Variability Sources in Environmental Impacts of Electrical Building Energy Systems

Energy efficiency and renewable energy have been a main goal of new buildings. To evaluate their overall sustainability, environmental impacts need to be assessed. However, as a new and quickly evolving technology, many variables need to be assumed or estimated. Accordingly, this work aims to evaluate the effects of uncertainty of inputs in the environmental evaluation of energy systems of buildings. Special focus should be given to circular economy principles as an impact reduction strategy of electrical energy system components. A German house is selected as a base case. Input distributions in literature are identified and a simplified Life Cycle Assessment is performed in a Monte Carlo simulation. Results indicate that heating demand is the main contributor to impacts. Component circular economy variables show photovoltaic module life (−38%), resource efficiency [kg/w] (34%) and resource efficiency technological improvement [(kg/w)/(kg/w)] (40%) as the most correlated factors to impacts. Final impact interquartile range lies between 93% and 108% of the median. Extreme cases can achieve up to 75% or 140%. The effects of slight deviating from mean values does not significatively change final impacts. Recognizing this, the most influential components are photovoltaic modules.