Análise do impacto das restrições de rede no aumento da temperatura e degradação de módulos fotovoltaicos: estudo de caso em uma usina de geração centralizada

Abstract

The accelerated growth of utility-scale photovoltaic solar generation in Brazil has intensified theoccurrence of operational constraints imposed by the power system, commonly referred to ascurtailment. These constraints, mainly determined by the Brazilian National System Operator(ONS), limit the power injected by power plants even under favorable irradiance conditions andhave traditionally been treated as strictly energy and economic losses, without considering theirpotential physical effects on photovoltaic modules. This study investigates the impact of gridrelated operational constraints on the thermal behavior and degradation of photovoltaic modulesin a utility-scale solar power plant located in Northeastern Brazil, based on real operationaldata obtained from the SCADA system, covering the period from 2022 to 2025. Initially, thedifferent types of operational constraints are characterized, with emphasis on curtailment andthe resulting deviation from the modules’ maximum power point. Subsequently, the thermalpenalty associated with these operating regimes is evaluated through the variable ∆T, definedas the difference between module temperature and ambient temperature. The results show thatoperation under curtailment is associated with a systematic increase in the average operatingtemperature of the modules, reflected in ∆T distributions shifted toward higher values whencompared to normal operation. To quantify the impact of this thermal increase on moduledegradation, the Arrhenius model is applied considering different activation energy values. Theresulting degradation acceleration factors range from 1,79 to 2,49, leading to corrected annualdegradation rates between 0,54% and 0,62%, compared to a reference rate of 0,45% per year,which corresponds to additional degradation increments on the order of 0,09% to 0,17% peryear associated with curtailment. Lifetime projections indicate that this accumulated thermaleffect may anticipate typical power loss milestones by approximately 5 to 8 years, dependingon the curtailment scenario and the activation energy considered, when compared to standardmanufacturer warranties. These results demonstrate that curtailment should not be interpretedsolely as a loss of marketable energy, but also as a relevant source of thermal stress, with directimplications for the reliability and long-term lifespan of photovoltaic assets