But those profits are coming under intense scrutiny from lawmakers, and harsh criticism from consumers.
The average energy bill is expected to rise 83% from its current level to top £3,600 ($4,397) a year beginning January for millions of UK households, according to estimates from research firm Cornwall Insight published Tuesday.
That’s up 7% from its previous estimate made in early July.
As a result, the firm expects the average household will spend more than £300 a month ($366) to power their homes. And the pain will continue well into next year and beyond.
“It is not only the level — but the duration — of the rises that makes these new forecasts so devastating,” Craig Lowrey, a principal consultant at Cornwall Insight, said in a press release.
“This level of household energy bills currently shows little sign of abating into 2024,” he added.
Activists have been sounding the alarm for months. By January, more than half of UK households — about 15 million — are predicted to fall into “fuel poverty,” spending more than 10% of their overall income on energy, according to estimates by the Child Poverty Action Group.
Earlier this year, the UK government said it would introduce a 25% tax on the profits of energy producers, which is expected to collect around £5 billion ($6 billion). The tax will help pay for a package of support worth around £15 billion ($18 billion), including a £400 ($488) grant to 29 million households from October.
But the grant will only “scratch the surface of [the] problem,” according to Lowrey.
“Our new figures show that even increasing support for October will not make much of a dent in what is likely to be a sustained period of high energy bills,” he said.
— CNN Business’ Julia Horowitz contributed reporting.