Life Cycle Assessment of an Ambitious Upgrading of an Apartment Building - An Environmental Approach on Upgrading Projects
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A Life Cycle Assessment (LCA) is conducted of an ambitious upgrading of an old apartment building to assess environmental impacts caused by construction materials and related processes. The result of the LCA is compared with a previously performed analysis of the building where the tool Klimagassregnskap.no was used to predict carbon footprint of the building apartment. In order to identify environmental impacts from the ambitious upgrading there was firstly a need to collect all data for materials used in detail, and related construction and transport processes. When the data was gathered and treated, materials were allocated to shell components and processes. Furthermore, the model was linked to the background database ecoinvent version 2.2, and the LCA software Arda was used to process the data. The ReCiPe method, and hierarchist midpoint was utilized for impact assessment. The NORDEL electricity mix was applied for electricity consumption. The results show that total carbon footprint from the Stjernehus upgrading was 439 ton CO2-eq. This includes production of construction materials, transportation to site, energy and diesel used during construction, and end of life treatment of materials, including transport to waste treatment plant (in EPD terminology: A1-A5, B seperate, C1-C4). As the scope of this Life Cycle Assessment was the ambitious upgrading project, the emissions related to energy consumption during user phase was considered separately from emissions embodied in materials. Greenhouse gas emissions from energy use by residents prior to upgrading was 164 ton CO2-eq/year and decreased by 84% to 25 ton CO2-eq/year after the rehabilitation. The study presents two variants of the LCA model. The first in chapter 4 presents the complete inventory list, and the second model has a limited scope to be comparable with results in Klimagassregnskap.no. The comparison in chapter 5 shows that Klimagassregnskap.no calculated a total of 156 ton-CO2 emissions from the upgrading, while the adjusted LCA model found 237 ton CO2-eq. Both the LCA and Klimagassregnskap.no model result in an optimistic approach towards future ambitious upgrading, however the latter tool underestimates emissions from materials. The time before emissions caused by the upgrading project are payed back in energy savings is 3.3 years. Thus this study supports upgrading projects of building apartments in the near future from an environmental perspective. Nevertheless, for such projects to occur and be profitable, there is a need to hold a long-term perspective on economic value and consider societal and environmental values in addition.