Hydropower plants along Slovenia’s main rivers generated 2,962.4 GWh of electricity in the first nine months of the year, a decline of more than 24 percent compared to the same period in 2024, when hydrological conditions were exceptionally favorable.
In September alone, hydropower output amounted to just over 301 GWh, around 26 percent less than in the same month last year. This continues the 2025 trend of lower generation compared to last year’s above-average results, which were driven by unusually high rainfall.
Despite the year-on-year decrease, actual production slightly exceeded long-term expectations. Hydropower plants on the Sava, Drava, and Soca rivers collectively surpassed their nine-month forecast by about 1.5 percent, even though overall generation remained below 2024 levels. The Drava basin recorded the steepest drop, with 1,740 GWh produced—about one-third less than a year earlier and roughly 5 percent below plan. In contrast, hydropower plants on the Soca river performed significantly better than expected, producing 30 percent more electricity than forecast, though still 3 percent lower than last year’s total.
According to the Environmental Agency, summer rainfall was highly uneven across Slovenia. The highest precipitation, exceeding 600 millimeters, was recorded in the Julian Alps, Trnovski gozd, and Javornik regions. About half of the country, particularly the southwest, received more than 300 millimeters of rain, while other regions saw between 140 and 300 millimeters. These differences in rainfall distribution were directly reflected in the varying hydropower production results across the country.
