Energy aspects

In Switzerland, at an optimal tilt and orientation, solar irradiation varies from approximately 1000 to 1500 kWh/m2 per year. At the south of the Swiss Alps, the production of electricity corrisponds in average to approx. 140 kWh/m2 per year.

Surface [m2] Power installed [kWp] Annual energy production [kWh] Part of electrical needs [%]
6 (sc-Si)
7.5 (mc-Si)
1 1000 25
12 (sc-Si)
14 (mc-Si)
2 2000 50
18 (sc-Si)
21.5 (mc-Si)
3 3000 75
24 (sc-Si)
29 (mc-Si)
4 4000 100

*Assuming an average household consumption of about 4000kWh year.

This data has been calculated for crystalline modules (mono- and multicrystalline) in Switzerland.
For thin-film modules, the efficiency is lower but this is not so important if the available surface is large. In order to obtain the same installed power and annual energy production, the surface area values have to be doubled.