Scottish and Southern is latest to raise energy prices

Key Points

• Gas up 18%

• Electricity up 11%

• Rises take effect on 14 September

It will hike electricity rates by an average 11% and gas by 18% on 14 September in a move that hits 5.2 million electricity and 3.6 million gas customers.

The rises affect all SSE tariffs other than those on a fixed rate. It means the typical annual dual fuel bill (where both gas and electricity is supplied) will jump from £1,094 to £1,265.

After that, SSE has made a commitment not to implement another household increase before August 2012.

British Gas and Scottish Power have also announced rises of up to 19%, to take effect on 18 August and 1 August, respectively.

Like its rivals, SSE blames a jump in costs for the rises. It says wholesale prices (the price it pays for energy), distribution rates and environmental costs have all increased over recent months.

Escape lock-ins

SSE customers can escape from variable tariffs that appear to lock them in, if they'd benefit from switching.

Many gas and electricity deals come with an exit fee of up to £100 (though typically around £60) for those who leave before the term of the deal ends.

But where a supplier puts prices up, because that results in a contract change that's detrimental, rules from regulator Ofgem mean many consumers don't need to pay that penalty as long as they inform their power firm they wish to switch before the increase.

SSE confirms you must contact it before the price hike on 14 September if you wish to leave and escape a penalty.

The amnesty does not apply to those on a fixed rate deal because the price of their tariff will not rise, due to the nature of the product.

The same principle applies to British Gas and Scottish Power customers, who must inform their provider by 18 August and 1 August, respectively.