The price of cheap energy is set in such a way that energy suppliers cannot always pass savings onto their customers, research has shown.
Consumer Focus reveals that even in times where wholesale gas prices fall, gas and electricity costs remain the same for domestic users.
This is because energy providers buy energy in bulk in advance on an estimated price set by the oil companies.
Industry watchdog Ofgem has launched an investigation into why energy suppliers cannot pass on any savings they make on wholesale prices, ThisisMoney reports.
Meanwhile, Ofgem is also looking into ways of simplifying energy bills and making cheap electricity tariffs easier to understand.
Last month it launched an investigation into the reasons why the Big Six were quick to raise prices for customers when wholesale costs increase but slower to bring them down afterwards.
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