How do windmills make electricity?

Apr 7, 2018

The kinetic energy of the air molecules hitting the fan blades are turned into electrical energy.

Explanation:

According to this booklet in table 8.1 the power output of a wind turbine is given by:

$P = \left(\frac{1}{2}\right) A \rho {v}^{3}$

$A$= Area created by the turbine blades (using the blade length as the radius)
$\rho$= the air density (in kg)
$v$= the speed of the wind

This looks very similar to something else...

${E}_{k} = \left(\frac{1}{2}\right) m {v}^{2}$

The formula for kinetic energy.

This is because the wind turbine is based on using kinetic energy. A wind turbine's energy output is determined by how many air molecules are hitting it at a given instance and with what speed- their kinetic energy. The kinetic energy of the air molecules is transferred to the turbine blades, which gives the blades kinetic energy. In turn, they transfer their kinetic energy to a generator or alike, which can produce electrical energy.