EN 
PT_BR 
The level of the reservoirs in the Southeast/Mid-West subsystem, which concentrates more than 70% of all water stored in the country, worsened even further in September due to the effects of the biggest drought in the last 91 years.
This Tuesday (14), the storage percentage of the hydroelectric plants that make up the two Brazilian regions reached the mark of 18.58% and in some of them the rates are in an increasingly critical state.
This is the case of Ilha Solteira, the largest plant in São Paulo and the third largest in the country, which operates this Tuesday with just 1.82% of its capacity. In August, the reservoir level was at 36%. Less than two weeks ago, volume remained at around 10%.
The Três Irmãos plant, in the Tietê River basin, also in São Paulo, follows the same path and, today (14), has a volume of 4.16%. In the same period last year, the reservoir level was at 62%. In August this year, the level was 39%.
Other reservoirs
In addition to Ilha Solteira and Três Irmãos, other hydro plants that supply the Southeast/Central West subsystem also record worrying volumes. The Marimbondo and Itumbiara basins, for example, have already operated with less than 10% of capacity: 9.3% and 9.77%, respectively.
Just over a month ago, the situation in both projects was already very serious, but it got worse with the lack of rain. On August 3, the rainfall volume in Maribondo was 16.13%, while that in Itumbiara was 12.09%.
The scenario also worsened in other hydroelectric plants. Two other examples of reduction in storage capacity are Águas Vermelhas, Nova Ponte and Emborcação, which operate in August with 12.91%, 13.36% and 14.69% of useful volume, respectively. Today, the capacity of each of them is less than 12%.
Plants with less capacity in operation in the Southeast/Central West subsystem:
- Ilha Solteira: 1,82%
- Three Brothers: 4,82%
- Marimbondo: 9,30%
- Itumbiara: 9,77%
- Capsizing: 10,82%
- Águas Vermelhas: 11,12%
- New Bridge: 11,36%
- Furnas: 15,37%
- M. Moraes: 15,63%
- São Simão: 15,83%
What does the ONS say?
In a note, the Operator informed that the operation of hydroelectric plants with a storage level of around 10% is technically viable and highlighted that there are even records of situations in which the SIN (National Interconnected System) operated with volumes lower than this.
“In this sense, if the reservoirs in the Southeast/Central-West 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 should be noted, however, that operation with very low storage values, lower than 10%, always requires attention, given the mechanical stresses to which the machine is subjected”, points out the document.
