Profitability of contracting business cases for shared photovoltaic generation and renovation measures in a residential multi-apartment building
Bernadette Fina, Hans Auer, Werner Friedl
Abstract
This study investigates the profitability of implementing active and passive building retrofitting measures, either individually or combined, within the framework of contracting. Three contracting models are investigated: (i) Photovoltaic (PV) contracting, (ii) renovation contracting, (iii) PV and renovation contracting including a heating system change. Since this study’s practical approach focuses on the client (building owner), an optimisation model is developed that maximises the client’s net present value, subject to a guaranteed pay-off including profit for the contractor. An algorithm allows to exactly quantify the impact of renovation measures on the heat load. The results show that PV system contracting is profitable for contractors and clients, while the profitability of passive retrofitting measures (e.g. building envelope renovation) significantly depends on the additional costs for CO2 emissions as well as on the default heating system. The contracting framework itself decreases the profitability of retrofitting measures since the contractor as a third party awaits to gain profit as well. The significance of said impact depends heavily on the contractor’s expected interest rate. In conclusion, in order to boost the shares of holistically retrofitted buildings (with or without PV integration), increasing costs for CO2 emissions increase attractiveness for both the contractor, and the clients.