ScottishPower, owned by Spanish utility group Iberdrola, saw lower earnings in the first quarter of this year, impacted by network investments and mild weather.
The Glasgow-based firm, which earlier this week agreed to pay an £18 million penalty for poor customer service, posted combined earnings of £482.6m.
The UK networks business’s earnings declined 6.8 per cent as ScottishPower pushed ahead with the multi-billion upgrade of its distribution and transmission equipment, while the generation and supply business was down by 3 per cent on the previous year amid lower demand for heating.
Weather conditions also hit the renewables business, with earnings 27 per cent lower than in the first quarter of 2015.
Despite that setback, the company has been awarded a five-year contract to build 102 turbines for its East Anglia ONE project off the eastern coast of England.
The agreement, worth up to £833m over five years, is Europe’s largest single contract for the supply of offshore wind turbines.