Taking the step towards Net Zero Energy Buildings - How will that affect the energy use from a life cycle perspective?

Abstract

An important measure for climate change mitigation is reduction of energy use in buildings worldwide. There are today a growing number of buildings for which the design principle has been to achieve a Zero Energy Building (ZEB) or Net Zero Energy Building (Net ZEB). It is today generally assumed, when the energy use of a building is discussed from a LifeCycle perspective, that energy use in the operational phase of buildings accounts for 70-90% of energy used during its life cycle. However, a natural consequence is that for Net ZEBs the relative share of energy use related to building operation will decrease. Some might argue that the energy savings achieved related to building operation of a Net ZEB is lower compared to the increased energy use for production, maintenance and demolition. This study analyzes the change of embodied energy compared to the decrease of the energy use related to building operation; by literature review and detailed analysis of eleven case studies, taking the step from a low energy building to a Net ZEB.