Got a rural business in a windy spot?
A micro or small scale wind turbine could work if you meet these prerequisites:
- Relatively constant wind
- Average wind speed of 16 km/h (4.5 metres per second)
- Clear space away from obstructions like buildings or trees
- Backup for calm days – other generators in a grid-connected or stand-alone power system
There are two types of wind turbines
Horizontal-axis turbines are the most common. They’re mini-versions of the ones on commercial wind farms, with turbines are mounted on a tower facing the wind. They often have tail fins to make sure the blades constantly turn towards the wind.
Vertical-axis turbines work well where the wind direction varies quickly, because they don’t have to face the wind. Some are small enough to be mounted directly onto a building, others are mounted on a pole in the ground.
Households normally usually use micro wind turbines that are smaller than 5 kilowatts (kW). Small communities or groups of houses might use turbines up to 20 kW in size.
Energy output of small wind turbines
The amount of electricity a wind turbine generates depends on the wind speed and the turbine's capacity rating. If a model has a rated capacity of 1 kW, it will produce 1kWh of electricity per hour when exposed to a specified wind speed – generally 11-15 metres per second (40-55 km/h).
In reality, turbines usually generate only 10-40% of their rated capacity because wind speed goes up and down. So a 1 kW wind turbine might generate between 2.4 kWh and 9.6 kWh a day.
As you work out if a wind turbine is a cost-effective option for you, remember to factor in ongoing maintenance – which can be regularly needed if your turbine is on a very exposed site.