This report was prepared by the Working Group for Distributed Energy System (DES) in ASEAN under the Energy Project of the Economic Research Institute for ASEAN and East Asia (ERIA). . The findings, interpretations, and conclusions expressed herein do not necessarily reflect the views and policies of the Economic Research Institute for ASEAN and East Asia, its Governing Board, Academic Advisory Council, or the institutions and governments they represent. The findings. . Led by solar PV, renewables are set to enter a period of rapid expansion, supplying over 50-90% of Southeast Asia's electricity by 2050. Flexibility sources need to keep up with the growth of VRE The framework allows policy makers to identify VRE integration measures that need to be prioritised at. . nstraints, is facing unique challenges in the energy transition. The combination of the shift to renewable energy and the lack of grid stability in several Southeast Asian nations indicates the need for storage technologies, a need which is starting to be recognised at governmental level. This. . Southeast Asia's power demand is growing fast, while grid reliability and tariffs vary widely across countries and islands. For commercial sites, adding energy storage systems (ESS) to solar PV isn't just a “green” upgrade—it's a practical way to stabilize operations, shave peak demand, back up. . Energy storage systems (ESS) are integral to balancing renewable energy fluctuations, improving grid resilience, and reducing greenhouse gas emissions. This paper examines the role of international organisations, including the United Nations, International Energy Agency (IEA), and International. . The energy transition in Southeast Asia is gathering momentum, but the road ahead remains complex. For countries like Vietnam, Indonesia, the Philippines, Cambodia, and Thailand, the challenge is not only decarbonizing electricity supply but doing so in a way that keeps pace with demand growth. .