Earlier this week, E.ON said it did not expect to have to raise prices in the next 18 months "as a result of social or environment obligations".
But E.ON also warned, "There remains a risk, however, that increases in network charges or wholesale energy costs for example could force a price increase".
The announcement followed the Government's shake-up of green levies on Monday.
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The report also said that many graduates do not even see a 'earnings premium' from their years at university.
The country's counter-terrorism forces have regained control of the facility.
The commissioner of the Metropolitan Police has said he cannot promise the public an attack will not take place.