Reducing CO2 Emissions and Improving Water Resource Circularity by Optimizing Energy Efficiency in Buildings

Climate neutrality by 2050 is a priority objective and reducing greenhouse gas (GHG) emissions, increasing energy efficiency, and improving the circularity processes of resources are the imperatives of regulatory and economic instruments. Starting from the central themes of the mitigation of the causes of climate change and the interdependence represented by the water–energy nexus, this research focuses, through the application of the principles of the circular and green economy, on deep energy zero-emission renovation through the improvement of circularity processes of water resources in their integration with energetic ones on the optimization of their management within urban districts, to measure their capacity to contribute towards reducing energy consumption and CO2 emissions during water use and distribution in buildings. After defining the key strategies and the replicable intervention solutions for the circularity of water resources, the investigation focuses on the definition of the research and calculation method set up to define, in parallel, the water consumption of an urban district and the energy consumption necessary to satisfy water requirements and CO2 emissions. Starting from the application of the calculation method in an existing urban district in Rome, 10 indicators of quantities have been developed to define water and energy consumption and their related CO2 emissions, focusing on the obtained results to also define some interventions to reduce water and energy consumption and CO2 emissions in territories that suffer a medium-risk impact from contemporary climatic conditions.