Brazil has recorded extremely high temperatures throughout the winter, which ended on Saturday (23). In recent weeks, thermometers have reached 40º in some regions of the country. But how does this influence the photovoltaic sector?
One of the effects of the hot climate is the increase in electricity consumption, due to the greater use of refrigerators and air conditioning.
According to the ONS (National Electric System Operator), national electricity demand is expected to increase by 5,8% (75.234 MWmed) in September, compared to the same period in 2022.
“The rise in average temperatures, a phenomenon recorded in the main Brazilian cities, is one of the reasons that justify this behavior,” said the organization in a bulletin released to the press.
The Southeast-Central-West region, which concentrates the largest electricity consumption in the country, is expected to a variation of 6,1% (42.756 MWmed) this month. In the South and Northeast, increases of 3,8% (12.421 MWmed) and 4,2% (12.350 MWmed) are expected, respectively.
In the North, the acceleration is more significant, with 10,6% (7.707 MWmed), “a situation also related to the resumption of free consumer activities in the region”.
“The load growth forecast for September is the highest in recent months, a reflection of the more intense heat and also a more heated economy. In of operations and meeting demand, we remain prepared to serve Brazilian society. The system is robust, safe and the scenario is favorable”, says Luiz Carlos Ciocchi, general director of the ONS.
Peak consumption occurs in the middle of the afternoon, between 14pm and 15pm, when the heat is most intense and the air conditioning is operating at maximum. On very hot days, the load can exceed 90 GW on average.
Despite the blackout on August 15, the ONS guarantees that the SIN (National Interconnected System) is prepared to meet this increase in demand, thanks to the good supply of hydroelectric energy and renewable sources.
As 52% of the matrix is made up of hydroelectric plants, the level of the reservoirs represents the energy stock. According to the ONS, the EAR (Stored Energy) is above 70% in the Southeast/Mid-West subsystem (72,6%), in the North (73,7%) and in the South (85,2%). In the Northeast, capacity is 62,2%.
“The typically dry period is close to ending, which makes the results more relevant,” says the ONS. The wet period starts in December and lasts until April.
But how does this influence the photovoltaic sector?
Thermal discomfort and the consequent increase in energy consumption awaken consumers' interest in solutions that reduce electricity bills, boosting sales in the solar energy retail market, with emphasis on the residential and commercial sectors, whose consumption grew by 6,6. 4,2% and 2023% in the second quarter of XNUMX, according to EPE (Energy Research Company).
Furthermore, greater solar irradiation favors increased production of electrical energy by the photovoltaic source. However, very high temperatures can compromise the efficiency of the modules due to the equipment heating up at a stage higher than that planned for optimal operation.
Therefore, it is important that integrators are clear about this situation so that they can explain it to the customer in case of complaints about low performance.
“The relationship between temperature and the electrical variables of a photovoltaic generation system must be clear to the integrator. The voltage and power of a string are greatly influenced by temperature, on days with very high temperatures, voltage and power tend to drop proportionally based on coefficients that are present in the modules’ data sheets”, explains the engineer Geraldo Silveira, specialist in photovoltaic systems.
“This means that there may be a drop in generation on days with very high temperatures and the customer may understand this as a drop in the performance of their system, but in fact it is a reduction in generation due to the influence of the high temperature, already expected due to this well-known behavior of the modules in relation to the ambient temperature and on their surface”, adds Silveira.
An answer
Here in the South, the reduction in photovoltaic solar energy generation has been happening since September 2020, due to the drought, which despite the dry weather, we had more days with clouds than with sun. In 2023, we have also had few sunny days, now due to frequent rains and cloudy days. We have recorded drops in solar generation in almost every month, in all regions of RS.