DEN: Sumatra blackout cannot be restored immediately

JAKARTA, KOMPAS.com - The Sumatra blackout incident highlights the significant risks of restoring the power system too quickly without proper synchronisation in a large-scale interconnected grid. National Energy Council (DEN) member M Kholid Syeirazi stated that power system recovery after transmission disruptions must be carried out gradually and with caution to maintain system stability. With an interconnected grid spanning thousands of kilometres and involving numerous power plants and transmission networks, he noted that the relatively swift recovery process demonstrated effective management. ‘Large-scale power system recovery must be carried out with caution,’ Kholid said in a press statement on Tuesday (26/5/2026). ‘The goal is not just to restore power quickly, but to ensure the system returns to normal safely and reliably,’ he added. When a major disturbance occurs and several power plants disconnect from the system, frequency can drop sharply, triggering a domino effect on the power grid. ‘If recovery is done too quickly without proper synchronisation, the risk is that frequency drops again, causing power plants to disconnect once more,’ he explained. ‘That is what must be avoided,’ Kholid added. According to him, an imbalance between supply and demand due to overly aggressive recovery could trigger subsequent blackouts or damage to power generation and transmission equipment. To ensure system safety, thermal power plants such as PLTUs cannot be restored simultaneously. ‘PLTUs cannot be reintegrated into the system all at once,’ he said. ‘There are technical steps that must be followed to ensure power units remain safe and do not encounter issues during synchronisation,’ Kholid added. He stated that in Sumatra’s interconnected system, system stability is the top priority over merely speeding up recovery. ‘In Sumatra’s interconnected system, system stability is the top priority,’ he said. ‘Gradual recovery is necessary to ensure the system fully recovers safely,’ he added. Chief Operating Officer (COO) of Danantara and Head of the State-Owned Enterprises (BUMN) Regulatory Agency Dony Oskaria said an evaluation would be conducted covering business processes, the cause of the blackout, and future mitigation measures. ‘Of course, PLN will conduct a comprehensive review of the process,’ Dony said during an interview at Danantara House in Jakarta on Monday (25/5/2026). ‘We will review the process, including the causes, and future preventive measures,’ he added.