How do windmills make electricity?

1 Answer
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=(1/2)Arhov^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=(1/2)mv^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.