More than half of British households are set to see an increase in the cost of energy in April after the regulator, Ofgem, raised price caps.
Ofgem sets maximum prices that can be charged for gas and electricity to those who have not switched suppliers and are on default tariffs.
The new cap could see these households typically pay an extra £117 a year.
The regulator is allowing suppliers to cover the higher costs they face on the wholesale market.
“We can assure these customers that they remain protected from being overcharged for their energy and that these increases are only due to actual rises in energy costs, rather than excess charges from supplier profiteering,” said Dermot Nolan, chief executive of Ofgem.
About 11 million households are on default, or standard variable tariffs, and are set to be affected. Such a household, which uses a typical amount of energy and pays the bill by direct debit, should now expect to pay £1,254 a year.
Consumer groups say they can shop around for a better deal.
Another four million people are on prepayment meters, so pay for their energy in advance. The price cap will rise on their tariffs too, with the typical customer paying £1,242 per year, up by £106 from the previous cap level.
How do these caps work?
Energy price capping is a flagship government policy designed to protect the vulnerable and those who have stayed loyal to their energy supplier.
Ofgem sets the cap for households in England, Wales and Scotland. Northern Ireland has a separate energy regulator and its own price cap.
Ofgem sets a cap on the unit price of energy for electricity and gas, and a maximum standing charge.
Energy companies are not allowed to charge default tariffs that are higher than these thresholds.
The first cap came into force at the start of January. Ofgem said this price limit meant households typically saved £76 a year on what they would have been charged without the cap.
Ofgem has now reviewed the cap and will allow suppliers to charge more from April.
The cap for those on prepayment meters came into force earlier but has also been reviewed and revised up.