Seeking to enhance energy independence, the federal law passed in autumn 2023 comprises measures to boost the transport, storage and production of electricity, including facilitating the installation of solar panels on buildings.
It also includes provisions to fund these measures.
The energy law, which was put to a referendum by opponents who argued it would be too costly and was not fit for purpose, was backed by more than two-thirds of voters, preliminary results and projections published by public broadcaster SRF showed.
It is now expected to take effect next year.
Switzerland has been at loggerheads over climate change with a top European court, which in April ruled it was not doing enough to combat global warming.
Two separate initiatives were defeated that either sought to tie health insurance contributions to income levels or put curbs on increases in the levy, the results showed.
Critics of the health plans had argued they risked sparking higher taxes, just as the government grapples with how to fund additional pension payments that are due to come into effect in 2026 and were backed by Swiss voters in March.
The proposals to contain health insurance costs had enjoyed majority support earlier in the campaign, polls showed.
