This case study examines the ASEAN Power Grid (APG) through the lens of ASEAN economic regionalism – as a window onto how, and how far, the region can convert political consensus into physical integration. Specifically, it aims to: examine what the APG is, the objectives it serves (ie energy security, the net-zero transition, economic efficiency and universal access) and the institutional architecture that governs it; analyse why the APG matters now, situating it within the region’s climate commitments, geopolitical exposure and the surging electricity demand of its digital economy; evaluate the structural challenges impeding implementation – political and institutional, technical and infrastructural, financial and commercial, and regulatory and market – illustrated through specific interconnection projects; and assess the policy options and watchpoints for ASEAN as it moves from a patchwork of bilateral deals toward a genuinely multilateral grid.