Addressing the apparent tensions between modernity and sustainability in Southeast Asia, this book offers novel insights into the global challenge of moving towards a low carbon energy system. With an original and accessible take on social theory related to energy transitions, modernity and sustainability, Mattijs Smits argues for a reinvigorated geography of energy. He also challenges universalistic and linear assumptions about energy transitions and makes the case for ’energy trajectories’, stressing embeddedness, contingency and connections between scales. Contemporary and historical empirical examples from Southeast Asia, primarily Thailand and Laos, are drawn upon to show the importance of scale at regional, national, local and household levels. The transitions in the national power sectors here have been intimately related to discourses of modernity and state formation since the colonial era. More recently, plans for international cooperation and discourses of regional power trade have taken centre stage. Local energy trajectories are understood to be part of these transitions, but also as embedded in local social, political and spatial relations. Examining how energy practices go hand-in-hand with the dissemination of different technologies, this work shows the complexities of achieving sustainability in the context of rapidly changing energy modernities in Southeast Asia.