Climate-neutral buildings – Impact of existing definitions on building design

Abstract: Climate change poses one of the most substantial threats to humanity today global greenhouse gas emissions are not reduced drastically in the near future, it can lead to severe consequences worldwide. To address this issue, global and national goals have been developed which aim to foster climate-neutral societies and industries. Since emissions from the construction industry are shown to have a significant climate impact, it is crucial to assess their impact and take necessary initiatives. In this regard, several definitions of climate neutrality for the construction industry have been developed in the past few decades to minimize the impact of building construction on the environment and climate. Despite this, there appears to be disagreement regarding what should be included in such a definition. This thesis aimed to investigate different definitions of climate neutrality in the construction sector, focusing on 'climate-neutral buildings' and how these impact building design. Three certifications were investigated: White Architects, NollCO₂ from the Swedish Green Building Council, and Zero Emission Buildings (ZEB) from the Norwegian Research Institute. A methodology for assessing the certifications under consideration was developed following a literature review analysis that provides a relevant context for the study. Total carbon emissions were calculated based on the system boundaries of energy and LCA for each of the definitions. Furthermore, climate neutrality was ascertained with the climate compensation measures considered from each definition. Attention was paid to various climate offset measures to balance the climate impact obtained from each definition. The results from the study indicate that the building managed to reach climate neutrality according to White, NollCO2, and the lowest ambition level from ZEB definition requirements. Despite the same geometry in all the definitions, the same building design couldn't be certified as climate-neutral without incorporating energy measures like heat pump integration. The study also showed that each definition has divided opinions regarding the choice of system boundaries and approaches to achieving climate neutrality. All certifications agreed to include A1-A5 modules in the climate impact calculations except for the lowest ambition level of ZEB. Moreover, all the definitions provided consensus to account for the emission of operational energy. The contrast here was seen primarily in terms of what type of energy was being accounted for. Various climate measures were considered to balance the climate impact, which essentially comprised of the following: production and export of renewable energy, purchased climate compensation, and storage value of biogenic carbon in wood. In addition, while PV systems from all three certifications are likely to have a certain impact, particularly in NollCO2 and ZEB, it is evident that PV emissions outweigh other emissions in the A1-A3 module, unlike the White certification. Furthermore, different PV system sizes were incorporated in all the climate-neutral definitions linked to carbon emission compensations which inferred a difference in cost associated with climate neutrality.