Scottish supplier SSE’s overall profits before tax rose 9.6% to £1,551.1 million last year.
The company put this down “mainly” to cash made back after investing in drilling for gas and major network upgrades.
Last winter it bumped up prices by 8.2%.
Sales from its wholesale gas business rose by 24.8%, the bulk of which came from an extra £90m profit after buying the Sean gas field.
However its retail supply business – including household sales – felt the nip of the mild winter, with profits down nearly a third (28.6%).
The firm said its profit margins for supply were 2.9% due to these milder temperatures and – an echo of rival Centrica’s comments earlier this month – a “very competitive” market.
At the end of March, SSE said it would freeze its standard household energy prices until at least January 2016.
Chief Executive Alistair Phillips-Davies claimed this would dent profits.
He said: “We introduced our price freeze right at the end of the last financial year and it has been hugely popular… [it] will mean we take a hit on retail profits over the next couple of years.”