A widespread power outage hit Tbilisi and several other Georgian cities on Tuesday evening, marking the third major disruption to the country's electricity grid since late July. The causes of the two previous blackouts remain under investigation by Georgia's State Security Service.

According to local media and reports from social media users, electricity began to fail at around 8:10 p.m. local time. Power outages were reported across parts of Tbilisi, Akhalkalaki, Akhaltsikhe and several other towns.

As of publication, neither the authorities nor the national grid operator had disclosed the cause of the latest outage or the full extent of the disruption.

The incident is the third large-scale blackout in less than two weeks. Previous outages occurred on July 24 and 25, when electricity supplies were also disrupted in Tbilisi and other parts of the country. Restoring power took several hours on both occasions.

Following the second outage, Levan Mebonia, director of the Enguri Hydropower Plant, said the disruption had been triggered by the failure of the 500-kilovolt Imereti high-voltage transmission line. According to Mebonia, the line carried a significant share of the Enguri HPP's electricity toward Zestaponi, and its shutdown disrupted the operation of the national power system, triggering a cascading failure. Electricity supplies were fully restored by 10:15 a.m. the following day.

The Georgian State Electrosystem (GSE), which operates the country's transmission network, has not identified the definitive cause of the July outages, saying the investigation is still ongoing.

The repeated blackouts have also drawn the attention of Georgia's State Security Service. Following the July 24 and 25 incidents, the agency launched a criminal investigation under Article 318 of the Criminal Code, which covers disruption of critical infrastructure posing a threat to state interests. Investigators are examining, among other possibilities, whether sabotage may have played a role, although no evidence supporting that theory has been presented so far.

The series of outages has renewed concerns about the resilience of Georgia's electricity grid. The Imereti transmission line is part of the country's 500-kilovolt backbone network linking the Enguri Hydropower Plant and other generating facilities in western Georgia with Tbilisi and the eastern regions. In one of its earlier reports, GSE noted that during periods of peak demand, the line carries the bulk of electricity flows from west to east, while the network's redundancy is limited under heavy load.

To reduce such risks, Georgia is implementing its Energy Network Improvement Programme. By 2028, the government plans to build and modernize seven substations and more than 540 kilometers (335 miles) of transmission lines. Total investment in the project is estimated at approximately €270 million.