The UK's energy price guarantee is expected to save a typical energy bill payer around £630 in the first quarter of next year.
It means the state is facing an estimated bill of £16billion to subsidise household energy bills from January to March.
The Resolution Foundation think tank, which calculated the cost, said the figure was eye-watering, but a "price worth paying" to avoid worsening the cost-of-living crisis.
Exact amounts will depend on each family's energy usage.
The Telegraph says shortages of gas due to Russia's war on Ukraine have triggered soaring wholesale energy prices which are feeding through into bills.
Ofgem, the energy regulator, on Thursday set the energy price cap for the period from January to the end March at £4,279 per year - a sharp rise to reflect higher wholesale costs.
Subsidised bills
The price cap would normally determine what households pay. However, the Government has decided to subsidise bills so that typical households are paying no more than £2,500.
The state is paying suppliers the difference between the price cap rate and the subsidised rate.
The Resolution Foundation said: "The energy price guarantee is set to save a typical energy bill payer around £630 between January and March next year.
"High energy use during the winter months - 45% of annual household gas use takes place in the first quarter of the year - means that it is this period when the benefits (and costs) of the energy price guarantee are highest."
Support for energy bills will be scaled back next year, Chancellor Jeremy Hunt has announced, with the level of the energy price guarantee rising from £2,500 to £3,000.
However, analysts at Cornwall Insight believe the measure will cost £42billion over its 18 months - up from a previous estimate of £38billion.
Support is essential
Craig Lowrey, principal consultant at Cornwall Insight, said: "With so many households struggling to pay their bills, it is essential that support is made available, however it is clear that the energy price guarantee is not a desirable long-term solution."
The National Grid and some energy firm are paying customers to turn off their gas and electricity at peak times of the day to save supplies.