The Tanzania Electric Supply Company (TANESCO) and the government have explained that faults in parts of the electricity transmission and generation systems triggered power plants’ fail-safe mechanisms, leading to a nationwide blackout on June 27, 2026. The outage began at around 6:59 p.m. and power was fully restored by midnight.
Speaking during a visit to the Ubungo Control Centre, the national grid’s main control office, TANESCO Managing Director Lazaro Twange said the utility is continuing to investigate the fault.
“What happened yesterday is that three of our transmission lines experienced problems, and one of our power generation stations also developed a fault. Unfortunately, this caused a system failure that led to the national grid going offline,” Twange explained.
“These systems are also equipped with self-protection mechanisms. Therefore, under certain circumstances, the infrastructure may automatically protect itself to prevent damage,” he added.
However, Twange emphasized that the incident was unfortunate and is not something that happens frequently.
“These are events that do not occur often. We have many control systems in place, but these are installations that are subject to risk sometimes,” he said.
The March 2026 EWURA report shows that the country’s electricity transmission network comprises 72 substations and spans 8,303.87 km of high-voltage transmission lines across four voltage levels: 1,524.75 km of 400 kV lines, 3,860.95 km of 220 kV lines, 2,335.17 km of 132 kV lines, and 583 km of 66 kV lines.
The report also notes that substation capacity increased from 55 substations with a total capacity of 4,356 MVA in the 2018/19 financial year to 72 substations with a combined capacity of 10,225.8 MVA in 2025/26, a notable increase in capacity compared to a number of stations.
The Power System Master Plan 2024 Update indicates that Tanzania’s national electricity grid is designed to meet the N-1 criterion-the principle that if any single component of the grid, such as a transmission line or transformer, fails, the rest of the system should absorb the loss and continue supplying power without interruption. However, the master plan also notes that there were existing breaches of this criterion that were planned to be fully addressed by 2050.
The June 27 incident suggests a critical system failure in which at least four components were affected. Permanent Secretary at the Ministry of Energy, Felchesmi Mramba, noted that the incident was a fast chain reaction that couldn’t be stopped.
“Preliminary information shows that faults in transmission lines heading to Dodoma were the first to occur, and their effect fed into another line running from Chalinze to Dar es Salaam. Remember, this is a chain reaction that happens within a very short time; once it starts, there is no way to stop it,” Mramba said.
While TANESCO’s Managing Director said teams of engineers had already been dispatched to the affected transmission lines and power generation stations, the government has also formed an investigation team to determine the cause of the outage and draw lessons from the incident.
The Minister of Energy, Deogratius Ndenjembi, instructed the Permanent Secretary of the Ministry of Energy to establish a team of experts comprising TANESCO officials, ministry personnel, and representatives from the security and defense agencies to investigate what happened and ensure that such an incident does not happen again.
“The most important thing is to learn from what happened yesterday so that we can take prompt action to prevent the country from experiencing a nationwide blackout at the same time again,” Ndenjembi said.
The minister also said the ministry expects to receive a preliminary report from TANESCO on June 29, 2026, and will await a more comprehensive report once the investigation team completes its work.
“Another thing we have instructed is to ensure that our national grid network is able to shed excess load when one section becomes overloaded, so that if one part fails, it does not cause all regions of the country to lose electricity simultaneously,” he said.
For its part, TANESCO apologized to electricity consumers for the inconvenience caused and said it is continuing efforts to strengthen and improve the national power grid infrastructure.
