Forecasts for tight thermal capacity and rising demand next week boosted European spot power prices on Friday for Monday, the coming week and next month.
German and Austrian power plant capacity is likely to fall by 0.8 percent by May 16, data on the European Energy Exchange's (EEX) website showed.
German nuclear supply remains reduced at 8.8 gigawatts (GW) with the Grohnde and Gundremmingen B reactors offline for maintenance, and output also reduced at the Isar 2 reactor.
The German baseload power contract for Monday delivery rose 75 cents over Friday to 29.35 euros ($40.7) a megawatt hour.
The contract for weekly baseload delivery in Germany was at 31.75 euros and that for June at 29.50 euros.
French baseload power for Monday gained 4.75 euros from the Friday level to 28.75 euros/MWh.
German consumption on Monday will likely be stable at 61 GW and consumption in France is due to rise by 5 GW to 49 GW on Monday, Thomson Reuters Point Carbon data showed.
This reflected the return of French industry after a holiday on Thursday and greater exposure to cooler weather in the region.
Daytime temperatures in Germany will fall to between 12 and 17 degrees Celsius by Monday from 13 to 20 degrees on Friday, met office DWD predicted.
Wind power output in Germany on Monday will be high at 10 GW but still down 2 GW from Friday and compared with 16 GW on Sunday.
Forward power prices trended firmer, reflecting higher gas, carbon and oil, and stable coal prices.
The German Cal '15 baseload power contract for annual delivery in 2015 was 10 cents up at 34.50 euros. The equivalent French Cal' 15 contract was indicated unchanged at 41.90 euros.
Germany's output of renewable power in the first quarter of 2014 rose by 12.6 percent from a year earlier and the share of renewables in overall national consumption rose by 4 percentage points to 27 percent, industry group BDEW said.
In company news, EnBW, the third-biggest utility, posted a 15 percent lower core profit in the first quarter, weighed down by the mild winter, low wholesale prices and the rise in renewable capacity that has hit its thermal power plants.
($1 = 0.7214 Euros)
(Reporting by Vera Eckert; Editing by Susan Thomas)