WindIQ Knowledge Center

Wind Industry Glossary

  

 Email Article  

Tweet  

  

• AEP: Annual energy production. Estimating how much energy a wind farm will produce is one of the drivers of wind project financing. Projecting a wind farm's AEP involves a thorough wind resource assessment.

• anemometer: An instrument used to measure wind speed. Shown is Second Wind's C3 anemometer. The cups catch the wind and cause the shaft to spin. The shaft is connected to a tiny electrical generator, and the wind speed is calculated as a function of the current produced by the spinning shaft.
• annual energy production: See AEP above.
• bistatic sodar: A sodar works by transmitting a pulse of acoustic energy, receiving the atmosphere echo of it, and calculating atmospheric measurements such as wind speed and direction from characteristics of the received echo. In a bistatic sodar, the transmitter (speakers) and receiver are separated from each other by a distance. In a monostatic sodar like Second Wind's Triton, the transmitters and receivers are the same speakers.
• CFD: See computational fluid dynamics.
• computational fluid dynamics (CFD): A branch of liquid mechanics that uses numerical methods and algorithms to analyze problems that involve fluid flows, such as wind moving over terrain and turbines. Used in the wind industry to model wind flow, aiding in wind resource assessment and forecasting.
• data logger: An electronic device such as the Nomad® 2 Wind Data Logger that records data over time or in relation to location, either with a built-in instrument or sensor or via external instruments and sensors.
• data recovery: The number of hours during which data were recorded by an instrument, divided by the total number of hours the instrument was operating. Data recovery is usually expressed as a percentage.
• Doppler shift: Also known as the "Doppler effect." A shift in frequency of a sound, light, or radio wave for an observer moving relative to the source of the wave. You can hear a Doppler shift when a police car passes with siren blaring -- it sounds higher as it comes towards you, and lower as it goes away from you. A Doppler sodar, lidar, or radar uses information gleaned from the Doppler shift in the echo of a wave to calculate information about the atmosphere.
• Doppler sodar: See Doppler shift above.
• forecasting: Predicting weather conditions; in the wind industry, near-term forecasting can help wind farm operators predict how much power will be available at a given time, aiding in grid management.
• gigawatt (GW):A unit of power equal to 1000 megawatts or one billion watts. Watts, gigawatts, and megawatts measure power, i.e., the rate at which energy is generated. For example, if a 100-Watt lightbulb is turned on for one hour, it uses 100 Watt-hours of energy. A kilowatt-hour is the amount of energy equivalent to a steady power of 1 kilowatt running for one hour.
• gin pole: A pole used to assist in raising a tilt-up tower. The gin pole is fixed at 90 degrees to the tower. The gin pole provides leverage in raising the tower, so that once the tower is upright, the gin pole is level with the ground.
• guy wire: Attaches a tower to a guy anchor and the ground.
• hub: The center of a wind generator rotor, which holds the blades in place and attaches to the shaft.
• hub height: The height of a wind generator's hub from the ground.
• lidar (light detection and ranging): A technology that uses light waves to measure atmospheric characteristics, including wind speed and direction. Lidar and sodar (sonic detection and ranging) are the two types of remote sensing systems used in the wind industry. See Doppler shift, above, for more information on how a lidar works.

• mesoscale wind map: A wind map simulating -- or modelling -- weather conditions for a representative meteorological year (366 days sampled from 15 years) on a horizontal grid of 2.5 km. Mesoscale maps use regional weather data, information about topographic and climatic conditions, and more. For more information see "How Wind Maps Are Created (And How Accurate Are They?)" (St. Francis University)
• meteorological tower, or met tower: A tall steel tubular or lattice tower on which anemometers, vanes, and other wind sensors are mounted to measure the wind at various heights.
• m/s: Meters per second, a common wind speed unit used in wind resource assessment.
• monostatic sodar: A sodar works by transmitting a pulse of acoustic energy, receiving the atmosphere echo of it, and calculating atmospheric measurements such as wind speed and direction from characteristics of the received echo. In a monostatic sodar like Second Wind's Triton, the transmitters and receivers are the same speakers.
• nacelle: The cover or housing for a wind turbine that holds all the turbine's generating components. The nacelle is at the hub of a turbine.
  
• nacelle anemometer: An anemometer mounted on the nacelle of a turbine, measuring wind speed as the turbine operates.
• nameplate capacity: The nameplate capacity of a wind turbine is the normal maximum output, typically expressed in megawatts (MW).
• net capacity factor: The ratio of the actual output of a power plant (in the wind industry, a wind farm) over a period of time and its potential output if it had operated at full nameplate capacity.
• O&M: Operations and maintenance.
• power curve: A data summary of the power characteristics of a wind turbine at various wind speeds. Turbine manufacturers specify a power curve with their turbines, but due to variations in terrain and wind behavior, a power curve of a wind turbine on a working wind farm will usually not be identical to the manufacturer's power curve. Power curve testing is normally done when a turbine is first installed (to compare the turbine's performance to the manufacturer's specified power curve) and may be done later on if the turbine's output is different from what the wind farm operator expects.

• remote sensing: In the wind industry, remote sensing refers to wind measurement technologies (sodar and lidar) that use sound or light waves to measure wind.
• sensor:  A device, such as an anemometer or wind vane, that responds to a signal or stimulus and produces an electrical signal that a data logger can monitor. Also called transducer. In the wind industry, sensors are used to measure wind speed, wind direction, or other atmospheric characteristics. Remote sensing systems such as sodar and lidar are also sometimes referred to as sensors.
• sodar (sonic detection and ranging): A technology that transmits a pulse of acoustic energy, receives the atmosphere echo of it, and calculates atmospheric measurements such as wind speed and direction from characteristics of the received echo. Second Wind's Triton is a sodar used in the commercial wind industry.

• tilt-up tower: A tower that is hinged at the base and secured with guy wires. The tower is erected by means of a gin pole and winch.
• wake effect: The effect on the wind resource downwind from a wind turbine. A turbine reduces the amount of wind energy available to turbines downwind, and also increases the amount of turbulence. Wake effects are one thing wind developers consider in spacing turbines.
• windmill: A machine which converts the energy of wind into rotational energy. Originally developed for milling grain for food production, windmills were also eventually used to pump water and generate electricity. When used to generate electricity they are more commonly known as wind turbines.

• wind prospecting: Also called scouting or site finding. The initial phase of wind farm development; scouting out good prospective locations for wind farms.
• wind resource assessment: Collection and analysis of wind data at a chosen location to determine its viability as a wind farm site.
• wind turbine: A wind-powered electrical generator.
• wind vane: Any device that mechanically turns in the direction of the wind. In data logging applications, wind vanes contain potentiometers or other sensors to provide an electrical signal proportional to wind direction.