Modelling energy demand in the Norwegian building stock

• Main Author: Sartori, Igor
• Format: Doctoral Thesis
• Language: English
• Published: Norges teknisk-naturvitenskapelige universitet, Institutt for byggekunst, historie og teknologi 2008
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2332; http://nbn-resolving.de/urn:isbn:978-82-471-1123-9

Energy demand in the building stock in Norway represents about 40% of the final energy consumption, of which 22% goes to the residential sector and 18% to the service sector. In Norway there is a strong dependency on electricity for heating purposes, with electricity covering about 80% of the energy demand in buildings. The building sector can play an important role in the achievement of a more sustainable energy system. The work performed in the articles presented in this thesis investigates various aspects related to the energy demand in the building sector, both in singular cases and in the stock as a whole. The work performed in the first part of this thesis on development and survey of case studies provided background knowledge that was then used in the second part, on modelling the entire stock. In the first part, a literature survey of case studies showed that, in a life cycle perspective, the energy used in the operating phase of buildings is the single most important factor. Design of low-energy buildings is then beneficial and should be pursued, even though it implies a somewhat higher embodied energy. A case study was performed on a school building. First, a methodology using a Monte Carlo method in the calibration process was explored. Then, the calibrated model of the school was used to investigate measures for the achievement of high energy efficiency standard through renovation work. In the second part, a model was developed to study the energy demand in a scenario analysis. The results showed the robustness of policies that included conservation measures against the conflicting effects of the other policies. Adopting conservation measures on a large scale showed the potential to reduce both electricity and total energy demand from present day levels while the building stock keeps growing. The results also highlighted the inertia to change of the building stock, due to low activity levels compared to the stock size. It also became clear that a deeper understanding of the stock dynamics was needed as a precondition for addressing energy demand in a more consistent way. A methodology was developed for assessing in a coherent way both the stock and the building activities, i.e. construction, renovation and demolition. This methodology applies only to the residential stock. The analysis showed that in the coming decades renovation is likely to overtake construction as the major activity in the Norwegian residential stock. Finally, the two models, the energy model and the activity model, were merged to perform an integrated analysis of the energy demand at a regional level. The result showed how considering the stock dynamics have a great impact in determining the effectiveness of a policy.