Bottom-up policy support

Abstract

Although the need for a more circular economy is supported by diverse people in both politics as well as in the scientific community, implementation of circular principles in reality is rarely occurring. This study shows how quantitative models can help to develop new policies for enhancing circularity in the construction sector. By means of a bottom-up construction materials model, an analysis of the circular opportunities for the Netherlands was developed. First of all, the national material stock in the built environment and their embodied environmental impacts were assessed. Next, the most important flows (being reinforced concrete, bricks, timber, aluminium and glass and copper) were subjected to an environmental quick scan. With this quick scan, potential alternatives for more circular end-of-life treatment routes could be compared and ranked by their effectiveness. The study was finalized by interviewing stakeholders about the political practicability of the outcomes and by defining recommendations for new policy development. In comparison to a business-as-usual scenario, the circular treatments of the selected materials show a reduction potential up to around 30% of the environmental impact over their full life cycles. When compared to the total national construction material demand in the coming years, considering all materials, these circular treatments could help to achieve a reduction of around 10%. The outcomes and the feasibility for implementation were discussed with stakeholders. The construction material model was based on generic and average construction practises, but even though this bottom-up approach is sensitive for assumptions, it proved to be a useful tool to start policy discussions thanks to its informative visualizations. The model can be further refined in case study projects, but it is yet ready to identify environmental hotspots and provide input for discussions about circular strategies.