The Department of Energy and Climate Change said it is up to the energy companies to justify their profits.
A departmental spokesman said: "Profits are a matter for energy companies to justify to their customers and shareholders, but profits are needed if they are to continue to invest in Britain's energy security and infrastructure".
More top news
Sadly, these high-school students have already received the most abrupt and cynical lesson of their lives.
A top temperature of 9 or 10 Celsius (48-50 F).
The poll comes ahead of a debate in the House of Commons on Friday on a new Bill which would introduce such a system in England.