Towards a Circular Built Environment – Lessons from the Netherlands
Rapid urbanization and a growing world population has exerted unsustainable pressures on the environment, exacerbating climate change through unrestrained material usage and greenhouse gas (GHG) emissions. Since the turn of the century, transitioning to a circular economy (CE) has been seen by policy makers as a potential solution for resource scarcity and climate mitigation. A CE aims to keep materials and products performing at their highest performance level using strategies such as recycling, remanufacturing, and reuse. Cities, which possess a high density of human activities, material stock, and waste production, are major contributors to emissions. This is especially true due to the concentration of construction activities in cities – the industry is responsible for 38% of CO2 emissions and 40% energy consumption globally. On the other hand, cities can also facilitate the implementation of circular strategies, thanks to increasing availability of data on space, people, and materials in cities. The transition to such an economy necessitates an understanding of the locations and scales material flows—an endeavour for which we are increasingly equipped due to the rapid digitalization of society. Through harnessing the vast amounts of data now available, we have an unprecedented opportunity to generate insights into our economies’ spatial and material dimensions.
This contribution will focus on giving an insight in actual approaches in the Netherlands regarding the transition towards a ‘Circular Built Environment (CBE)’; “a system designed for closing resource loops at different spatial-temporal levels by transitioning cultural, environmental, economic & social values towards a sustainable way of living (thus enabling society to live within the planetary boundaries)” (CBE-Hub TU Delft, 2023). In the Netherlands, through a government and nation-wide program a CE is aimed for to be reached by 2050. The ambition is to realise this with a variety of stakeholders, with an interim objective of realising a 50% reduction in the use of primary raw materials (minerals, fossils and metals) by 2030. It highlights economic opportunities because of the required transition, instead of emphasizing limitations, while also making the country less dependent on import of scarce raw materials and contributing to a cleaner environment.
This contribution will focus on the built environment. It will do so too, through several recent (European) research projects in which aspects of this were studied, from the scope of the TU Delft CBE Hub. This includes a range of foci, or as the CDE Hub states it a ‘scales to aspects’ range. This implies starting from materials and components, the base ingredients of buildings, to buildings as assemblies of large amount of building products, materials and components, and how they relate to circular performance. One step up, neighbourhood scale represents how circularity currently manifests in specific areas or districts. Cities’ scale explores the most important resource flows that enter, circulate and leave the urban environment every day. Finally, regional scale refers to the characteristic of the urban (or: territorial) metabolism and the importance to investigate economic activities to identify the flows and stocks of materials, products and waste.