A 3D City Model as User Interface Connected to an Energy Model

Back in 2007 the municipality of Frederikshavn in Northern Jutland in Denmark decided to use only 100% renewable energy for electricity, heat and transport by the year of 2015. Frederikshavn, the largest city in the municipality, was naturally chosen as case city. To be able to verify whether the green energy balance is possible to achieve, it was necessary to create energy scenarios for the whole city and also give the possibility to alter the current energy production and consumption. At the same time the city decided to involve as many people living in the city as possible, making it a project for the citizens of Frederikshavn. One result of this decision was an interactive Web application developed at Aalborg University. The application uses a 3D city model of the city of Frederikshavn as interface and gives the possibility to alter inputs for the energy consumption and energy production of the city using sliders and buttons as part of the interface. While the 3D model gives an immediate visual result, a connection to an underlying numerical energy model developed in earlier years at the University delivers a quite precise calculation on all vital data involved in the overall calculation of renewable energy within a closed energy system. This chapter describes the underlying theories and methods for creating such a system and presents the system, which can be understood as a case story among many.