Building energy models and assessment systems at the district and city scales: A review

Understanding how and why cities and the urban fabric contribute to energy consumption and greenhouse gas (GHG) emissions is a crucial issue regarding climate change and resource scarcity. A critical review is presented of the calculation tools, models, and assessment systems that deal with energy consumption and GHG emissions from buildings at the district and city scales. The review encompasses international assessment systems and technical models developed in Japan, North America and Europe. The relationships and connections between policy and research within these systems are examined. Chronic systemic failures are highlighted that should be addressed rapidly in the research agenda. The negative impacts are considered in terms of the operational potential due to the use of rough aggregation methods. The analysis emphasizes the need for more systemic, multi-scale and transverse approaches to deal with the intrinsic complexity of the urban fabric. Four intervention points for urban efficiency are proposed: urban morphology, buildings' efficiency, systems' efficiency and individual behaviours. Harnessing all of these would improve the potential of models and assessment systems. Combining these urban efficiencies would have a multiplier effect in terms of actual outcomes in reducing energy consumption.