Vertical axis wind turbines and horizontal axis wind turbines are two types of wind turbines. These wind turbines can fulfill global electricity demand because Wind has the potential to generate more than enough electricity for humanity.
Vertical Axis Wind Turbines (VAWT)
VAWT is more efficient, cheaper, simpler, and easier to maintain as compared to HAWT because VAWT always faces the wind which is the inherited characters of the structure of this turbine. Following are some other advantages of VAWT.
Advantages of VAWT
- They are always facing the wind – no need for steering into the wind.
- Have greater surface area for energy capture – can be many times greater.
- Are more efficient in gusty winds – already facing the gust
- Can be installed in more locations – on roofs, along highways, in parking lots.
- Do not kill birds and wild – life – slow moving and highly visible.
- Can be scaled more easily – from milliwatts to megawatts.
- Can be significantly less expensive to build – are inherently simpler .
- Can have low maintenance downtime – mechanisms at or near ground level
- Produce less noise – low speed means less noise
- Are more esthetically pleasing – to some.
Horizontal Axis Wind Turbines (HAWT)
HAWT contains an electrical generator and rotor shaft at the top of a tower. It is important to build a tower because wings or blades of HAWT need relatively high-speed air to rotate. A gearbox is used to generate high speed rotation from slow moving blades. These high speed rotations are then used to generate electricity. These turbines have its own positives and negatives which are listed below.
- The pitch of the blades of these turbines can be adjusted according to the wind. It allows the turbine to rotate with the optimum speed and generate a maximum amount of electricity at any given instance.
- The towers of HAWTs can be used to generate higher power because after every 10 meter from the ground speed of wind increases 20% which can be used to increase power up to 34%.
- Blades of HWATs move perpendicular to the wind which allows them to generate electricity easily without any reciprocating action.
Following are some disadvantages of horizontal axis wind turbines.
- The transportation of this turbine sis very difficult especially turbines with 90-meter tower are very hard to move.
- The tall structure of these turbines can affect the various signals of different telecom companies.
- It requires very heavy and expensive gearbox, generator, and blades.
- Extra yaw control is required to turn blades in the direction of the wind.
- It also affects the beauty of landscape which is usually opposed by residents and public.