From Zero Energy to Zero Power Buildings: A new framework to define high-energy performance and carbon-neutral buildings

The definition of Zero Energy Building (ZEB) has often been controversial both in regulation and research. This work explores a new evaluation framework introducing the Zero Power Building (ZPB) concept, a novel method that studies the relationship of buildings to the physical boundary, weighting system and analysis timeframe, approaching performance assessment at reduced time intervals. The methodology proposed in this paper showcases how the limitations of the ZEB can be overcome by adopting the ZPB concept on a reference commercial building. The case study was analysed under two different scenarios, with and without an electric storage system. The application of the ZPB concept on an hourly basis poses a challenge to the case study performance, considering both final energy use and CO2 emissions. Specifically, the building commonly accepted as a ZEB turns as a ZPB for only 54.76% of annual hours and as carbon-neutral building for 55.58% of annual hours. The paper presents an innovative methodology that aims to assist in the design and operation of future buildings, as well as provide guidance for policymakers and regulators. The findings emphasize the significance of using dynamic assessment strategies to accurately evaluate the buildings performances and enable meaningful comparisons in various contexts.