ABSTRACT
As has been discussed in previous chapters, computer models are invaluable tools when trying to assess the performance of an urban energy system. Sometimes these assessments are retrospective, in that the calculations are aimed at determining the impacts of current or past performance. An example might be an assessment of the environmental impacts of observed fuel consumption. More often though, we use models in a predictive sense, in order to make a forecast about the likely performance of a system at some point in the future. However, as Niels Bohr famously said, ‘prediction is very difficult, especially about the future’ and for modellers of any system, the vagaries of prediction are something of a professional hazard. Yet decision-makers in the private and public sector rely upon these tools to make decisions about the future and therefore the predictive accuracy of these tools, or lack thereof, can have serious consequences.
