LONDON, March 6 (Reuters) - The British energy regulator said on Tuesday it is committed to implementing a cap on prices for millions of households by the end of this year, providing parliament passes the necessary legislation before a summer recess.
* The regulator, Ofgem, will be given new powers to set and implement price limits by legislation introduced last week and expected to pass in time for the cap to be in place by winter.
* Ofgem said it aimed to cap prices for 12 million households, which it says are paying as much as 300 pounds ($415) more than those on the cheapest tariffs. It already reduces the bills of 5 million households using pre-existing powers.
* "Ofgem has today committed to put the cap in place by the end of the year, provided that legislation is passed as expected before parliament rises for the summer recess," it said.
* It sent a letter on Tuesday to energy providers and other stakeholders setting out how it will create and implement caps, including a series of consultations between now and August. https://www.ofgem.gov.uk/system/files/docs/2018/03/update_on_our_plans_for_retail_energy_price_caps.pdf
* Price caps are then to be set in the autumn and implemented by the end of 2018.
* Six companies supply 78-79 percent of energy to domestic customers in Britain - Centrica (Frankfurt: A0DK6K - news) 's British Gas, SSE (Amsterdam: UW8.AS - news) , E.ON, EDF Energy, Innogy's Npower and Iberdrola (Amsterdam: ID6.AS - news) 's Scottish Power.
* Home power bills have doubled in Britain over the past decade to an average of about 1,150 pounds ($1,500) a year.($1 = 0.7222 pounds) (Reporting by Sabina Zawadzki; Editing by Dale Hudson)