SSE has unveiled plans to auction its entire power output in the day-ahead market.
The move comes after the UK Government sought more competition in the energy sector, which will provide better price transparency for consumers.
Currently, SSE, Centrica and four other generators supply 99% of the nation's power and gas requirements.
The company expects to be trading 25% of its supply and demand by November and aims to sell all its power by the end of 2011.
In June, the UK regulator Ofgem proposed that all utilities must auction 20% of electricity from next year, reports Bloomberg.
Final measures are expected to be announced by the end of the year.