Roof mounted PV system : Navigating implementation prerequisites for property with certain requirements

Abstract: The purpose of this study is to evaluate the potential of a PV installation for the Swedish real estate company Specialfastigheter. The main objective with such an implementation is that the state-owned company aims to decrease their carbon footprint. Consequently, the study takes into consideration both technical and economic as well as environmental aspects. Furthermore, Specialfastigheter’s operation includes administering special purpose properties, leading to certain requirements concerning safety and secrecy. The PV implementation is to be made on the roof of one of Specialfastigheter’s properties and different installation and mounting solutions are evaluated. The results are presented in an optimized base case, taking into consideration the amount of electricity produced as well as investment cost and payback period. The installation’s environmental impact in terms of carbon dioxide equivalents is then reviewed. A sensitivity analysis of the results is performed in order to study how any changes in prerequisites will affect the project’s profitability. The results show that with a required discount rate of 5.6%, the payback time will be 37 years and thus exceeding the life span of the system. Nevertheless, the investment will be profitable if the discount rate is set to 4.6% or if the investment cost is lowered by 10%, for instance by investment aid. The percentage decrease in greenhouse gas emissions is not remarkable; however, in absolute numbers the results imply a substantial reduction of the property’s carbon footprint. The low percentage gains could instead be explained by the vast electricity consumption for the property.