ACKNOWLEDGEMENT Thesuccessful completion of theASEAN Interconnection Masterplan Study (AIMS) III Phase 3–MinimumRequirements for Multilateral Power Trade in ASEANis attributed to the collaborative efforts of theASEANCentre for Energy (ACE)and partner organisations, as well as individuals whose combined expertise, steadfastsupport, and dedicated contributions significantly enhanced the quality and depth of the work.This publicationwas made possible with the generous co-funding from theEU-ASEAN Sustainable Connectivity Package(SCOPE) Energy, theSoutheast Asia Energy Transition Partnership (ETP), andDeutsche Gesellschaft fürInternationale Zusammenarbeit(GIZ)via the project Clean, Affordable, and Secure Energy for Southeast Asia(CASE), which is funded by theFederal Ministry for the Environment, Climate Action, Nature Conservationand Nuclear Safety (BMUKN) through the International Climate Initiative (IKI). This joint effort supports theimplementation ofAPAEC Programme Area No. 1 on the ASEAN Power Grid (APG). Authors:This publication was developed byACE. The lead authors areNadhilah Shani, Akbar Dwi Wahyono,and Marcel Nicky Arianto(ACE). An earlier draft of the study was prepared byRicardo PLC(consulting teammobilised by the Southeast Asia Energy Transition Partnership, a programme of the United Nations Office forProject Services,ETP-UNOPS), namelyRomeo Pacudan, Jonathan Hedgecock, Graeme Chown, and Hans-Arild Bredesen. Guidance and Supervision:Special recognition is extended toDato’ Ir. Ts. Razib Dawood, Executive Director ofACE, andBeni Suryadi, Senior Manager of the ASEAN Plan of Action for Energy Cooperation (APAEC) Department,ACE, for their instrumental role in providing overall guidance and supervision throughout the development of thispublication. Contributing ASEAN Member States:Recognition is extended to theASEAN Member States (AMS), whoseexpertise and commitment played a pivotal role in shaping the findings of the report. We are particularly gratefulto theAIMS III Phase 3 Working Groups—including representatives from the Heads of ASEAN PowerUtilities/Authorities (HAPUA), theASEAN Energy Regulators Network (AERN), and theASEAN Power GridConsultative Committee (APGCC)of each ASEAN Member State—for providing constructive inputs throughdiscussion papers and workshops conducted as part of the strategy to accelerate the ASEAN Power Grid (APG)and expand multilateral power trading. Supporting Organisations:This study is an output of theASEAN Power Grid Advancement Programme (APG-AP), an initiativeofACE,ETP-UNOPS,GIZ, and theUnited Nations Economic and Social Commission for Asiaand the Pacific (ESCAP). Sincere appreciation is extended to these organisations for their collaborative supportin facilitating the research and publication process. Reviewers:The delivery of the study was strengthened through technical review and coordination provided byDimas FauziandAdritha Subbiah(ETP-UNOPS),Sascha OppowaandMaximilian Heil(GIZ), andMatthewDavid Wittenstein, KieranGeorge Clarke, and Yejin Ha(ESCAP). The study was also benefitted from thefeedback of experts from the AIMS III Phase 3 Technical Reviewer Group, namelyRena Kuwahata, PeerapatVithayarischareon, Yinlun Teng, and Natalie Kauf(International Energy Agency or “IEA”) andGrayson Heffner,Hyunjung Lee, and Amelia Esteban(Asian Development Bank or “ADB”). Design and Layout:Acknowledgment is given toFadhiel Handira IshaqandMuhammad Bayu Pradana Effendyfor their creative contributions to the design and layout of this publication. Communications Team:Special recognition goes toFirdaus Fadhlullah DesignerindyandAmara Zahra Djamilfor their efforts in preparing the communications strategy and supporting the final stages of preparing thispublication for distribution. This collaborative effort reflects the dedication of a diverse group of organisations and individuals, and their valuable contributions are trulyappreciated. CONTENTS 1EXECUTIVE SUMMARY11.1TECHNICAL PROPOSALS21.2PROPOSALS FOR MULTILATERAL POWER TRADE71.3INSTITUTIONAL PROPOSALS122INTRODUCTION173TECHNICAL PROPOSALS193.1INTRODUCTION203.2REVIEW OF ASEAN INTERCONNECTION STATUS203.2.1Summary of Existing and Planned Interconnector Status and Progress203.2.2Review of Existing Country Power Development Plans (PDPs)213.3BEST PRACTICE AND CONSIDERATION IN SELECTING TYPE OF INTERCONNECTION TECHNOLOGY INAPG (HVDC/HVAC)223.3.1Introduction223.3.2HVDC Inverter Technologies233.3.3Typical Use of HVDC243.3.4Costs of HVDC vs HVAC253.3.5HVDC Power Flow Capability273.3.6Frequency Control using HVDC293.3.7HVDC Primary Frequency Control in the Gulf Region,303.3.8HVDC Primary Frequency Control in the European Region313.3.9Choosing between Grid Forming and Frequency Following Inverters for HVDC343.3.10HVDC Grid Forming Inverter Island Information353.3.11Comparing HVAC option and HVDC Grid Forming Inverters373.3.12HVDC Supply Chain Constraints373.3.13Summary373.4TRANSMISSION TARIFF MECHANISMS AND WHEELING CHARGES383.4.1Agreemen