Towards nearly zero-energy buildings in Mediterranean countries: Energy Performance of Buildings Directive evolution and the energy rehabilitation challenge in the Spanish residential sector

In Spain, the regulation of energy savings in buildings has evolved in parallel with the Energy Performance of Buildings Directive (EPBD). With the upcoming Basic Document on Energy Saving of the Technical Building Code (CTE-DB-HE 2018), nearly zero-energy buildings (NZEBs) are addressed for the first time, including both new buildings and renovated buildings. The goal of the present work is to present the innovations of the forthcoming modifications introduced by the implementation of the EPBD 2010 in Spain, highlighting the energy rehabilitation possibilities offered, with a goal of achieving the classification of all buildings as NZEBs by 2020. To illustrate these modifications, a complete case study is analyzed, in which the improvements introduced with respect to the previous regulation are checked against the new renewable energy contribution requirements for the production of domestic hot water, energy demand limits and energy consumption limits of the upcoming CTE-DB-HE 2018. In this way, we clarify how the energy consumption of the residential building stock is expected to be reduced and how policies that favor building energy rehabilitation can be encouraged to achieve the European goals for 2020 and 2030.