* One third of EDF's nuclear power fleet still offline
* Europe faces more fragile supply context this year
* RTE could be forced to clip some demand during peak use
By Marion Douet
MONTESQUIEU-DES-ALBERES, France, Oct 17 (Reuters) - French state-owned utility only has six weeks left to ensure its troubled fleet of nuclear power reactors is capable of producing enough electricity to cope with winter demand, the French power grid's head said on Wednesday.
Around a third of EDF's 58 nuclear reactors -- which are on average 26 years old -- have been offline since April due to a maintenance, problems restarting some of the ageing reactors and unexpected outages.
This has led to questions over the energy company's ability to adequately supply its customers in time this winter with supply already been hit by hitches at French and Belgium reactors.
Dominique Maillard, the head of RTE, the transport arm of the utility, told Reuters EDF would need to be ready by December or even mid-November.
"But I prefer to have a poor availability rate now than in December," said Maillard. EDF carries out most of its maintenance during the spring and autumn to ensure they are available during summer and winter peak demand.
"In certain cases we could be forced to clip some demand during peak demand, which does not mean plunging France in the dark but cut supplies for some clients for a short period," Maillard added.
"What worries us is that the conditions are not as favorable as they were last year."
EDF consistently fails to meet its forecast availability targets published on RTE's website. For a link please click: link.reuters.com/jym43t (Additional reporting and writing by Muriel Boselli; Editing by Mike Nesbit)