The cost overrun of depopulation to improve energy efficiency in buildings: A case study in the Mediterranean Region

The implementation of energy efficiency measures in public buildings is a complex process that hinges on multiple factors. A factor relevant for some European regions is their ongoing depopulation. In these regions, building energy retrofitting presents additional challenges to those in urban areas, such as over-dimensioned public buildings and low occupancy levels. This work analyses these challenges in the province of Teruel (Spain), one of the regions with the highest depopulation levels in Spain. To this end, a methodology has been developed to assess the effect of depopulation on the cost of upgrading public buildings to improve their energy efficiency. The results show that the investment required per inhabitant for building retrofitting is approximately four times as high in depopulated areas as in urban areas. Furthermore, the low occupancy levels of public buildings can triple the payback time of some energy efficiency measures. To overcome these barriers, in addition to specific policies for depopulated areas, energy planning is essential. An adequate action plan, combining the implementation of energy efficiency measures and the integration of renewable energies in buildings, is the most effective tool to improve the sustainability of public buildings circumventing the barriers created by depopulation.