Net zero emission buildings: next generation of benchmarks and calculation rules

Abstract

The definition of ambitious life cycle-based benchmarks and target values to limit the GHG emissions of buildings is seen as one of the most important steps in pushing the construction and real estate sector in significantly reducing its contribution to global warming. Especially target values are no longer only developed from a bottom-up perspective. There is now an interest by governments and sustainability assessment system providers in supplementing bottom-up approaches with science-based top-down approaches as part of their responsibility to respect planetary boundaries. The creation of GHG emission budgets in combination with target values, as well as the introduction of strict enough legal binding requirements already today is critical for achieving a climate-neutral building stock. Achieving these tasks requires tackling still open methodological issues. Following the work of IEA EBC Annex 72 and current developments in Germany, the paper presents main questions, key steps, modelling aspects that can cause variation and uncertainties, as well as clarifies key terms and definitions. It is highlighted that although a net zero emission requirement is a universal benchmark, information on system boundaries and calculation rules are still necessary to provide evidence of its fulfilment.

Monitoring and reporting of buildings’ greenhouse gas emissions: implementation in the Austrian building submission procedure

“…Bottom-up approaches are based, for example, on statistical evaluations of building samples or on analyses of building archetypes [33].…”

A comparative assessment of the development of GHG emission criteria and benchmark values for buildings in Norway

“…To meet national and international climate goals, various GHG emission criteria and benchmark values for buildings are being developed [3]. However, there is a distinct lack of harmonisation in methods and approaches making it difficult to compare construction projects or implement and apply benchmarking at a national or international level [4,5]. Norway is no exception.…”

“…Previous studies have compared environmental sustainability assessment schemes for buildings, whereby GHG emissions is often identified as an important criteria [15][16][17][18][19][20][21]. More recently, the IEA EBC Annex 72 has investigated net zero emission buildings and the next generation of benchmark and calculation rules and found that there are large differences in GHG emission targets for buildings [4]. Another study has investigated indicative baseline and decarbonisation pathways for embodied life cycle GHG emissions of buildings across Europe and found that whole life cycle (WLC) embodied carbon emissions range from 400 -800 kgCO 2 e/m 2 (6.6 -13.3 kgCO 2 e/m 2 /yr), averaging at 550 kgCO 2 e/m 2 (9.2 kgCO 2 e/m 2 /yr) for residential buildings [5].…”