The logo of Electricite de France SA (EDF) is pictured on the facade of a building in Paris, France, August 5, 2018. Picture taken August 5, 2018. REUTERS/Regis Duvignau

PARIS, France (Reuters) - French state-controlled utility EDF EDF.PA has been warned of a 24 hour strike at its power generation units in France from Jan. 21 at 2000 GMT, said electricity grid operator RTE on Sunday.

The power systems operator did not give reasons for the strike, nor whether it would impact electricity production.

The strike comes amid an expected rise in electricity consumption for heating due to a cold weather snap this week, according to forecasts.

France, unlike neighbor Germany, depends mostly on electricity for heating during prolonged cold spells. Power demand increases by around 2.5 gigawatts for every 1 degree drop in the average temperature below seasonal levels in France.

RTE’s forecast showed that the average temperature will remain around 4 degrees below the seasonal norm for most of the week, with the average daily peak consumption at over 85 gigawatts (GW), reaching about 90 GW on Thursday.