Lightning Strike and Tree Damage Trigger Widespread Sumatra Power Outage

A widespread power outage across Sumatra was triggered by a significant disruption to the 275 kV Extra High Voltage Transmission Line (SUTET) connecting Lubuk Linggau and Lahat in South Sumatra. The massive blackout, which plunged multiple provinces into darkness, began on Friday evening, May 22, 2026. PT PLN (Persero), Indonesia's state electricity company, is investigating the incident.

Initial findings point to a combination of factors, including lightning strikes and damage caused by falling trees, as the primary causes of the transmission line failure. This disruption led to a severe imbalance in the interconnected power system, cascading across Sumatra. The affected areas include South Sumatra, Jambi, Bengkulu, Lampung, West Sumatra, Riau, North Sumatra, and Aceh, impacting millions of residents.

PLN President Director Darmawan Prasodjo explained that the disturbance originated in the Muara Bungo–Sungai Rumbai 275 kV transmission line in Jambi. This incident caused a domino effect throughout the island's power grid. In some regions, the sudden loss of load resulted in an excess of power, causing generators to automatically disconnect. Conversely, other areas experienced a deficit as generators tripped offline, leading to a widespread failure.

Darmawan stated that the initial indication is that weather-related issues caused the transmission line to disconnect from the Sumatera grid. The subsequent system shock led to a chain reaction, affecting the power supply from Jambi all the way to Aceh. PLN is working to restore power and is assessing the full extent of the damage to prevent future occurrences.