Italy's photovoltaic plants generated 5.32 TWh of electricity in September 2026, up 1.14 TWh or 27.1% on September 2025, according to monthly data published on 21 October by transmission system operator Terna and analysed by pv magazine Italia. About 731 GWh of the increase came from newly installed capacity and about 404 GWh from higher yields.
Demand at a 12-year high
National electricity demand reached 27.8 TWh, 6.5% more than a year earlier and the highest September level since 2014. September was about 2°C warmer than a year earlier; adjusted for temperature, demand still rose 4.6%. Terna says demand has grown every month since September 2025, and peak load reached 56.1 GW. Growth was strongest in the south and islands, at 8.3%, followed by the centre at 7.7% and the north at 5.3%.
Solar up, hydro down
Despite the solar surge, total renewable generation rose only 0.6% to 10.94 TWh, because hydroelectric output fell 29.2%. Wind added 0.8% and bioenergy 3.5%, while thermal generation rose 14.7%. Renewables covered 39.4% of demand, and solar supplied almost half of all renewable electricity in the month. Domestic production met 85.2% of demand, with net imports, up 7.7%, covering the rest.
Nine months of growth
From January to September, solar output was 20.5% higher than in the same period of 2025, and renewables covered 42.1% of demand, which itself rose 5.2%. Italy added 4,834 MW of solar capacity in the first nine months, 18.6% more than the 4,078 MW added a year earlier. According to Terna figures reported by Teleborsa, installed solar capacity reached 48.3 GW at the end of September.
Storage additions slow
The picture for batteries is different. Standalone storage added 911 MW of power in the nine months, 38.6% less than the 1,482 MW added a year earlier, while new usable storage capacity fell 55.2% to 1,962 MWh from 4,376 MWh. Terna counted 984,831 storage systems in operation at the end of September, and Teleborsa puts Italy's electrochemical storage fleet at 20 GWh and 8.3 GW.
What it means for European developers
Italy's data show solar growth keeping pace with rising demand, but also the gap that opens alongside it. When hydro is weak, gas still fills the evening, as the 14.7% rise in thermal generation shows. A sharp slowdown in new storage means more solar output is concentrated in the same sunny hours, which raises the risk of falling midday prices and curtailment. With solar additions running ahead of last year, that pressure will only grow without more batteries. For developers and EPCs, projects that pair PV with storage, or that are sited in the centre and south where demand is growing fastest, look best placed for the next phase of Italian solar.
Sources: Terna data via pv magazine Italia and Teleborsa.
