Lettuce production under photovoltaic panels delivered surprising results at the Chair in Renewable Energies (CER) of the University of Évora, at the Mitra campus. The project, carried out within the scope of CER in collaboration with the Mediterranean Institute for Agriculture, Environment and Development (MED), showed that partial shading from solar panels almost doubled lettuce yields during the summer, compared to plants grown in full sun.
The research took place between June and August and involved visiting researchers Mireia Correll (Universidad de Sevilla) and David Perez (Universidad Politécnica de Madrid), in cooperation with teams from the University of Évora.
The study compared lettuce growth under two conditions: shaded by photovoltaic panels and fully exposed to the sun, in a summer when temperatures frequently exceeded 40 ºC. Plants were irrigated using a drip system, with different water flow rates tested in both scenarios.
The results were clear: some lettuces grown under the solar panels exceeded 500 grams in just 30 days, while those exposed to full sun showed limited growth, affected by excessive heat and direct radiation. In addition to higher yields, water use proved more efficient, and quality was superior — lettuces were more tender and flavorful.
The harvested lettuces were distributed among the university community at the Mitra campus. Preliminary analysis further suggests that this practice could extend the lettuce growing season in the Alentejo, allowing for high levels of yield and quality even during the hottest months of the year.
