Indonesia's Blackouts Expose an 853MW Rooftop Solar Deficit
Repeated power outages across Sumatra and the Java-Madura-Bali grid have thrown into relief how far behind Indonesia sits on distributed solar deployment, according to a report published on Tuesday (2026-06-30) by the Institute for Energy Economics and Financial Analysis.5
That gap is stark by regional comparison. Indonesia had installed 853 megawatts of rooftop solar capacity by 2025 — against Vietnam's 6.9 gigawatts, Thailand's 3.6 gigawatts, and Malaysia's 1.8 gigawatts, IEEFA data show. The shortfall is not simply a matter of ambition; it reflects grid architecture, regulatory bottlenecks and the dominant position of state utility PLN, which controls generation, transmission and distribution across the archipelago.5,4
The JAMALI grid — Java, Madura and Bali — carries roughly 60% of Indonesia's electricity load and has long been the system's most congested artery. Sumatra, meanwhile, runs on a separate island grid with its own interconnection limits. The outages that prompted IEEFA's report were not caused by a single event but by accumulated transmission stress as demand growth outpaced infrastructure investment.5,4
Distributed rooftop solar, paired with battery storage, is one response to that structural vulnerability. It reduces transmission losses, pushes generation closer to load, and provides some resilience when the main grid falters. Indonesia's current 853MW base offers little of that buffer at national scale.5
The regulatory environment has not helped. PLN's integrated monopoly structure has historically given it incentives to defend its own generation assets rather than facilitate net-metering arrangements that would benefit rooftop solar owners. Grid connection approvals have been slow and export tariffs for excess rooftop generation have been set below levels that would attract household or commercial investment.4
The irony is that Indonesia is simultaneously being courted as a solar exporter. Singapore has awarded conditional approvals to import up to 3.4 gigawatts of firmed solar from Indonesia, according to Mott MacDonald data, a volume that would by itself increase the region's installed solar capacity by more than 70%. Those projects, targeting cross-border subsea cable transmission, remain in development and face financing and procurement hurdles — booking deposits for subsea cables alone can run to 10-20% of total cable value, Mott MacDonald noted.3
The domestic picture sits in the wider context of accelerating Southeast Asian power demand. Data centres, electric vehicles and green industrial parks are expected to push regional power consumption up by more than 100 terawatt-hours over the next three to four years, requiring investments exceeding $200 billion, according to the 2026 Southeast Asia Green Economy Report from Bain & Company and Standard Chartered. Indonesia, as the region's most populous economy, would account for a significant portion of that demand growth.1,2
Yet only around 60% of the $540 billion in announced green investments across the region's power and EV supply chains is considered likely to proceed under current conditions, the same report found. Financing constraints and regulatory uncertainty are cited as the main barriers — the same barriers that have kept Indonesia's rooftop solar capacity so far below peers despite abundant solar resource.2
PLN has said it plans to increase renewable capacity, and the government has set a target of reaching 23% renewables in the energy mix by 2025, a target widely acknowledged to have been missed. New grid investment is underway, but building out transmission across a 17,000-island archipelago is a fundamentally different engineering and financing challenge than the compact grid upgrades that have driven rooftop solar adoption in Vietnam and Thailand.4
The IEEFA report does not name a specific deployment target for distributed solar, but the implied argument is clear: battery-backed rooftop generation could shore up grid resilience in ways that central-plant additions alone cannot, particularly given the transmission losses and congestion that contributed to the recent blackouts. Whether Indonesian regulators act on that logic — or whether PLN's institutional incentives continue to slow rooftop uptake — will determine how much of the $200 billion regional investment wave reaches distributed rather than utility-scale assets.5,2