New Zealand has excellent wind resources and increasing numbers of wind farms have been proposed and built. Small scale and micro wind turbines are also available for homes, farms and businesses that want to generate their own wind power.
How wind turbines work
Wind turns the rotor blades of a turbine. The turbine then spins a shaft connected to a generator where electricity is generated. Wind turbines generate electricity as long as there is relatively constant wind at a reasonable speed. Most small wind turbines need an average speed of 4.5 metres per second (16 km/h).
Micro and small scale wind turbines are usually mounted on towers so they’re exposed to more consistent wind with a higher average speed. Because wind blows intermittently, small wind turbines are usually combined with other energy generators in a grid-connected or off-grid power system.
Types of wind turbines
Most wind turbines are horizontal-axis turbines - like the ones you see on wind farms. The turbines are mounted on a tower facing the wind. Small scale versions have tail fins to make sure the blades constantly turn towards the wind.
Vertical-axis turbines are less common than horizontal-axis turbines, but have the advantage of not needing to face the wind. This is useful where the wind direction varies quickly. Some are small enough to be mounted directly onto a building, others are mounted on a pole in the ground.
Rooftop or wall-mounted turbines
Rooftop or wall-mounted micro wind turbines are a new type of turbine.