It does not, but they are storing the energy for winter. Solar produces a lot more energy in summer, which is especially true in Switzerland or Europe in general.
The difference depends on your latitude. On the equator the seasons won't make a difference, above the arctic circle you'll get diddly-squat from your panels in the winter during the endless night. Switzerland is at 47 degrees, not quite arctic circle but far enough north to see a huge difference.