Power outage in Sumatra: PLN says 8.3 million customers back on supply

PLN (Persero) said that 8.35 million out of 13.1 million customers in Sumatra have had their electricity supply restored. The data reflects the progress of restoring Sumatra’s power grid as of 10:00 WIB on Saturday, 23 May 2026. “The recovery process is continuing and we are all out so that power to the community can be restored gradually and safely,” PLN Chief Executive Darmawan Prasodjo said at a press conference at PLN’s office on Saturday. PLN has also restored 157 substations out of 176 that were affected. “Currently, all PLN personnel and technical teams are working full-time in the field,” he added. The outage in Sumatra was caused by a fault on the 275 kV Ultra-High Voltage transmission line (SUTET) Muara Bungo, Sungai Rumbai, Jambi. The disturbance is suspected to have been triggered by bad weather in the area. Although it occurred at a single point, the fault caused a domino effect, with several power plants in Sumatra tripping. PLN then focused on re-energising a number of power plants, including hydro, gas, and steam-fired units. Restoring power to steam-fired plants takes longer, as it requires heating water; “thermals such as PLTU require between 15 and 20 hours from start-up, synchronization to full operation,” Darmawan explained.