Factors influencing the life-cycle GHG emissions of Brazilian office buildings

Kamila Krych,Edgar G Hertwich,Niko Heeren

doi:10.5334/bc.136

Abstract

Effective mitigation of greenhouse gas (GHG) emissions in the buildings sector requires a full understanding of the factors influencing emissions over the life-cycle of buildings, particularly in places where large additions to the building stock are expected. Currently, little is known about what affects the GHG emissions of buildings located in warmer climates, a typical situation for many emerging economies. This paper presents a study of emissions from Brazilian office buildings using building archetypes. A sensitivity analysis explores possible parameter ranges, various contributions to life-cycle impacts and their key drivers. For each of the 1000 building variations in the sample, the emissions were calculated using a life-cycle assessment. Multivariate regression analysis enabled the study of the results’ sensitivity to 10 parameters, influencing building operation, design and others. The emissions ranged from 20 to 106 kg CO2-eq/m2 gross floor area and year. Electricity mix, climate and cooling efficiency were the most impactful parameters, but building component service time was also significant. Policy relevance Emerging economies are expected to rapidly increase their building stock and energy use, particularly for cooling in the coming decades. The findings show the key factors influencing the GHG emissions of office buildings in warm climates, typical for many emerging economies, such as Brazil. For effective mitigation, priority should be placed on reducing the carbon intensity of electricity and encouraging highly efficient heating, ventilation and air-conditioning systems. Policymakers may want to offer incentives for office buildings with a combination of natural ventilation and mechanical cooling, because they were less emission-intensive in every investigated city. The benefits are the biggest for buildings in which a high proportion of windows can be opened for natural ventilation.

Highlights

Buildings and CitiesOffice buildings are among the most important types of commercial buildings
Numerous studies have been conducted on life-cycle energy use (Cole & Kernan 1996; Dimoudi & Tompa 2008; Junnila et al 2006; Kofoworola & Gheewala 2009; Wang et al 2018; Yohanis & Norton 2002) and greenhouse gas (GHG) emissions (Airaksinen & Matilainen 2011; Asdrubali et al 2013; Chau et al 2012; Dimoudi & Tompa 2008; Eberhardt et al 2019; Frischknecht et al 2019; Junnila et al 2006; Kofoworola & Gheewala 2008; Kumanayake et al 2018; Lessard et al 2018; Suzuki & Oka 1998; Wallhagen et al 2011; Yan et al 2010; Ylmén et al 2019) of office buildings, with some focused on material-related impacts (Chau et al 2012; Dimoudi & Tompa 2008; Eberhardt et al 2019; Yan et al 2010)
The archetype modelling approach was used to estimate life-cycle GHG emissions of office buildings located in Brazil

Summary

Introduction

Buildings and CitiesOffice buildings are among the most important types of commercial buildings. The increasing need for office floorspace is generally coupled with service sector growth (Deetman et al 2020), observed in most important emerging economies (UN 2021). This building type is responsible for a significant share of building-related greenhouse gas (GHG) emissions. The available estimates of life-cycle emissions of office buildings vary significantly, as shown in Table S1 in the supplemental data online

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Results

Conclusion