What parameters define a small wind turbine?

A small wind turbine, irregardless of its class, will consist of the following:
  • 2 or 3 blades
  • Nacelle with 1 or 2 generators
  • Tower
  • Control electronics
The larger the blades, the better it is. They are defined either by blade length (usually not more than 10 m), rotor diameter (up to 22-23 m) or swept area (rarely above 300 m2). Blades should be compared between generators of the same power (a 10 kW generator with a 5 m blade will produce more energy than a 10 kW generator with a 3.5 m blade). However, larger blades mean that the turbine is more expensive.

Nacelle is the "head" of a small wind turbine and houses the generator. The size of the generator depends on its power rating in kW, which rarely exceeds 100 kW. A small household will usually have a 10-20 kW generator, while a 50 kW generator allows to sell excessive energy to the grid.

The tower is made of steel and can be either a tubular or lattice towers. Lattice towers and tubular towers starting from 30 kW will require a large crane for installation; if a tower has a hydraulic tilt-up, only a small crane or an excavator is required and maintenance is easier. Towers are usually from 18 to 36 m high (higher is better).

Continue reading to know about what to look for in a good wind turbine.