RWE, the parent company of npower, has released its financial results for 2011, which have revealed its UK operations saw a significant rise in profits.
It reported returns of £313 million for npower, up from £232 million the previous year - a rise of 34 per cent.
The firm said the rise was down to higher income from its power generating operation and greater cost savings.
Last October, it hiked prices for gas by 15.7 per cent and electricity by 7.2 per cent - though it confirmed a drop of five per cent in gas tariffs in January.
Chief executive of npower Volker Beckers said the firm recognised consumer concerns about high energy prices, which is why it will be investing in new infrastructure to reduce the UK's exposure to volatile energy markets.
Commenting on the results, director of policy and external affairs at Consumer Focus Adam Scorer said: "A rise of a third in profits will clearly leave consumers questioning whether further savings could have been passed on to customers."
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