French-owned gas and electricity supplier EDF Energy has posted an 1.4% increase in UK annual earnings to £1.69billion, driven by the performance of its eight nuclear power stations including Sizewell B in Suffolk.

The company last year unveiled a deal to build a new nuclear plant at Hinkley Point C in Somerset and also has plans for a Sizewell C Plant.

EDF said it had invested £1.1bn on its existing nuclear and coal stations, its new nuclear project, new generation capacity, gas storage facilities and its customer supply business.

Underlying earnings rose 1.4% from £1.67bn in 2012 to £1.69bn in 2013 but, on a like-for-like basis and excluding the impact of accounting revaluations, earnings were up 4.1%.

The results did not reveal the scale of profits from EDF’s domestic supply business, which are expected to be published in June.

The division is expected to have remained loss-making in 2013, although it is likely to have narrowed the £92m shortfall reported the year before.

EDF, which serves around 3.9m households and is one of the so-called Big Six UK energy suppliers, raised its domestic tariffs by 3.9% from January, a lower increase than many of its rivals.

Its total number of gas and electricity accounts is 5.7 million, a net increase of 250,000 in 2013 and 600,000 over the last three years.

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.”

EDF’s group-wide profits of 16.8bn euros (£13.8bn) represented a 5.5% increase on 2012 on a like-for-like basis.