Photo 1. Group photo of the ASEAN Regional Capacity Building Workshop. 

Heads of ASEAN Power Utilities/Authorities (HAPUA), in collaboration with the PT PLN (Persero) and the ASEAN Centre for Energy (ACE), successfully held the Capacity Building Workshop on Available Transmission Capacity (ATC) from 27-28 August 2025 in Jakarta, Indonesia. The workshop brought together a total of 80 representatives from ASEAN Member States (AMS) especially from the utilities and electricity regulators to strengthen the technical knowledge related to ATC. 

Supported by the Southeast Asia Energy Transition Partnership of the United Nations Office for Project Services (ETP-UNOPS) and the Ministry of Foreign Affairs and Trade (MFAT) of New Zealand, the programme aimed to enhance the participants’ understanding of ATC concepts, methodologies, and practical applications in the planning and operation of cross-border electricity trade. The workshop was also conducted in the interest of supporting the implementation of the ASEAN Plan of Action for Energy Cooperation (APAEC) Programme Area No. 1: ASEAN Power Grid.  

Photo 2. Opening remarks by Endah Cahyaningrum, General Manager of PLN Corporate University (left); H.E. Joanna Jane Anderson, Ambassador of New Zealand to ASEAN (center); and Beni Suryadi, Senior Manager of the ASEAN Plan of Action for Energy Cooperation (APAEC) & Strategic Partnership (right). 

The first day of the workshop opened with the welcoming remarks from Endah Cahyaningrum, General Manager of PLN Corporate University, started her remark by welcoming all delegates and highlighted the importance of building both technical skills and practical understanding, as well as the value of collaboration in advancing the ASEAN Power Grid vision. H.E. Joanna Jane Anderson, Ambassador of New Zealand to ASEAN, continued by expressing New Zealand’s enthusiasm in supporting ASEAN’s energy transition and reaffirming the country’s commitment as a long-term partner for renewable energy and regional energy security. Beni Suryadi, Senior Manager of the ASEAN Plan of Action for Energy Cooperation (APAEC) and Strategic Partnership, closed the remarks by expressing appreciation to PLN, HAPUA, and partners for their collaboration, emphasising that ATC is not only a technical concept but also the backbone for reliable operations, power exchange, and renewable energy integration. 

Photo 3. Jonathan Hedgecock (left) and Dr. Graeme Chown (right) delivered presentations on ATC concepts and simulation exercises during the workshop. 

The first presentation was delivered by Jonathan Hedgecock of Ricardo Consulting, setting the scene by explaining the significance of Available Transfer Capability (ATC) for power delivery and cross-border electricity trading in ASEAN, particularly as the growing share of renewable energy. The session emphasised ATC’s role in ensuring reliable daily operations and facilitating bilateral electricity trade, while also contrasting the current limited interconnections with ASEAN’s longer-term vision. By 2030 and beyond, the region aims to develop a broader network of interconnections, with 18 priority projects identified in the ASEAN Interconnection Masterplan Study (AIMS) III. These projects are expected to pave the way for deeper regional integration and more robust electricity trade. ATC will be crucial to maximise the use of these future interconnectors, supporting both bilateral and multilateral exchanges, while also serving as a fundamental tool for congestion management to safeguard system reliability and market efficiency. 

Photo 4. Active interaction from the participants enriched the discussion and knowledge exchange. 

This was followed by a detailed session on the methods and components of ATC calculation, which introduced participants to key technical aspects such as system studies, remedial measures, and considerations for interconnected networks. The session also addressed the concept of Transmission Reliability Margin (TRM), highlighting its relation to system frequency response, renewable energy integration, coordination across control areas, and its role in ensuring secure operations. To implement the concepts, participants participated in PowerWorld simulation exercises, running steady state studies to determine Total Transfer Capability and dynamic studies to calculate Transmission Reliability Margin. 

Photo 5. Participants taking part in hands-on simulation activities and engaging in interactive discussions to exchange perspectives and insights. 

The second day of the workshop began with a presentation by a representative from Ricardo, Dr. Graeme Chown, presenting the technical factors in calculating Net Transfer Capability (NTC) and Available Transfer Capability (ATC). The session explored several aspects including generation shift factors, remedial action schemes, capacity reservation, project progress tracking, and the publication of ATC. The session also outlined the roles and implementation strategy, emphasising the responsibilities of Transmission System Operators (TSOs), the role of central coordinator, and the steps required to implement NTC and ATC in ASEAN. The presentation was followed by a PowerWorld simulation exercise, which encouraged active discussion between participants and the speaker, allowing them to exchange insights on practical challenges and share experiences from their own systems. 

Photo 6. Closing remarks by Nadhilah Shani, Manager of Power Generation and Interconnection at the ASEAN Centre for Energy (ACE). 

Nadhilah Shani, Manager of Power Generation and Interconnection at the ASEAN Centre for Energy (ACE), concluded the workshop by highlighting the key takeaways from the two-day session. ATC was underlined as more than just a technical parameter, but also a bridge between secure operations and market opportunities. The conclusion also emphasised the need for harmonised approaches across ASEAN to unlock the potential of future multilateral power trade, while noting that continuous capacity building, knowledge sharing, and stronger collaboration between utilities and regulators will be key to strengthening regional preparedness. 

The two-day workshop highlighted the value of exchanging perspectives and experiences among ASEAN Member States to strengthen the region’s technical readiness in implementing ATC. Going forward, ACE will continue to work closely with AMS and partners to foster collaboration, build capacity, and support the development of a more interconnected power system that can accelerate ASEAN’s clean energy transition. 

(MA/FI/ADW)