Abstract
The implementation of the principles of the circular economy can significantly reduce the embodied emissions of building materials and is shown by many EU-funded projects aiming at a 50% reduction. This is a significant issue because the construction sector is responsible for more than 40% of the primary energy consumption in Europe, and 36% of the European carbon footprint (Eurostat, 2020).
To tackle this problem, the traditional approach has been based on the application of energy efficiency strategies that are able to significantly reduce the operational energy consumption of buildings. This solution is generally effective, particularly in the case of constructions built in the absence of any energy regulation and with poor construction quality (Asdrubali et al., 2019). Currently, the target of the most ambitious retrofit interventions is that of the Nearly Zero Energy Building, that represents the standard for new construction in Europe. However, when the operational energy demand is reduced and renewable energy systems are integrated in buildings to balance the residual energy requirement, it is possible to detect a significant burden shifting on the embodied energy and embodied GHG emissions (Asdrubali and Grazieschi, 2020).
This is why the attention of this research is focused on low carbon construction materials and the circular economy strategies that can reduce the embodied impacts of building systems and components. In order to support the reduction of the whole-life carbon of buildings the EU has already published several studies and directives, such as the Energy Performance of Buildings Directive (EPBD), the Energy Efficiency Directive (EED), the Waste Management Directive, the Green Product Procurement Directive (GPP), Ecodesign Directive of the Taxonomy Directive (European Commission, 2021, 2020; World Green Building Council, 2022). Furthermore, environmental certification schemes are expanding to support the diffusion of products and design practices that are able to reduce buildings’ embodied emissions: PEF – OEF, EPD, ecolabel, EMAS. In 2018 the European Commission launched Level(s), a common framework to assess the sustainability performance of buildings. Level(s) adopts a life-cycle and circularity approach to guide the construction sector towards environmental sustainability goals. In this regard, the first macro-objective of Level(s) (described as ‘greenhouse gas emissions along a building’s life cycle’) focuses on the operational stage energy performance to reduce the life-cycle Global Warming Potential of buildings.
The second macro-objective of Level(s), (’resource efficient and circular material life cycles’) examines indicators related to the circular utility and efficiency of materials and the measures required to move away from a traditional linear model to shifting the burden on embodied impacts.
This Overview article outlines some approaches European initiatives regarding circularity and low-carbon building materials in the construction sector.