Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

Martin Röck, Marcella Ruschi Mendes Saade, Maria Balouktsi, Freja Nygaard Rasmussen, Harpa Birgisdottir, Rolf Frischknecht, Guillaume Habert, Thomas Lützkendorf, Alexander Passer

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Buildings are major sources of greenhouse gas (GHG) emissions and contributors to the climate crisis. To meet climate-change mitigation needs, one must go beyond operational energy consumption and related GHG emissions of buildings and address their full life cycle. This study investigates the global trends of GHG emissions arising across the life cycle of buildings by systematically compiling and analysing more than 650 life cycle assessment (LCA) case studies. The results, presented for different energy performance classes based on a final sample of 238 cases, show a clear reduction trend in life cycle GHG emissions due to improved operational energy performance. However, the analysis reveals an increase in relative and absolute contributions of so‐called ‘embodied’ GHG emissions, i.e., emissions arising from manufacturing and processing of building materials. While the average share of embodied GHG emissions from buildings following current energy performance regulations is approximately 20–25% of life cycle GHG emissions, this figure escalates to 45–50% for highly energy-efficient buildings and surpasses 90% in extreme cases. Furthermore, this study analyses GHG emissions at time of occurrence, highlighting the ‘carbon spike’ from building production. Relating the results to existing benchmarks for buildings’ GHG emissions in the Swiss SIA energy efficiency path shows that most cases exceed the target of 11.0 kgCO2eq/m2a. Considering global GHG reduction targets, these results emphasize the urgent need to reduce GHG emissions of buildings by optimizing both operational and embodied impacts. The analysis further confirmed a need for improving transparency and comparability of LCA studies.
Original languageEnglish
JournalApplied Energy
Volume258
DOIs
Publication statusPublished - 2020

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Gas emissions
Greenhouse gases
Climate change
greenhouse gas
Life cycle
life cycle
energy
climate change mitigation
energy efficiency
transparency
Transparency
Energy efficiency
manufacturing
Energy utilization
Carbon
carbon

Keywords

    Fields of Expertise

    • Sustainable Systems

    Cite this

    Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation. / Röck, Martin; Saade, Marcella Ruschi Mendes; Balouktsi, Maria; Rasmussen, Freja Nygaard; Birgisdottir, Harpa; Frischknecht, Rolf; Habert, Guillaume; Lützkendorf, Thomas; Passer, Alexander.

    In: Applied Energy, Vol. 258, 2020.

    Research output: Contribution to journalArticleResearchpeer-review

    Röck, M, Saade, MRM, Balouktsi, M, Rasmussen, FN, Birgisdottir, H, Frischknecht, R, Habert, G, Lützkendorf, T & Passer, A 2020, 'Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation' Applied Energy, vol. 258. https://doi.org/10.1016/j.apenergy.2019.114107
    Röck, Martin ; Saade, Marcella Ruschi Mendes ; Balouktsi, Maria ; Rasmussen, Freja Nygaard ; Birgisdottir, Harpa ; Frischknecht, Rolf ; Habert, Guillaume ; Lützkendorf, Thomas ; Passer, Alexander. / Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation. In: Applied Energy. 2020 ; Vol. 258.
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    AU - Saade, Marcella Ruschi Mendes

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    AU - Rasmussen, Freja Nygaard

    AU - Birgisdottir, Harpa

    AU - Frischknecht, Rolf

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    AU - Lützkendorf, Thomas

    AU - Passer, Alexander

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    AB - Buildings are major sources of greenhouse gas (GHG) emissions and contributors to the climate crisis. To meet climate-change mitigation needs, one must go beyond operational energy consumption and related GHG emissions of buildings and address their full life cycle. This study investigates the global trends of GHG emissions arising across the life cycle of buildings by systematically compiling and analysing more than 650 life cycle assessment (LCA) case studies. The results, presented for different energy performance classes based on a final sample of 238 cases, show a clear reduction trend in life cycle GHG emissions due to improved operational energy performance. However, the analysis reveals an increase in relative and absolute contributions of so‐called ‘embodied’ GHG emissions, i.e., emissions arising from manufacturing and processing of building materials. While the average share of embodied GHG emissions from buildings following current energy performance regulations is approximately 20–25% of life cycle GHG emissions, this figure escalates to 45–50% for highly energy-efficient buildings and surpasses 90% in extreme cases. Furthermore, this study analyses GHG emissions at time of occurrence, highlighting the ‘carbon spike’ from building production. Relating the results to existing benchmarks for buildings’ GHG emissions in the Swiss SIA energy efficiency path shows that most cases exceed the target of 11.0 kgCO2eq/m2a. Considering global GHG reduction targets, these results emphasize the urgent need to reduce GHG emissions of buildings by optimizing both operational and embodied impacts. The analysis further confirmed a need for improving transparency and comparability of LCA studies.

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