Britons have been warned that the price cap is set to reach £3,300 this winter, meaning average household energy bills will have tripled since last summer.
Analysis by the Energy and Climate Intelligence Unit (ECIU) estimates that soaring gas prices alone could add £2,000 to the average bill.
That would be more than 90% of the expected increase in the energy bills, according to the report.
The ECIU notes that wholesale gas costs are set to have added around £1,200 to gas bills, an increase of nearly 500% from before the crisis.
Analysts suggest the knock-on effect on the power market means that gas will have pushed up electricity wholesale costs on bills by more than £700 a year, an almost 400% increase.
Dr Simon Cran-McGreehin, Head of Analysis at ECIU, said: “With the gas price so high and volatile, and set to remain so, the question is: where’s the plan? As the Institute for Fiscal Studies has already pointed out, a £17 billion winter bailout for bills isn’t sustainable for years to come.
“The very obvious answer is to help people to use less gas, but the government has had itself in a muddle over energy efficiency.
“The ECO insulation scheme has worked well and is knocking £600 off the bills of fuel-poor households, but the government is non-committal on doing more.
“We have to consider the security of supply too, but more UK gas won’t come online anytime soon, won’t bring down bills and for many will have the whiff of ‘let them eat cake’ about it.”