Wind Turbine Glossary

  • Weibull Distribution: A usual distribution used to describe the wind variation for a typical site. This information can be used for estimating income from electricity generated and optimizing the design of the turbines.
  • Weak Grids: When the electrical grid with  low power-carrying ability. In this cases it may be necessary to reinforce the grid, in order to carry the fluctuating current from the wind turbine.
  • Off-peak Power: Off-peak Power refers to the electrcity that is generated during times where the demand (or load) on the system is low. If the amount of off-peak power generated exceeds the total load, smaller systems can store the excess in battery systems, or grid-tied systems can redirect the power to meet demand in other areas or displace other generation sources such as fossil fuel systems.
  • Horizontal axis wind turbine: It is the kind of turbine whose axis of rotation is horizontal. The blades are in a vertical plane.
  • Vertical axis wind turbine: The kind of wind turbine with a vertical axis of rotation.
  • Flicker: Flicker is an engineering expression for short lived voltage variations in the electrical grid which may cause light bulbs to flicker. It can happen if a wind turbine is connected to a weak grid, since short-lived wind variations will cause variations in power output.
  • interconnection: The physical connection of the electrical system of the Wind Energy system with the electrical system of the energy utility through which power may flow in either direction.
  • Windfarm: A windfarm is a series of multiple large wind turbines (typically 0.5-1 mW per turbine) which are built to generate electricity for utilities or multiple users.
  • Wind Resource: Wind resource refers to the availability and speed of the wind in a particular geographical area. The localized wind resource can vary significantly on a diurnal and seasonal basis. Wind resource atlases are available which can help predict the quality of the wind resource in a given area.
  • Swept area: The swept area of a horizontal axis wind turbine is the circular area defined by the rotation of the rotor blades, which is equal to pi multiplied by the square of the rotor blade length.
  • Anemometer: Device used to measure the wind speed at a site (cup-anemometer is frequent type).
  • Cut-In Wind Speed: The wind speed above which the wind turbine begins to produce power.
  • Cut-Out Wind Speed: The wind speed above which the wind turbine shuts itself down.
  • Diurnal Variation: Daily recurring patterns in wind speed and electrical demand.  Wind speed is typically higher during the day than at night, which corresponds with the typical electrical demand.
  • Nacelle: The streamlined housing of a wind turbine that typically encloses the generator and gearbox.
  • Rated Wind Speed: The wind speed at which the power produced is a maximum.
  • Standard Offer Contract:
  • An agreement that allows producers of alternative energy (wind, solar) to sell the energy to utilities at fixed rates.  This agreement allows project developers to plan with less financial risk.
  • Wake: A turbulent and slowed area of wind directly downstream of the wind turbine rotor (similar to the wake of a ship or large aircraft).
  • Gearbox: A device, located in the nacelle, used to increase the rotational speed of the shaft between the rotor and the generator.
  • Net Metering: A simplified method of metering the energy consumed and produced by utility customers who have their own renewable energy generator. It allows the customers to use there own electricity generation to offset their consumption over an agreed period and means that the customers can receive full retail price for all the electricity they produce. It is an important incentive for consumer investment in renewable technologies.
  • Off-grid: Wind energy systems not connected to the utility grid. They are usually appropriate for power needs that are far from the nearest utility grid. They can be for remote villages, islands, resorts, farms, homes and cottages, telecommunications and monitoring equipment, navigation aids and water pumps. They can usually be more advantageous when implemented as a hybrid wind energy system.
  • Rotor: The component of a wind turbine that captures, with its blades, the energy from the wind and converts it into mechanical energy onto the rotor shaft or hub.

Please visit also the Danish Wind Industry Association to view an excellent wind glossary.