Regulator Ofgem has proposed a price cap on default dual fuel energy bills of £1,136 a year. The cap would be in place by the end of the year, it added.
Ofgem said it would review the price caps twice a year until 2023, by which time it aims to have introduced measures that would increase competition in the UK electricity and gas markets.
The price cap applies to the so-called standard variable tariff (SVT), the most popular type of rate offered by the big six energy suppliers, as well as other default deals. Customers on SVT pay on average £1,185 a year.