Wind Power

From Wind wiki

The wind power available in the wind can be derived directly from the kinetic energy calculations (See Kinetic Energy). We will begin with the equation for kinetic energy, E_t:

E_t=1/2 ρv^3 At

, where ρ is the density of the air mass, v is the velocity of the air mass, and A is the area of the cross-section of the air mass.

Power is the rate at which energy is transmitted, or the amount of energy required for a given unit of time. Thus, to derive the power P_wind from our kinetic energy equation, we divide the kinetic energy by the unit time, t:

P_wind=E_t/t=1/2 ρv^3 A

A commonly used calculation is the wind power density (WPD). This relates the power available per unit area. Essentially it is a way of calculating the power that is available in a specified location. Generally, the WPD is indicated with a height that indicates at what level the measurements are taken. The derivation for the WPD is given by:

WPD=P_wind/A=1/2 ρv^3

From this equation we can see that the WPD relies only on the cube of the velocity of the wind and the density of that wind. It is important to remember that this indicates the amount of power per unit area available and indicates nothing about the actual power output of the wind turbines.