Spain set to rule on Endesa appeals on Nov 10

The 19 conditions, imposed by Spain's energy market regulator CNE, have been declared illegal by the European Commission, which has given Spain until Thursday to respond to its ruling.

"Even though the response time over the conditions runs out on Thursday, we are keeping to the date of Nov. 10 which is when we have to respond to E.ON's appeal against the CNE," the ministry source said.

"Even though they are two different processes, we are treating them in parallel."

The source said the ministry was continuing to negotiate with the European Commission after it opened an infringement procedure -- a step towards court action -- against Spain last week.

Industry Minister Joan Clos said he was surprised by the EU action as Spain had been negotiating with the Commission at the time.

"It's a controversy that we continue to study and the government's response will be known in the coming days," Clos told reporters on Tuesday.