Achieving a nearly zero energy district through integration of renewable energy: a case study in Valladolid (Spain)

Recently the EU established the new obligations of the member states towards 2030, which are the reduction of CO2 emissions in 40% with regards to the values in 1990, the integration of 32% of renewable energy production, the improvement of energy efficiency in 32.5% and the establishment of 15% of electric interconnection among member states. Beyond 2030, the EU establishes also as global target the decarbonisation of the economy by 2050. While for new buildings the principles to achieve nearly zero or very efficient buildings are well established and technically and economically viable, these principles are less clear in large scale renovations of existing buildings. It is precisely in renovation where the focus should be to reach climate neutrality in the coming 30 years due to the high amount of existing building stock in Europe and the potential that consequently these urban areas offer. The strategies to achieve nearly zero retrofitted buildings have to balance technical solutions, economic viability and integration of renewable sources. Also, the issue of scale becomes essential, where districts can be considered as a system of complex interconnections, interactions, relationships and flows that offer greater flexibility to integrate certain Energy Conservation Measures (ECMs) or to implement specific business models. Therefore a comprehensive approach is essential for effective decision-making with regards to energy efficiency improvement. Thus, approaches for a comprehensive and integrated renovation of districts are needed to unlock the full potential existing on retrofitting the building stock. This paper builds on this element and presents the energy retrofitting of a residential neighborhood in Spain under the EU funded project REMOURBAN that has followed an integrated approach to design the appropriate combination of ECMs leading to 40% of energy consumption reduction and 85% of CO2 emissions avoided to the atmosphere.