This month's final electricity bills for people on variable tariffs will be the highest for a few years, according to estimates.
After three weeks of increases in the price of power, energy companies' customers who don't have fixed-price rates will need to pay 20 per cent more in January than a year ago.
The rise comes after the electricity bought on the daily open market by power companies has got more expensive, with cold temperatures pushing up demand and fewer storms reducing the amount of cheaper wind and hydroelectric energy being generated. Also, storms in France have reduced the output of nuclear energy.
The average household bill will be 63 euros in January, of which 29 euros is made up of the power cost itself.
Forecast rain is expected to decrease costs slightly as more hydroelectric power will be generated.