From Vision to Voltage with TZ-APG

The energy transition imperative is bringing Southeast Asian countries closer together. Over the past three years, regional cooperation on grid integration and cross-border electricity trade has seen more progress than ever before, as the region looks inward, and member states actively consider various strategies for enhanced energy security and better, sustained access to low-carbon electricity. This includes the actual functioning of the multilateral trading scheme between Lao PDR, Thailand, Malaysia, and Singapore from June 2022; Malaysia’s establishment of the cross-border green electricity trading platform in October 2023; and Singapore’s ongoing pursuit of large-scale renewable energy projects abroad to be linked by subsea interconnectors carrying these electrons home, to name a few.

Underpinning these efforts is the region’s fast-growing demand for clean electricity. Countries in the region are competing aggressively over big-ticket foreign direct investments in sectors ranging from electronics and semiconductors to data centres, all of which have hard requirements for low-carbon electricity access. While nine out of the ten ASEAN member states – the exception being the Philippines – have pledged to achieve net zero emissions, the decarbonisation gap in the power sector remains wide. Equally important, countries are also exploring indigenous renewable energy sources and power imports as a supply diversification strategy to counter the risk of fossil fuels cost and supply volatility in the long run.

As a result, the conventional practice of importing fossil fuels for localised power generation and demand-supply balance is being revisited. Some planners are incorporating new elements into national power plans, such as new cross-border transmission lines or higher import targets, all of which challenge our understanding of how national power systems may evolve and interact with one another in the future. Existing models and studies on regional grid connectivity, commonly referred to as the ASEAN Power Grid, have become less helpful as points of reference amidst this fast-evolving landscape.

At the same time, reaching a consensus on this new systems planning approach is neither straightforward nor guaranteed. We’re already seeing some tension simmering in the region. Thailand reportedly wanted out of the Lao PDR-Thailand-Malaysia-Singapore Power Integration Project (LTMS-PIP) if its role would remain as just a carrier of electricity from Lao PDR to Singapore; it needed the hydropower for itself, according to then-prime minister Srettha Thavisin. With Thai corporates and its utility company Electricity Generating Authority of Thailand having invested in grid connections with Lao PDR for decades, the entry of a third user complicates this commercial dynamic. In another corner of Southeast Asia, concerns are also being raised in Indonesia as to whether the mega solar power projects designated for Singapore would bring any benefit to their domestic renewable energy industry or its broader energy transition.

There’s a need for better, more transparent energy systems modelling and analysis on what regional grid integration means and how it could work for each country and stakeholder.

TransitionZero’s ASEAN Power Grid model, or TZ-APG, was developed to fill this gap. It aims to address some of the most recent and pressing questions on regional grid planning today, including:

• What are the net gains to each country, or each region within a country, under different grid expansion scenarios? What would the conditions underlying these impacts be?
• To what extent can a regional grid foster higher renewable energy penetration, and limit the build-out and use of fossil fuels?
• Which transmission corridors would be the most catalytic for regional decarbonisation?
• What broader impact could Singapore’s subsea cable projects have for regional connectivity?
• How should we view the long-term role of interconnectors in an era of accelerated technological change and shifting policy priorities?

In the accompanying report for version 1 of TZ-APG, titled 'From Vision to Voltage: Open Source Modelling of the ASEAN Power Grid', we provide key insights investigating these critical questions.

Introducing the TZ-APG model

TZ-APG is the first open source power systems model covering 10 ASEAN countries, with a focus on regional transmission. It is built on PyPSA with a best-in-class spatial resolution which supports a 24-node model where each country is represented by at least one node. Larger markets such as Malaysia, the Philippines, Thailand, and Vietnam are represented by three nodes each, while Indonesia is split into seven nodes corresponding to its main islands. This level of granularity supports modelling and analysis down to the sub-national level.

As a grid dispatch model, TZ-APG optimises both capacity expansion and operation of power plants, storage, and transmission to meet projected electricity demand at each node. Two-hour block temporal representation is used to ensure that power demand is matched with adequate supply at every two-hour interval throughout the modelling period. The value of power systems modelling lies in its ability to simulate the availability, or dispatchability, of different generation sources, including variable renewable energy, and the use of transmission across nodes to facilitate it. TZ-APG illustrates how these sources can be optimally integrated into the power system to serve demand at a specific point in time.

All input data and constraints can be revised, updated, or expanded in future iterations of the model. In this first iteration, TZ-APG v1, we opted for the following design and key constraints:

Open

TZ-APG is a flexible, scalable, and replicable modelling tool that can and will be continuously updated to respond and adapt to new policy and research questions.

For instance, while we were developing TZ-APG, Singapore revised its 2035 import target upwards to 6GW and gave the first official greenlight to the Sun Cable project meant to deliver solar power from Australia over a 4,300km subsea cable. Such new elements can be incorporated in the TZ-APG model. If you’re a modeller, you can download the inputs and models to answer your research questions today.

In the first iteration, the four grid scenarios unlock a deeper understanding of system development and performance across different grid expansion pathways. TZ-APG v1 allows us to offer stakeholders unique insights into regional transmission in Southeast Asia and its transformative potential.

Curious about what these scenarios reveal? Dive into the second article in this series.

Want to know more about the relevance of TZ-APG v1 to the regional and thematic developments in the region? Read our blog 'Modelling ASEAN cross-border transmission with TZ-APG' and download the report 'From Vision to Voltage: Open Source Modelling of the ASEAN Power Grid'.