Scottish and Southern Energy (SSE) is to break ranks with rival utilities by auctioning its power on the open market.
The move comes after Labour leader Ed Miliband pledged to break up the “rigged market” in energy which delivers massive profits to a few giant companies and swollen bills to consumers.
The big six companies sell most of the electricity they generate directly to consumers.
SSE plans to auction 100 per cent of its power on the UK’s day-ahead wholesale market by early next year, and will buy all the electricity its customers need from the same source.
It would remove one barrier to entry for new suppliers, which could drive down consumers’ bills due to greater competition.