Iberdrola SA (IBE.MC) Thursday said first-quarter power output rose 43% to 35,822 gigawatt-hours, boosted by last year's acquisition of U.K. utility Scottish Power and a rapid rise in coal-fired generation.
Iberdrola, Spain's largest power utility by market value, said coal-fired generation more than tripled in the period, and accounted for 11% of total output. Natural gas-fired generation - the main source of Iberdrola's power, representing 45% of total output - increased 80%.
Renewable-energy production, concentrated at the company's unit Iberdrola Renovables SA (IBR.MC), rose 80% and accounted for 14% of total output.
Most of the company's renewable output came from wind power. Iberdrola is the world's biggest wind power generator.
Nuclear power represented 19% of all company output, while hydropower accounted for just 6%, hurt by extremely low rainfall in Spain.
Iberdrola completed its GBP11.6 billion cash-and-shares takeover of Scottish Power in April.