Climate Impact from Operational Energy Use in Facilities & Households

Detta är en Master-uppsats från KTH/Hållbar utveckling, miljövetenskap och teknik

Sammanfattning: In 2017, the Swedish Parliament voted for a climate aim which says Sweden should achieve zero net emissions of greenhouse gases in 2045. The building and construction sector is one of the sectors that needs to reduce it’s climate impact. As of 2016, 12.8 million tons of CO2-equivalents was estimated emitted from the sector, which represented about 21 percent oftotal amounts of GHG-gases emitted from Sweden in that year. Several studies has shown that the operational energy use in the life cycle of buildings is source to the majority of the emissions. This thesis was written in collaboration with Skanska Sweden, a Swedish construction company. Currently, there is no available value for the CO2-emissions emitted per m2 from the operational energy use in facilities and households at Skanska Sweden. The aim of this report is therefore to estimate the CO2-emissions emitted per m2 from various building types.This has been achieved through data investigations of what data is available and missing. Furthermore, methodologies have been investigated as well as energy sources for various buildings. Then the emissions were calculated as CO2-eq/m2 per building type. A sensitivity scenario was additionally performed by calcuating climate impact from different electric grids (Swedish, Nordic and European). Finally, a future energy scenario was investigated for2050 to estimate future climate impact from the operational energy use in various building types. The energy data was based on two different databases, Base and Follow Up, whereas Base presented estimated energy interval values. Follow Up presented estimated and verified values. In the data collection, a categorisation was made depending on the various building types Skanska Sweden produces. The 7 categories was Houses, Multi-dwelling buildings,Offices, Care centers, Schools, Pre-schools and Other. The findings were that in all categories but two (schools and offices), the operational energy use is higher when the values are verified, rather than estimated. Recommendations are therefore to increase the amount of available verified values, however, at the same time the amount of estimated values need to increase as well as many categories had a deficient amount of available data, this to increase the reliability of the results. The difference in calculated climate impact is relatively large between categories, depending on energy sources for heating and hot tap water. For instance is the climate impact lowest for Houses when the majority of the energy comes from electricity. At the same time, the climate impact from the category Other is highest, which is because the energy use is high, but additionally because the majority of the energy comes from district heating. Overall, this energy source has higher climate impact than when the electricity is used. Nevertheless, it should be observed that the difference in categories is overall huge, depending on the chosen electricity grid. Future emissions (2050) will be significantly lower than today, especially when the European grid and the EU reference scenario is chosen, but will be dependent on electricity prices additionally. However, if the Swedish climate aim of climate neutrality will be achieved, the climate impact from the operational energy will be minimal in 2050. An important aspect in environmental evaluations of energy is methodological choice. In this project, the attributional perspective has been chosen, however, many studies imply the importance of margin energy, which the attributional perspective does not include.Furthermore, the attributional may present a lower climate impact than when other methodologies are chosen. It is therefore important to be aware of the methodology used and recommendations for future studies would be to investigate the methods more thouroughly.

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