be dangerously high.
4 – They produce energy much less efficiently than their counterpart the horizontal axis turbine.
The VAWT is the type of wind turbine that is much less efficient, not as commonly used, and is not as readily available on the market compared to the horizontal turbine. However, each type of wind turbine does have its own advantages and disadvantages.