Life Cycle Assessment of a Nearly Zero-Energy Neighborhood in Belgium
Life Cycle Analysis (LCA) is the most appropriate method to quantify scientifically the environmental and health impacts of buildings. The purpose of this research is to determine, at the neighborhood scale, the most important sources of buildings’ environmental impacts, based on twelve different environmental impacts including the health impact. This paper compares the impacts on the environment generated by an existing energy efficient neighbourhood, where all the buildings should be passive, and its transformation into a zero-energy district thanks to the addition of numerous photovoltaic panels on the roofs of the buildings. For that, we used the combination of three simulation tools — ALCYONE, COMFIE-PLEIADES and nova-EQUER for studying the Life Cycle Assessment (LCA) of buildings and networks (roads, parking, etc). An eco-neighbourhood, located near the University of Liege in Belgium, has been selected as the case study. The buildings heating modelled by the dynamic thermal simulation has an average heating load of 15.4 kWh/m².year.Photovoltaic panels on all the roofs of the buildings allow achieving a nearly zero-energy neighbourhood and can mitigate up to 25% of greenhouse gas emissions of the passive neighborhood and reduce 5% of its health impacts. However, the photovoltaic panels have a mixed environmental record for other indicators, with a majority of the environmental impacts being improved compared to the passive neighborhood, but four of the twelve environmental impacts studied being increased.We also notice the strong predominance of the occupation phase on the life-cycle environmental impacts of this nearly zero-energy neighborhood. The use phase concentrates more than 70% of the greenhouse gas production and of the cumulative total energy demand of the neighborhood calculated during 80 years. Moreover, the results show a very strong participation of the mobility component and the household waste management component, in the LCA, at the neighbourhood level. The cumulative energy demand from inhabitants’ mobility and waste management during the use phase was 60% of the total cumulative energy demand of the neighbourhood, over its entire life cycle. The results show also that an improved mobility management allows reducing all the environmental impacts of the neighborhood and may reduce its health impacts up to 32%.
Keywords - Life cycle assessment, urban scale, zero-energy neighborhood, health impact, environmental impacts.