'Big six' energy company SSE has increased prices for more than two million customers.
The price hike, effective from 11 July, will lead to standard dual fuel customers paying an average of 6.7 per cent more for their energy.
That means customers with typical dual fuel bills will pay £76 more per year.
SSE also said it was removing its £6 per fuel, per year, paperless billing discount from 11 July.
It blamed the price hike on increased wholesale prices and policy costs.
Chief commercial officer Stephen Forbes said: "We deeply regret having to raise prices and have worked hard to withstand the increasing costs that are largely outside our control by reducing our own internal costs.”
“Increasing energy prices is always a last resort. However, sustained increases in the cost of supplying energy, principally from higher wholesale energy prices and the cost of delivering government policy initiatives designed to modernise and decarbonise Britain’s energy system, must eventually be reflected in prices," he said.
Forbes also argued that low carbon policies such as the introduction of smart meters should be funded out of taxation rather than through energy bills.
"SSE Energy Services continues to believe that these policies should instead be funded more fairly through means-tested general taxation,” he said.
Read more: SSE-Npower merger to get more in-depth probe
The move by SSE means that all of the big six energy companies have announced price increases this year.
Earlier this month Npower increased its prices by 5.3 per cent.
Both British Gas and Scottish Power are set to boost bills by 5.5 per cent, affecting more than five million people, while EDF has a 2.7 per cent price increase coming into effect on 7 June for 1.2 million people.
SSE's adjusted pre-tax profits fell six per cent to £1.45bn in the year to the end of March.
Over the year, SSE lost 430,000 customers, with domestic energy accounts falling from 7.23 million to 6.8 million.
SSE is set to merge its UK gas and electricity business with Npower, which would transform the 'big six' into the 'big five' if it went ahead.
Earlier this month the Competition and Markets Authority confirmed it was launching a full investigation into the proposed deal after worries it could affect customers.