Swiss nuclear power plants are currently still a pillar of the Swiss electricity supply system and account for around 30% of annual electricity production. There are 5 nuclear power plants in Switzerland. These are Beznau 1 and Beznau 2, Gösgen, Leibstadt and Mühleberg. The latter is now out of operation. Together, the power plants still in operation contribute just under 3000 MW of electrical output to Switzerland's production fleet.

The nuclear power plants require regular maintenance. Accordingly, shutdowns are planned time and again, which reduce the available output of the plants in the production fleet. Particularly high temperatures and drought can also have an impact on production, as cooling bottlenecks can occur. For example, rivers may not carry enough cool water. In addition, unplanned outages occur time and again despite careful maintenance. The tooltip displays the number of planned and unplanned outages.