Sumatra Blackout Caused by Cable Failures and Severe Weather, Police Report Explosion Before Incident

The Indonesian National Police’s Criminal Investigation Agency (Bareskrim) has identified three possible causes for the widespread blackout that affected parts of Sumatra. The strongest suspected cause is extreme weather disrupting the electricity transmission network, leading to broken cables. Deputy Chief of Bareskrim, Inspector General Police Nunung Syaifuddin, stated that investigations are ongoing with a joint team from Bareskrim, the Forensic Science Centre (Puslabfor), and state electricity company PT PLN to determine the exact cause. However, initial findings suggest the power outage was triggered by technical issues related to severe weather conditions. “The cause of the transmission cable breaks is still under investigation, with possible factors including mechanical issues from friction and wind impact,” he said on Monday, 25 May 2026. In addition to mechanical factors and wind, police have identified another potential cause: overheating from loose cable connections creating gaps. Extreme weather-induced tugs and swaying of the cables were also cited as possible causes of the transmission network disruption. Nunung explained that the transmission cable disruption led to instability in frequency and voltage, causing a chain reaction of power plant shutdowns and resulting in a widespread blackout across multiple Sumatran regions. The outage affected areas including Aceh, North Sumatra, West Sumatra, Riau, Jambi, and parts of South Sumatra. Despite the transmission network disruption, police confirmed the physical condition of the transmission towers at the initial fault location remained intact with no significant damage. “This suspicion was reinforced by witness statements from locals near the incident site, who reported an explosion shortly before the power outage in the transmission tower area,” he said. On the other hand, Nunung dismissed speculation of sabotage, confirming no evidence of intentional interference in the incident. “To date, we can confirm there is no indication of sabotage or intentional acts in the blackout,” he added.