The group reported a 6 per cent fall in adjusted pre-tax profit to £1.45 billion in the year to 31 March, while bottom-line profits tumbled 39 per cent to £1.09bn. Revenue rose 8 per cent to £31.23bn.
SSE pointed to competitive pressures as it saw the number of domestic energy accounts fall from 7.23 million to 6.8 million.
Operating profit at its household supply business was flat at £260.4 million, despite higher energy consumption in the final quarter as customers turned up the heat to combat the Beast from the East.
SSE also recognised £213.3m worth of exceptional charges, including more than £60m in IT costs related to its deal with Npower.
Chairman Richard Gillingwater said: “As expected, 2017/18 presented a number of complex challenges to manage, but SSE’s operational performance was generally very robust.
“The challenges will continue in 2018/19, which is also expected to be a year of major transition for SSE.
“For investors, by giving clarity on the dividend for the five years to March 2023, SSE is demonstrating that remunerating them for their investment is and will remain its first financial objective.”
The deal to merge Npower and SSE’s retail operations is undergoing a competition investigation after the two energy giants failed to address concerns.
Under the proposed deal, the new company will be listed on the London Stock Exchange, with SSE shareholders holding 65.6 per cent and Npower owner Innogy holding 34.4 per cent.
SSE said the deal remains on track for completion in the last quarter of 2018 or the first quarter of 2019.