Bord Gáis Energy saw its adjusted operating profits rise by 74% in the first half of the year, as its parent company Centrica also reported a massive jump in earnings.
The Irish utility had an adjusted profit of £33m (€39.5m) in the first six months of 2022, compared to a profit of £19m (€22.7m) in the same period of last year.
Bord Gáis Energy's customer numbers rose slightly to 513,000.
However the firm said its improved performance was due to the return to service of the Whitegate power station in Co Cork at the end of last year, which allowed it to benefit more from rising energy prices.
Bord Gáis Energy has itself raised prices three times in the past year, with significant hikes made in August and October 2021 and again in April.
In its results, the company said the improved performance was "despite reduced retail margins in a challenging environment for energy supply."
Bord Gáis Energy's jump in profits came as its parent company Centrica announced group profits of £1.34 billion for the six month period - more than five times the amount it earned a year before.
That has allowed it to restore its dividend, with a plan to issue 1p per share to stake-holders.
"The past year has demonstrated the importance of well-funded, well-run energy companies," said Centrica CEO Chris O'Shea. "WE expect this to continue into the second half, underpinning continued investment in customer service and elsewhere in our portfolio.
"We are very aware of the difficult environment many customers are facing and we will continue supporting them."