An argument commonly heard in the decision making process for the placement of wind turbines, is the alleged idea is that solar panels form a better alternative than wind turbines. The obvious advantages of solar panels (no moving parts, no wear and tear, no noise) are simply extended and are reasoned to apply also to the power production capacity. Therefore, it is interesting and entertaining to make a comparison based on energy yield only:

In the example below, we calculate how many solar panels are needed to approach the annual energy yield of a modern wind turbine. To calculate the yield we take an average annual wind speed of 7 [m/s], a value that is representative for most domestic areas of The Netherlands. For the solar panels the basis is an optimal orientation (0-5 ° SSW, 36 ° roof angle) and an average electrical efficiency of 15%.

Turbine yield: 1 x Siemens SWT-2.3-108 @ 7 [m/s] ≈ 8,5 [GWh/yr]

To match this yield, the following amount of PV panels is needed:

≈ 45.000 panels of 230 Wp

To install these solar panel a total surface is required of:

≈ 75.000 m2 ≈ 15 soccer fields (100m x 50m)

This is equivalent to about 3000 roof-tops when considering that the average roof area in the Netherlands measures 40 m² and that the average solar panel coverage on a typical roof is approximately 60%.