A reader asks: How many windmills would we need per person to replace fossil fuels? How much room would this take up?
In the United States, we consume 5.4 terawatts (5.4 * 1012 Watts). The average wind turbine is a couple of megawatts, for convenience, let’s say 2.7 megawatts (2.7 * 106 Watts).
(5.4 * 1012 Watts) / (2.7 * 106 Watts) = (2 * 106 ) = 2 million turbines.
If 2 * 106 turbines would serve 3.3 * 108 people, each turbine would supply 3.3 * 108 / 2 * 106 , or 165 people.
For the area of land required, there are 3.5 * 106 square miles in the continental U.S., and 6.4 * 102 acres in a square mile, meaning that there are 2.3 * 109 acres. There are 1.5 acres required per turbine, so we have room for about 1.6 * 109 turbines.
Thus, converting the entirety of Americans’ energy use to wind would require about 0.1% of the total land mass.
We also need to keep in mind that this land can serve other purposes simultaneously, e.g., grow crops, and raising animals.