Swiss hydro reserves have declined to their lowest level for this time of year since at least 1997, Federal Energy Office data showed Thursday.
Stocks were pegged at 11% Monday, or 970 GWh of a total capacity of 8.83 TWh for Swiss hydroelectric production.
Water reserves declined by 180 GWh in week 12, about twice as high a withdrawal as a week earlier.
At the same time last year levels were around 350 GWh higher after facing a series of 20-year lows.
Colder than usual temperatures at the end of winter led to low gas storage and price spikes in the power market, however with milder weather and the return of the 365 MW Beznau-1 nuclear plant near curve prices relaxed in recent weeks.
Front-month contracts in Germany and France however saw gains Thursday shortly before expiry with German April baseload adding 65 euro cent on the day to EUr35.25/MWh.
River levels on the Rhine on the border with Germany were sharply lower on the week at 70% of the long-term average, the data shows.
Alpine hydro levels usually build up from late spring; higher-than-normal snowfall so far this winter has also raised xpectations of higher inflows from the snow melt in the spring on reports of large snowpack at higher altitudes.
Hydro power accounts for roughly two-thirds of Swiss power generation, with nuclear accounting for most of the remainder.
