(Montel) French weather service Meteo France issued a 40C heatwave warning on Monday for 21 regions across France, while utility EDF will shut down nearly 3 GW of nuclear capacity this week amid cooling water issues.
Low river flows and high water temperatures can force operators to cut output if it breaches environmental limits.
Flows on key French rivers had “significantly” weakened over the last two weeks amid persistent hot and dry weather, the ministry of energy told Montel recently.
The St Alban 1 and 2 (2.6 GW) reactors, meanwhile, saw their output cut over the weekend, and though both reactors are now back online, EDF warned last week it could curb output at its nuclear plants located along the river Rhone – which also included Bugey (3.7 GW) – due to declining flows amid the hot weather.
The temperature of the Rhone around St Alban and Tricastin was currently 26C, while it was 23.4C at Bugey, estimates from Montel’s Energy Quantified showed, with 28C deemed unsafe.
French TSO RTE expected power demand to peak at 59.4 GW on Thursday and 58.6 GW on Friday, with a surge expected due to an increase in need for cooling.
Today, demand should reach a peak at 57 GW at noon, according to the TSO.
The previous consumption peak this summer occurred on 27 June (59.46 GW), close to the record high 59.6 GW set on 22 June 2017
Day-ahead baseload power was last seen down EUR 0.59 at EUR 41.80/MWh on the Epex Spot exchange, while peakload was up EUR 0.53 at EUR 45.39/MWh.
Temperatures in the south of the country were set to climb to 39C this afternoon, with the heat spreading throughout France on Wednesday and Thursday – the hottest days of the week – with it reaching 40C or higher, said Meteo France.
This new heatwave would be shorter than the one that occurred at the end of June – which saw record high temperatures – with cooler air expected from Friday, added the forecaster.
Forty of EDF’s 58 nuclear reactors are located near watercourses.