Solar time and energy: how much is convenient

On the night between Saturday 24 and Sunday 25 October 2026, the clocks will go back one hour. The transition to solar time marks the definitive entry into the winter months: we will have more light in the morning, but the days will drastically shorten in the afternoon, forcing us to turn on the lights in our homes and businesses earlier.

This seasonal event arrives at a time when the topic of energy is anything but serene. But how much does the time change really impact our consumption, in light of current market tensions and new technologies?

Geopolitical tensions, climate crisis and the Super El Nino phenomenon continue to weigh on the European energy scenario and promise a complicated winter. Analyzing the long-term trend, the energy benefit of the time change is progressively reducing.

During the seven months of summer time that have just passed, the Italian electricity system benefited from savings estimated by Terna at around 302 million kWh. By moving the clock forward in spring, in fact, the use of artificial lighting in the evening hours was delayed. As highlighted by Terna's memoirs and by union analyses, the blame (or credit) lies with "energy efficiency". If in the twenty-year period 2004-2025 the historical average saving was around 571 million kWh per year (the result of over 12 billion accumulated), the 302 million estimated for 2026 certify that the benefit has almost halved. We are talking about a net decrease of around 270 million kWh per year, which translates into just 1 kWh for every 1.9 kWh that could be cut in the past.

Over the last twenty years, the massive diffusion of LED bulbs and low-consumption lighting systems has reduced the weight of lighting on the total bill. Today, turning on a light bulb costs, in terms of kWh, a fraction compared to the past. Consequently, the "gain" or "loss" generated by the movement of the hands is much less impactful on overall consumption volumes.