Underlying profitability was down 12.9 per cent on 2012, with adjustments to the value of gas generation assets outweighing an increase in nuclear output.
However, earnings before interest, tax, depreciation and amortisation (Ebitda) rose 1.4 per cent to £1,689 million.
The company’s eight nuclear power stations generated 60.5TWh of electricity, the highest output in eight years.
Dungeness B is set to be kept open until 2028, with a 10-year life extension likely to be announced in 2014. That means seven stations will still be running in 2023, when new plant Hinkley Point C is due to come online.
On the supply side, EDF Energy made a net gain of quarter of a million household customers. It boasted the cheapest standard variable tariff of the major suppliers for 95 weeks out of 104 in 2012 and 2013.
EDF Energy chief executive Vincent de Rivaz said: “Our financial performance means we can make the big investments the country needs to give it the reliable low carbon energy it needs now and in the future. It also means we can invest in jobs and skills for the long term.
“The investment we are making in our existing nuclear power stations has resulted in their best performance for eight years. We believe that their operating lives can be safely extended and we expect to be able to announce a 10 year life extension for Dungeness B before the end of 2014. This means existing nuclear can hand over directly to the next generation of nuclear power stations without the need for more fossil fuel generation.
“Our customer numbers also continue to grow. We took early action to limit price rises and will continue to work closely with policy-makers to bear down on rising costs for consumers. We will listen to our customers and their concerns and take action on their behalf wherever we can.”