Around 40 people in France, mostly elderly, have died in a heatwave over the past week and Czech energy grid operator CEPS announced a state of emergency today after its power network was overloaded.
Blackouts forced some Czech firms to trim operations and conserve power and CEZ, Europe's second largest electricity exporter, said it had stopped exports for two days to boost local supplies after several generators failed.
The heatwave has boosted power demand across Europe as consumers turn up their air conditioners.
Meteo France, the national weather agency, has put its heatwave alert at orange, the second highest level, in 53 of the 96 metropolitan departments, or administrative districts.
A top French health advisory body (INVS) said it would publish on Thursday a detailed toll from the heatwave which has so far proved less deadly than the 2003 hot spell which killed some 15,000 people.
Labour Minister Gerard Larcher met construction industry representatives on Tuesday to discuss safety issues linked to the prolonged spell of high temperatures, notably adapting working hours to avoid the worst heat of the day.
Further north, the Dutch meteorological institute KNMI said July was on track to be the hottest month in the Netherlands since temperatures were first measured in 1706.
Average daily temperatures in the first 24 days of the month were 22.3 degrees Celsius (72.1 Fahrenheit) compared with the previous record of 21.4 degrees in July 1994 and normal average temperatures of 17.4, the KNMI said.
Dutch temperature records, launched at the beginning of the 18th century, are among the oldest in the world. Methodical thermometer-based records began on a more global basis around 1850.