North Sumatra’s electricity transmission network is facing a crisis of reliability after two major infrastructure failures in less than a month, prompting the Institute for Essential Services Reform (IESR) to call for a sweeping government review. The incidents, which involved the collapse of 12 transmission towers, have sparked concerns about whether Indonesia’s grid can handle future renewable energy integration amid increasingly extreme weather.
Why the Transmission Grid Is Failing
The most recent structural failures occurred on June 4, 2026, impacting two key corridors in North Sumatra. According to the Institute for Essential Services Reform (IESR), three towers on the 275-kV Galang–Simangkuk extra-high-voltage line collapsed, while two others suffered structural deformation. On the same day, six towers on the 150-kV Tebing Tinggi–Sei Rotan line fell, with an additional tower bending under pressure.
These events followed a massive, widespread power outage that struck eight provinces across Sumatra on May 22, 2026. Power was not fully restored to the affected regions until May 24, 2026. While extreme weather—specifically heavy rainfall and strong winds—has been cited as the trigger, IESR Chief Executive Officer Fabby Tumiwa argues that weather alone is an insufficient explanation for the scale of the damage. Transmission towers are engineered to withstand the heavy rain, lightning, and high winds typical of the Indonesian climate, suggesting that deeper vulnerabilities exist within the current infrastructure.
The Threat to Renewable Energy Goals
The instability of the transmission grid poses a significant hurdle for Indonesia’s energy transition. The country has ambitious plans to integrate tens of gigawatts of solar energy in the coming years. However, as noted by PV Magazine Australia, these projects are likely to struggle if the national transmission framework remains unable to withstand severe climate conditions.
The grid’s inability to maintain steady service during weather events suggests the infrastructure is not currently prepared for the complexities of a modernized, renewable-heavy energy system. Industry analysts emphasize that strengthening the grid will require substantial investment in both transmission infrastructure and climate-resilience measures to prevent future systemic collapses.
What Happens Next for Grid Resilience
The Indonesian government is under pressure to move beyond initial investigations. Following the May blackout, Vice Minister of Energy and Mineral Resources Yuliot announced that the government was preparing mitigation measures to prevent further outages. However, the recurrence of these failures in June has intensified calls from the IESR for a comprehensive, systemic review of the national transmission network.
Key Takeaways
- Recent Failures: A total of 12 transmission towers collapsed in North Sumatra during early June 2026, following a separate, widespread blackout across eight provinces in late May 2026.
- Infrastructure Stress: The 275-kV Galang–Simangkuk line, which only became operational in 2019, was among the infrastructure damaged during the June 4 events.
- Expert Stance: The IESR disputes the idea that weather is the sole cause of these failures, instead pointing to broader issues with grid resilience and design standards.
- Renewable Impact: Experts warn that the failure to secure transmission infrastructure could jeopardize Indonesia’s long-term plans to integrate large-scale solar energy projects.
As the country faces increasingly frequent extreme weather linked to climate change, the resilience of its power infrastructure remains a critical point of concern for both policymakers and energy stakeholders. Future stability will depend on whether the government’s upcoming mitigation efforts can address the structural weaknesses exposed by these back-to-back failures.