Life Cycle Assessment of a Fiberglass House in Iceland
Buildings are a major contributor to greenhouse gas (GHG) emissions, accounting for around 38% of global emissions. In previous life cycle assessment (LCA) studies, the use phase was associated with the highest lifetime emissions from buildings, but more recent studies show the relative importance of the pre-use phase. The pre-use phase becomes even more significant as the carbon intensity of energy production decreases, reducing use phase emissions proportionally, and the energy efficiency of buildings increases, increasing the proportion of pre-use phase emissions. This is largely due to the use of traditional building materials, such as concrete and steel, which have some of the highest embodied emissions of conventional building materials. Many LCA studies focus only on embodied GHG emissions but studies show that it is also relevant to look beyond GHG emissions. For more comprehensive reporting of environmental impacts, it is necessary to develop a baseline for comparison which this study, among others, contributes to. In this thesis, the case study assesses the environmental impacts from a residential house in Iceland utilizing fiberglass and stone wool panels as the main building materials. The study is a process LCA, modelled in the OpenLCA software using the Ecoinvent 3.7 inventory database. The ReCiPe 2016 impact assessment method is used to calculate environmental impacts for 18 midpoint categories and 3 endpoint categories. A hotspot analysis shows the relative contribution from each building material to the midpoint impact categories. The use phase GHG emissions are modelled in Iceland, Poland, and Finland using the same LCA method. The results of this study determine the embodied GHG emissions of the case house to be 324 kg CO2eq/m2 in Iceland. The hotspot analysis identifies fiberglass as the main contributing material to many impact categories, followed by steel and copper. The frame/walls and foundation are also identified as an environmental hotspot, largely due to the use of fiberglass and steel. Additionally, the use phase comparison shows the pre-use phase makes up most of the impacts in Iceland and Finland. In Iceland specifically, the use phase emissions are minimal compared to the pre-use phase due to their reliance on renewable energy. This highlights the importance of assessing the pre-use phase in lifetime GHG emissions. With the increasing threat of climate change, policy and technological changes are urgently needed to reduce environmental impacts from the building sector. More research on the environmental impacts from alternative building options, addressed in this study, will be necessary to inform such changes.
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