Environmental measures are adding about £60 to the average household energy bill this year, the market watchdog said yesterday, as EDF Energy became the second leading supplier to raise prices.

Ofgem, which regulates gas and electricity markets, said the combined effect of the European Union's emissions trading scheme, the renewables obligation (RO) for subsidising green electricity such as wind power, and the new carbon emissions reduction target (CERT), the energy efficiency programme that comes into effect in April, would add about 6 per cent to the average bill.