Photovoltaic Panels and Extreme Heat: How Network Load is Reduced

Italian summers are heating up, and air conditioners are staying on for longer, but photovoltaic panels installed on residential rooftops could absorb a significant part of the resulting increase in electricity consumption. This is supported by a study published in the journal Environmental Research: Energy, authored by economists Lucia Piazza from Ca' Foscari University of Venice, and Francesco Pietro Colelli, affiliated with both Ca' Foscari and the Euro-Mediterranean Centre on Climate Change (CMCC).

The two researchers cross-referenced electricity consumption data collected by the Regulatory Authority for Energy, Networks and Environment (ARERA) with statistics from the Energy Services Manager, CMIP6 climate projections, and photovoltaic development scenarios elaborated by Terna. The goal was to quantify how much domestic electricity consumption for cooling will grow in a rapidly warming country, and how much of this increase can be absorbed by self-produced energy.

Estimates indicate that climate warming could increase domestic electricity consumption for cooling by 2–3 TWh per year by 2050, an amount equal to about 5% of the residential consumption recorded in 2023, which stands at 69 TWh. Without an acceleration in photovoltaic adoption, the additional demand linked to heat would rise to around 2.8 TWh, which is 44% more than historical consumption related to domestic thermal comfort.

A reduction in consumption of up to 68% on the hottest days, thanks to solar panels. However, the authors calculate that a spread of panels in line with national objectives would change the scenario. Currently, about 6% of Italian households have a rooftop system, a share that could rise to 14-15% by 2030 and 22-24% by 2050. In this scenario, self-production would absorb almost half of the additional load imposed by global warming on the national electricity grid.

The most striking data concerns the behavior of homes already equipped with photovoltaic systems. On days when temperatures exceed 30°C, and air conditioners work more intensively, these homes can reduce electricity withdrawals from the grid by up to 68%, thanks to the coincidence between peak sunlight hours and peak cooling demand. In the summer months, the reduction in demand during peak hours fluctuates between 15% and 18%.

The study also signals a problem of territorial inequality. Northern regions and islands, where the spread of domestic photovoltaics is already higher, are those that could benefit the most from self-production. Large urban areas in the Center-South, on the other hand, are in what the researchers define as double vulnerability: they will be among the areas most affected by rising temperatures, yet currently have relatively low penetration of solar panels.

Cities identified as main poles of growth in electricity demand for cooling include Rome, Naples, Milan, and Palermo, with the most significant increases expected along the Tyrrhenian coast of Central Italy and in the Roman and Neapolitan areas. Sicily and Veneto, thanks to a greater presence of plants, show a superior capacity to absorb the new energy needs generated by heatwaves.

For Piazza and Colelli, photovoltaics thus become a concrete tool for adapting to climate change. The challenge, according to the two researchers, is to build targeted policies in large cities and in regions where heat will grow more rapidly: specific incentives and building regulations could prevent areas already more exposed to Mediterranean summers from being excluded from the benefits of energy self-production.