The use of transient computer simulations (e.g. TRNSYS, Energy Plus) for quantifying energy use of individual buildings is now standard in both research and industry. However, their use has been computationally prohibitive at larger scales, in the context of thousands or millions of buildings within districts and cities. As a result, city scale analyses of the built environment, even when bottom-up, have to neglect or simplify dynamic and transient features of buildings. Yet, it is often that time-varying features (concurrence of peak energy demand) and dynamically interacting components (diurnal heat storage) yield the most economically achievable energy efficien­cies.
We present a new city-scale energy simulation platform that offers a spatially differentiated, hourly analysis of energy consumed by the built environment. The City of Westminster, within central London, was chosen for the first pilot application of this simulation platform due to diversity of building types and high-energy demand. The lecture will highlight the challenges associated with its development, as well as future directions in the area of city-scale energy modeling of the built environment.