SSE Renewables output in the first quarter of the financial year was 15% lower than planned, mainly due to the impact of the weather.
Total clean power generation from 1 April to 30 June was 1988 gigawatt-hours (GWh), below the 2352GWh planned for the period.
However, output in the quarter was up on last year’s 1879GWh, as a result of increased hydro generation, the company said.
Onshore wind generation in the UK and Ireland was 878GWh, below the 1036GWh planned and also lower than the 941GWh produced in the same quarter of 2019.
Offshore wind output was 410GWh in the latest period, up on the 407GWh generated last year, but below the 467GWh planned for the three months.
Conventional hydro output was 674GWh, up from 482GWh last year, but lower than the 774GWh projected for the period.
SSE reiterated that the impact of coronavirus on the wider economy will have adverse, albeit temporary, effects on several of its businesses during the 2020/21 FY.
The greater impacts are likely to be experienced in the first six months of the year, it said.
Coronavirus impacts on operating profit for the first three months of trading are in line with expectations, with the total for 2020/21 anticipated to be in the range of £150m to £250m before mitigation.
SSE said it continues to keep this assessment under review and will provide guidance on adjusted earnings per share later in the financial year.