Small Wind Energy Systems (Wind Turbines) contain electric generators that convert the power of the wind into clean, emissions-free power for individual homes, farms, and businesses. In most areas of the country small turbines may be suitable for owners with as little as one acre of land , and some designs may even be suitable for roof-mounting in certain urban environments.
Small wind turbines can be mounted on a tower to capture the most energy, or be roof mounted. At 80-100 feet (25-30 meters) or more above ground, wind turbines can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor.
The blades act much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make
Source: Department of Energy
Component : Wind Turbine
The turbine consists of 2-3 blades and the hub they are attached to
- Wind blowing over the blades turns them
The blades are turned out of the wind if the wind is blowing too hard or too softly; a brake stops them in an emergency
Blades are typically made of wood, PVC, aluminum, or fiberglass
- Horizontal-axis wind turbines (HAWT)
- Vertical-axis wind turbines (VAWT)
Horizontal-axis wind turbines (HAWT) :
Vertical-axis wind turbines (VAWT) :
- Most common type to turbines
- Have been mass produced for over 30 years
- Generally 3 blades on the turbine
- More efficient operation
Benefits of VAWTs :
- Developed within the past five years.
- Several unique designs and blade configurations.
Blade configurations are either Savonius (drag-type) or Darrieus (lift-type), or a combination of the two
Drawbacks of VAWTs:
Omnidirectional - Turnine does not need to change orientation to match the wind direction like HAWTs.
More durable and lower operating cost as it has fewer moving parts. Most are direct drive, i.e., no gearbox between the rotor and the generator)
More suitable for rooftop & urban installations. More efficient in turbulence
- Quieter operation & less vibration
- Compact design
- Can be installed at lower elevations
- Offer better aesthetics
- Less efficient power production
- May have trouble self starting at low wind speeds
Component : Inverter
Inverters convert DC electricity into AC (alternative current)
- Inverters have a 10-year warranty
Component : Mounting system
- Used to mount the solar panels on to the roof or the ground
- Pole mount
Recommended height of at least 26 ft, but ideally 20 ft above the highest object within 500 ft
In order to reduce vibrations and noise, and to ensure safety, it is important that wind turbines be installed well:
Turbine must be electrically grounded for safety from lightning bolts
Component : Monitoring device and service
Used by system owners to measure and track system performance
- Can access system production data over the web
- On-site monitoring
- Remote monitoring
- Additional cost to add a monitoring device and service
- Ensures the system is performing optimally
- Helps to quickly identify and correct performance issues
Tracking your performance, especially during the warranty period, ensures that you are optimizing your investment.