Energy produced from the burning of fossil fuels, resulting in greenhouse gas emissions (GHG), is recognised as one of the primary causes of global warming. Energy, viewed as tonnes of GHG emissions, fundamentally alters the way in which we conceptualise buildings and cities. It demands a shift from quest for systemic energy efficiency to questions of how energy is produced, transmitted, utilised and reutilised. It extends beyond management of operational energy on-site to include energy consumed off-site; for instance, the sourcing of products, the assembly and disassembly of materials and building systems. This module paints the broad picture of energy in its various forms and guises, as it pertains to global warming, in the context of drawing-board decisions on buildings and neighbourhoods.