According to Karrer, the Swiss energy supply situation could become acute after 2020, if the country’s two oldest nuclear plants close down and supply contracts with French nuclear plants are not renewed.
He estimated that, if no action was taken to replace existing capacity and import contracts, the supply gap could reach between 10 and 30 terawatt-hours (TWh) by 2030 – between 15 and 33 per cent of total anticipated annual demand.
This situation – which mirrored a similar looming crisis at Europe-wide level – could be particularly serious during winter months, when a supply gap could begin arising as early as 2012.
And Karrer added that options were limited – energy efficiency and conservation measures were not even capable of keeping pace with annual demand growth, new renewable energy sources were "nowhere near" being able to meet the gap, and the potential to expand Swiss hydro-power capacity was "very limited".
Switzerland currently produces some 40 per cent of its electricity from five nuclear power plants and the vast majority of the rest from hydropower.
The issue is also complicated by the fact that the other main existing option – gas or coal-fired plants – produce significant quantities of carbon dioxide.