A (10) | B (1) | C (9) | D (15) | E (8) | F (3) | G (5) | H (3) | I (8) | K (2) | L (4) | M (11) | N (6) | O (3) | P (16) | R (6) | S (10) | T (5) | U (1) | W (6) | Z (1)
Term Definition
Wake Losses

The space behind a wind turbine that is marked by decreased wind power capacity due to the fact that the turbine itself used the energy in turning the blades. The wind behind the turbine, in its wake, is less effective at generating energy for a certain distance in the downwind direction due to turbulence created by the upwind machine. Thus, when siting a wind farm, it is important to space turbines as to minimize the impact each has on the others’ power production capacity, taking into account additional costs for laying of electrical cable and other infrastructure required when machines are spaced further apart.


A unit of electrical power: 1/1000 kW


Transmitting bulk electricity from a generating plant to a distribution system across a third party's lines.

Wind Power Class

A way of quantifying on a scale the strength of the wind at a project site. The Department of Energy’s National Renewable Energy Laboratory defines the wind class at a site on a scale from 1 to 7 (1 being low and 7 being high) based on average wind speed and power density to offer guidance to potential developers as to where wind projects might be feasible.

Wind Rose

A wind rose shows the direction and the frequency of that direction that the wind blows at a particular location. Wind roses are used in wind projects to portray the amount of energy that comes into the wind project from various directions.

Wind Shear

A term and calculation used to describe how wind speed increases with height above the surface of the earth. The degree of wind shear is a factor of the complexity of the terrain as well as the actual heights measured. Wind shear increases as friction between the wind and the ground becomes greater. Wind shear is not a measure of the wind speed at a site. It is an extrapolation of the difference in wind speed between two different heights above the ground. Thus, high wind shear at a site does not necessarily mean high wind speeds at the site.