The figure emerged as energy bosses were accused of abuse during a grilling in front of the Commons Energy and Climate Change Committee.
Directors of the Big Six faced questions from MPs over how they could justify rises of up to 10% this winter. But they hit back, insisting the increases were triggered by legitimate business costs.
And they banded together to attack green taxes on bills, which the Conservative s have already said they want to scrap.
Last night Labour leader Ed Miliband accused energy companies of offering only a list of excuses for their price rises.
During the hearing Labour MP Ian Lavery told energy bosses that the recently announced price rises, from four of the six firms, were an absolute outrage as he accused them of abuse.
Glasgow Labour MP John Robertson told Tony Cocker, chief executive officer at E.ON, that reassurances his company would operate a price freeze for as long as possible meant nothing without a specific time frame.
But the industry insisted that its costs, including on the transportation of energy, were going up and that they had to make a profit to stay in business.
William Morris, the managing director of SSE, also questioned whether green levies on energy were morally wrong.
That stance was backed by Mr Cocker, who described the environmental costs as a "stealth poll tax".
He called for them to be removed from customers' bills and included in general taxation instead, an idea has been floated by the Liberal Democrats.
He also revealed he had written to Prime Minister David Cameron calling for a Competition Commission probe into the industry.
Stephen Fitzpatrick, managing director of Ovo Energy, accused other energy companies of pushing environmental charges, along with higher bills, on to those customers they consider least likely to switch supplier.
He told MPs: "It looks to me like a lot of energy companies, a significant number of the Big Six, are charging the maximum price they feel they can get away with to the customers that they feel will not switch under any circumstances and then maintaining the illusion of competitive pricing with tariffs targeted towards a very small number of relatively well-engaged customers."
Earlier, Neil Clitheroe, from ScottishPower, told MPs any hike was an "extremely difficult" decision for energy companies to take.
He added 60,000 customers had called the energy giant over the last week "with worries about their bills".
An analysis by industry regulator Ofgem showed that, while the increases announced so far this autumn by some of the companies have averaged 9.1%, wholesale prices have risen by 1.7% - adding just £10 to the average household bill of £600.
l Last night Labour launched a new party political broadcast it said showed David Cameron's failure to act on energy bills was hurting families and businesses.
It featured people talking about the tough choices they face as winter nears, the party said.
Mr Miliband added: "The system is broken and we're going to fix it. The blame lies with government for not having had the strength to take this on.
"The real test of leadership is not whether you stand up to the weak, that's easy. The real test of leadership is whether you stand up to the strong. If we win that election in 2015, the next Labour government will freeze gas and electricity prices until the start of 2017."