ONS forecasts retreat in the Southeast/Midwest subsystem reservoirs in September

The latest report from the National Electric System Operator (ONS) predicts a drop in the storage of the country’s main reservoir subsystem.

According to the document released this Friday (10), the forecast is that the storage levels of the subsystem in the Southeast/Midwest (SE/CO) will reach an average of 14.9% by the end of September .

Compared to the bulletin released the week before, the decline is 0.3%, when the expectation was to close the month with 15.2% of storage.

The negative numbers come despite the ONS forecasting an increase in rainfall in the region, and having raised the water reserve forecast of the National Integrated System (SIN), which incorporates the country’s four energy subsystems. On the general average, there should be an advance of 0.4% of water stored in the reservoirs.

However, despite the advance in the general average, the water reserve estimates – September 11th to 17th – in the SE/CO and South regions retreated. For the month of September, the expectation is for decreases of 1.2% and 0.4% for the subsystems, respectively.

For the Northeast and North subsystems, growth rates of 4.6% and 5.1% are expected, when compared to the same period of the previous year.

Brazil faces the worst water crisis in river basins in 91 years. As a result, some reservoirs have already reached the minimum level for generating electricity, such as the Furnas hydroelectric plant, which is in a critical situation and registers only 15.8% of the total volume.

The Furnas reservoir is responsible for supplying 17.2% of the entire population of the Southeast and Midwest regions, which concentrate 70% of Brazil’s energy load.

This Friday afternoon, the National Electric System Operator reported that, despite the low percentage, the volume is within enough to maintain the operation, but that it requires attention. The note also says that the SIN has previously operated with volumes below 10%.

“The operation of hydroelectric plants with a storage level of around 10% is technically feasible, with situations recorded in the SIN in which it operated with stored volumes below this value. In this sense, if the reservoirs of the Southeast/Midwest subsystem reach the level of 10% of their storage capacity, this does not compromise the hydraulic governance of the basins that make up the SIN. It is observed, however, that the operation with very low storage values, below 10%, always requires attention, in view of the mechanical demands to which the machine is submitted”, says the note from ONS.