With a share of over two thirds, non-renewable sources of energy dominate Switzerland's energy consumption. This makes the country dependent on imports. Petroleum, followed by nuclear energy, dominates the fossil energy mix. In order to achieve its climate targets by 2050, Switzerland is striving to significantly reduce the share of fossil fuels.

Non-renewable energies account for around 70% of total consumption in Switzerland. Petroleum dominates the energy mix with a share of more than one third of total consumption, followed by nuclear energy with about one fifth and natural gas with one tenth. These energies are almost exclusively imported, making Switzerland dependent on other countries for its energy supply. The Energy Strategy 2050 foresees the progressive reduction of the share of non-renewables and the phasing out of nuclear power.

The consumption of energy (electricity, petrol, heating oil, district heating) generated using fossil fuels stood at 84% in 1990. In 2021, this figure was 59%. Petroleum-based energy is the most prominent type of non-renewable energy in this context: while it accounted for 24% of total consumption in 1950, it reached a hefty 80% at its peak in the early 1970s. In 2021, this figure stood at 43%, with heating oil consumption falling and fuel consumption rising at the same time. Switzerland imports most of the petroleum it uses from other European countries in the form of finished products. Only one fourth of the petroleum used in Switzerland is refined domestically; there is only one Swiss refinery.

Nuclear energy came to Switzerland in 1969 with the commissioning of the Beznau I nuclear power plant in the canton of Aargau. Beznau II, Mühleberg (canton of Bern), Gösgen (canton of Solothurn) and Leibstadt (canton of Aargau) followed. In 2011 the Federal Council decided that nuclear energy would be phased out, with no new nuclear power plants to be built and the five existing ones to be decommissioned when their operating licences expire. The Mühleberg plant was the first to be decommissioned, in 2019, with the next shutdown – that of Beznau I – expected in 2029.

Natural gas has been used in Switzerland since the beginning of the 1970s and must be imported in its entirety. While its main use is to heat private households, one third goes to industrial production. Long-term contracts ensure the supply of gas (with Norway, formerly with Russia, and with some EU member states and other countries) and its storage (in Austria, France, Germany, Italy and elsewhere). Switzerland is connected with the international natural gas transport network at twelve entry points and is also an important transit corridor for Northern Europe's gas connection with Italy.