An open access power systems model for Southeast Asia shows how cross-border electricity trade could cut costs, boost reliability and speed up the region’s shift away from fossil fuels, according to climate tech non-profit TransitionZero.
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The Asean Power Grid (APG) aims to connect 10 member states into a single system by 2045 to strengthen energy security, enable power exchanges between countries and integrate more renewables. The bloc’s newest member, Timor-Leste did not have data available, the authors said.
Money has started to flow into reviving the long-delayed plan, but actual cross-border projects remain constrained by regulatory, institutional and technical hurdles, leaving progress uneven, a new TransitionZero report found.
Governments are adding more solar and wind, grappling with fuel price shocks and exploring new cross-border cables. Yet they still lack a common, transparent tool to show how these pieces fit together at a regional level, the study suggested.
TransitionZero’s TZ-APG model and its Scenario Builder platform seek to plug this “analytical gap” by giving governments, utilities and financiers an open, system-wide view of how different interconnection and trade options would affect costs, reliability and emissions.
“Different transmission projects, some grid-to-grid, others generator-to-grid, and an enormous number of stakeholders need a common baseline understanding and the ability to query and stress-test decisions,” said Isabella Suarez, TransitionZero’s head of engagement for Southeast Asia.
Scenario Builder provides a no-code, accessible way to model these trade-offs. One concrete application is financial decision-making around interconnectors — helping users decide which lines to prioritise, how much to build and when, and who stands to benefit, Suarez added.
The platform can generate scenarios that map multi-country capital investment needs, simulate power trade flows across the region, and estimate the resulting impacts on system costs and emissions under any configuration users choose to test.
Image: TransitionZero
In the TZ-APG study, the enhanced business-as-usual scenario is the case where only existing cross-border lines are upgraded, with no new regional interconnectors added. This package of transmission upgrades is projected to cost about US$57 billion by 2035.
The Lao PDR–Thailand–Malaysia–Singapore Power Integration Project (LTMS-PIP), which became operational in 2022, marked the first multilateral cross-border electricity trade involving Asean countries. Lao PDR, or the Lao People’s Democratic Republic, is Laos’ official name.
It demonstrated that such trade is technically and commercially feasible, with about 100 megawatts (MW) of renewable hydropower flowing from Laos to Singapore through Thailand and Malaysia using existing interconnections.
But reaching consensus on a more integrated planning approach is neither straightforward nor guaranteed, researchers note, even under a business‑as‑usual grid build‑out. Tensions have emerged, with Thailand reportedly considering exiting the project if its role remains limited to acting as a transit country for electricity from Laos to Singapore. In Indonesia, questions are also being raised over whether mega solar export projects serving Singapore will deliver tangible benefits for the domestic renewable energy industry or its broader energy transition.
Against this backdrop, TZ‑APG offers a way to make trade‑offs more visible, helping governments test who gains, who pays and how different grid choices play out before projects are locked in, it said.
Another TZ-APG case is the regional interconnection scenario, in which 18 priority cross-border projects are built to link electricity networks across the 10 Asean member states. These include transmission lines for large-scale hydropower between Laos and Thailand, an interconnection between Thailand and Malaysia, and Singapore’s proposed new import cables, on top of the existing lines. The grid expansion in this scenario is projected to cost about US$122 billion in transmission investment and upgrades by 2035.
The most ambitious of the four grid scenarios is the “Indonesia Super Grid”. In this case, Indonesia adds four major inter-island transmission links on top of existing and planned Asean interconnectors, enabling large-scale power sharing within the archipelago and with its neighbours, particularly from Kalimantan and Sumatra. This build-out is expected to cost around US$124 billion.
The study described TZ‑APG as a “live” base model that can be updated as grid, demand and policy assumptions shift, rather than a one‑off blueprint.
That flexibility, TransitionZero said, allows policymakers run sensitivity tests on new transmission and import options, probe the “green credentials” of specific interconnectors and, over time, explore the costs of exporting and wheeling power across borders.
