Second Wind Knowledge Center
Wind Energy Glossary

Annual Energy Production

Above Ground Level

Above Mean Sea Level

An instrument used to measure wind velocity or wind speed.

Automated Surface Observing System

Balance of Plant

Cost of Energy

Capacity Factor

Computational Fluid Dynamics

An electronic device such as Nomad 2 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 hours divided by report period hours expressed as a percent.

Digital Elevation Model

A shift in frequency and wave length of a sound wave, used in reference to the characteristics of the return echo.

Digital Terrain Model

A software method of detecting and eliminating fixed echoes when processing sodar data.

An echo returned from a fixed object. Fixed echoes may cause distorted sodar readings.

Using observed weather data and wind farm operational data to predict future wind energy output for the next few minutes, the next hour, the next day, or the next few days.

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.

Attaches a tower to a guy anchor and the ground.

Gigawatt

Gigawatt hour

The center of a wind generator rotor, which holds the blades in place and attaches to the shaft.

International Electrotechnical Commission

Investment Tax Credit

Kilowatt

Kilowatt hour

Steel framework tower usually triangular or square in cross-section. Lattice towers may be self-supporting or guyed.

Light Detection and Ranging

Meters per second

Measure Correlate Predict

Meteorological Tower

Megawatt

Megawatt hour

Using computer-based weather and wind simulations to produce high-resolution wind speed and direction data to determine project feasibility.

North American Regional Re-analysis

Net Capacity Factor

Operations and Maintenance

50% Probability of Exceedence

90% Probability of Exceedence

Power Curve

A data summary that characterizes wind turbine performance as the average power produced at a range of wind speeds.

A more detailed look at various locations within a likely wind-farm site to determine ideal turbine placement.

Production Tax Credit

Radio Detection and Ranging

The maximum electric power output at which the turbine manufacturer rates the turbine.

Roughness Index

Wind Resource File

Supervisory Control And Data Acquisition. A system that provides performance information and control over a group of devices, such as wind turbines.

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.

A resistor used to convert current into voltage.

Sonic detection and ranging. Triton is a type of sodar.

Tabular Wind Frequency Distribution

Turbulence Intensity

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.

Structure upon which anemometers or other meteorological equipment are mounted.

Second Wind's sonic wind profiler, a ground-based remote sensing system that measures wind up to 200 meters.

A tower composed of one or more steel cylinders. A tubular tower may be guyed or self-supporting. Commonly the diameter increases toward the base for increased strength.

See Wind Vane.

Long-term collection of wind data across a general area to determine its viability as a wind farm site.

Another term for wind direction distribution. The term "wind rose" comes from a circular graphic representation of the distribution, which might resemble a flower.

A difference in wind speed or direction at different heights. Wind shear is usually used to refer to a difference in wind speed, and wind direction shear or wind veer is used to refer to a difference in wind direction.

The average horizontal speed of the wind at any given altitude as measured by Triton.

A data summary that indicates the amount or percent of time the wind blows over a range of wind speeds.

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.

A difference in wind direction at different heights. Also referred to as "wind direction shear."

Wind Resource Assessment

Wind Resource Grid

Wind Turbine/Generator