The National Electric Energy Agency (ANEEL) carried out a new inspection at the Colíder hydroelectric power plant on October 14 and 15 to monitor restoration work on the dam. The inspection was conducted together with the Mato Grosso State Agency for the Regulation of Delegated Public Services (AGER), ANEEL’s partner agency in the state.
ANEEL has been monitoring the Colíder plant closely since the dam’s safety level was raised from “caution” to “alert” on August 14. Since that change, ANEEL and AGER have conducted three inspections to track diagnostic and risk mitigation measures related to the dam’s structure.
According to information disclosed by Eletrobras, the plant’s current owner, the “alert” status was adopted as a precautionary measure following a series of issues with the dam’s drainage system. After acquiring the Colíder plant from Copel on May 30, 2025, Eletrobras began reviewing the facility’s safety conditions and reported that four of the 70 drains responsible for relieving water pressure beneath the dam had been damaged.
On June 14, 2025, Eletrobras was informed of the rupture of one of the drainage system components. The company’s panel of external experts later recommended reducing the water level in the reservoir to preserve the dam’s integrity and allow for a detailed assessment of its condition. Based on these recommendations, Eletrobras instructed Copel, which was still temporarily operating the facility, to lower the reservoir level on August 13 and 14.
Eletrobras stated that it decided to change the dam’s safety level to “alert” as “a precaution and in strict observance of applicable legislation,” adding that the measure activated the company’s Emergency Action Plan to ensure that authorities and nearby communities were properly informed. “These preventive actions reinforce the company’s unwavering and top-priority commitment to the safety of people, the environment, and its facilities,” Eletrobras said.
ANEEL said it continues to conduct weekly reviews with Eletrobras to ensure progress on safety restoration efforts. The agency said it is “demanding concrete actions to restore the safety level to normal conditions, in order to guarantee the safety of people and the asset’s structures.”
The Colíder plant had already been scheduled for an on-site inspection in the second half of 2025 as part of ANEEL’s annual inspection plan. The goal was to assess plant performance, the dam’s safety level, and compliance with the National Dam Safety Policy (PNSB), established by Law No. 12,334/2010.
The Colíder hydroelectric power plant is located on the Teles Pires River in northern Mato Grosso. It was built by Copel between 2011 and 2019 and operated by the company until May 2025, when it was acquired by Eletrobras. The plant has an installed capacity of 300MW, representing about 0.5% of Eletrobras’ total assets.
