When studying this industry, understanding the different types of small wind turbines available on the market is essential. Wind turbines have two main designs which differ greatly in efficiency. The designs can be drag based or lift based. Drag based turbines are pushed by the wind and generate little energy. Lift based turbines use lift forces generated from a set of airfoil blades so it can generate two times more electricity.
A highly efficient lift based vertical axis wind turbine (VAWT) that can easily harness the wind, despite changing directions, without requiring a yawing mechanism. In urban and suburban environments this is a great advantage, given that the wind direction is highly variable due to its interaction with obstacles such as buildings and trees in its surroundings.
Its vertical configuration also allows it to be more adaptable to the urban setting as it can perform efficiently at lower rotational speeds and thus reduce vibrations and noise. Since the blades spin closely around the central shaft, another great benefit of this type of turbine is its compact design.
A drag based wind turbine that can extract less than half of the wind's power compared to other similarly-sized lift-based turbines. Since this type of turbine has low efficiency but offers high torque at low wind speeds, it is more suitable to pump water than to generate electricity.
A lift based wind turbine that is highly efficient in locations where the wind has a constant laminar flow. For this reason, this type of turbine is often found in wind farms where there is large open land. It needs a yawing mechanism to turn itself into the direction of the wind, thus will be less efficient in settings where the wind variability is high. The horizontal axis wind turbine requires the highest tip speed ratio to achieve high performance, thus it generally emits more noise and vibrations than vertical axis wind turbines.