Coincidence of Photovoltaic Electric Generation During Heat Waves: An Example Analysis for Northern Italy

Given the increasing life-threatening events of heat waves associated with possible power outage scenarios, the question emerges: how might rooftop PV help address heat wave impacts? In this study, we explore the coincidence of high solar irradiance on the hottest days that may allow substantial electrical generation during heat waves. PV output is somewhat adversely impacted by high array temperatures, but this can be accounted for in a sophisticated simulation of PV performance. Historic weather patterns were examined for Milan, Italy for 59 years from 1965 to 2023 to locate maximum annual heat waves as well as solar PV performance on the hottest days for each year. Hourly weather data was obtained from the Malpensa airport weather station [1]. Patterns and trends for the annual hottest days, coincident hourly and daily PV output are evaluated. Accordingly, we compared the coincidence of output from a 6 kW PV array during the periods of the hottest temperature, both on an hourly and daily basis. The assessment serves as an example of how such an analysis can be conducted for varied locations and how site PV might provide enhanced hot weather resiliency for future buildings and occupants.