Towards Nearly Zero-Energy Buildings in Cold Rural Mediterranean Zones: The Case of La Rioja (Spain)

Abstract

The European Union aims for its existing building stock to be highly energy-efficient and decarbonized by 2050 through long-term renovation strategies so that all residential buildings are nearly zero-energy buildings. The objective of this work is to determine the optimal energy renovation solution for rural residential buildings located in cold climate zones of Spain to achieve nearly zero-energy buildings. For this purpose, the energy, environmental and economic impacts of 48 energy renovation proposals in three different climate zones are assessed, taking La Rioja as a case study. Considering these impacts, the optimal solution is a solution that improves the thermal envelope, applying the life cycle cost analysis, and that uses renewable energy sources to meet thermal needs and a portion of the electrical energy needs. Under the optimal solution, overall savings of up to EUR 2.4 can be achieved for each euro invested, resulting in reductions in non-renewable primary energy consumption by up to 97%, total primary energy consumption by up to 81% and CO2 emissions by up to 97%. The methodology followed and the results obtained can serve as a guide for establishing energy renovation policies in other cold rural Mediterranean zones.