Profitability comparison of active and passive energy efficiency improvements in public buildings

Abstract

Buildings and construction are responsible for about 40% of the energy and process-related CO2 emissions worldwide. At present, the renewal rate of building stock is relatively low, for example in Finland, which is the case under study in this work, it is 1.5% per year. With respect to the target of a carbon neutral world by 2050, the effect on emissions of existing building stock must be considered. In this paper, we present the results of analysis of energy efficiency improvement investment in 12 city-owned buildings in two Finnish cities. Using measured heat and electrical energy consumption data, a model was developed for analyzing the impact of active and passive energy efficiency improvement investment options per building. The examined active technologies were heat pumps, solar photovoltaic panels, and heat recovery in ventilation system, and the passive improvement compared was structural improvements in the building envelope. The results show that investments in energy efficiency improvements can reduce the yearly energy-related operating costs of the buildings by 35% on average. The study further finds that usually investment in active energy efficiency improvements provides a bigger return on investment than passive improvements. The profitability of examined measures makes Public–Private Partnership a feasible way to provide funding for renovation of public buildings. Graphical abstract [Figure not available: see fulltext.].