Energy giant Npower announced a drop in profits on the first half of 2014 by 38%.
From January to June last year profits dropped from £176 million to £109 million this year, according to the first half figures.
They lost 62,000 domestic customers, with the total at just over 5.37 million.
Its electricity generating arm also suffered: RWE Generation UK posted a £74m loss from its UK power station fleet, compared to a loss of £21 million in the first six months of last year.
It put this down mainly to the “continued problems with the economics of gas-fired power plant” as well as having to close older coal and oil-fired power stations at Didcot, Tilbury and Fawley in 2013.
Paul Massara, CEO RWE npower claimed the results show the difference between “energy company myth and reality”.
He said: “In the first half of the year, npower has made a profit of £109 million, or just £14 per customer account, yet has delivered tens of thousands of energy efficiency improvements in houses across Britain through the Government’s ECO strategy; RWE Generation has today reported a loss of £74m in Britain, yet RWE has invested more than £300m in this country so far in 2014, creating growth in renewable energy supported by an efficient and flexible conventional power station fleet.”