Studying the dynamic relationship between energy supply carbon content and building energy demand
Electricity production is achieved by different processes (e.g. nuclear plants, fossil fuels sources, renewables, etc.) with different environmental impacts and capacities of production. To provide the necessary amount of electric energy demand, different sources of different quality are combined together and as a result, the carbon content of the electricity mix varies with time over the day and over the year. Likewise, the usage intensity and the design of a building induce variation of the energy demand at the same time. On the other hand, Switzerland proposes the 2050 energy strategy by fixing new policies to face climate change and decrease the greenhouse gas (GHG) emissions. Therefore, the purpose of this study is to point out the potential of a more dynamic relationship between low carbon content energy supply and building energy demand. To that end, three major steps are necessary and will be presented in this paper. The case study chosen to apply the proposed method is the building of the smart living lab, currently being designed and expected to be built by 2020 in Fribourg Switzerland, as it explicitly aims to achieve the intermediate 2050 goals of the 2000-watt society vision. Firstly, the hourly carbon content of the on-site available energies are evaluated. The Swiss electrical grid is assessed based on the accessible statistical data from the energy producers in Switzerland. The amount of renewable energy harvested by building integrated photovoltaics (BIPV) and its related environmental impact are evaluated with the solar tool PVGIS and the KBOB database. Secondly, the hourly energy demand is assessed thanks to dynamic simulation and to expected dweller usage of the building. Thirdly, the GHG emissions are assessed with the carbon hourly content of the energy supply that is used. The dynamic result is compared to a static approach that would use a yearly average carbon content of the energy supply. Also, the dynamic relationship between low carbon energy supply and building energy demand is analysed. The results of this study point out significant differences between a yearly static and an hourly dynamic GHG emissions assessment. Moreover, the important variation of the carbon content energy supply and of the energy demand demonstrate that a better correlation between these two is a powerful element to increase the performance of a building. In future studies, strategies such as electricity storage, BIPV orientation and tilt, and dweller usage variation should be further investigated.
Record created on 2016-01-07, modified on 2016-08-12