World Bank forecasts indicate that around four billion tonnes of waste will be generated by 2050 – around 60 percent more than today. The lion’s share is attributable to industrialized countries. In those regions, no industry generates more waste than the construction sector. During conversion or demolition work, materials such as concrete, plaster or gravel usually end up in landfills, even though they are urgently needed in new construction projects and cost a lot of money. The switch to a circular economy is aimed at putting a stop to this. The problem: “At present, not even ten percent of new and existing buildings are designed for deconstruction. For re-use to work seamlessly, we first need transparency about what goes into our buildings in the first place, and what we can do better to reduce carbon dioxide emissions and primary materials. That is why we need Circularity Passports for buildings across the whole country,” says Dr. Peter Mösle, Managing Director at the environmental consulting institute ENPA. He and his team design Circularity Passports for all types of buildings. ENPA is a subsidiary of Drees & Sommer, a company that advises on construction and real estate. The environmental consultants have now analyzed around 50 building types in a unique appraisal, deriving key findings for their design throughout Germany.
Eight years ago, ENPA started developing materials passports referred to as ‘Circularity Passport – Buildings’. All owners who at this stage produce this type of digital Circularity Passport for buildings, as demanded by the Federal Minister for Housing, Urban Development and Building, Klara Geywitz, for this legislative period, are ahead of their time. This is because the regulations planned in Europe and Germany will sooner or later force the industry to re-use materials – and to use a building as a storehouse of raw materials for new buildings when it is demolished.
“The introduction of digital Circularity Passports will change the construction industry as fundamentally as the introduction of energy performance certificates (epc) did twenty years ago, because for the first time, resource conservation and re-usability will become mandatory criteria in the choice of materials. To achieve this, we need to harmonize the different models that have been available on the market so far. Close cooperation with the Madaster registry of materials is already in place. However, what we urgently need is a legal framework with a uniform standard,’ pointed out Peter Mösle.
According to Pascal Keppler, who heads the digital services at EPEA, the following categories should definitely be included in a Circularity Passport for a property: CO2 footprint / environmental life cycle assessment, materials types and quantities, proportion of materials from renewable or recycled sources, pollutant content, re-usability, extent to which materials can be separated, and ease of dismantling the components. The circularity expert Pascal Keppler was very much involved in the development of the resources passports. A key finding of the appraisal is that solid building components such as reinforced concrete have the greatest impact on the overall result in the Circularity Passport. “The use of reinforced concrete (RC) aggregate (composite), recyclable support systems, low-CO2 cement, reinforcing steel or renewable CO2 storage materials such as timber in construction projects will achieve a very good result in the Circularity Passport. At the same time, alternative load-bearing structures are not a guarantee of good results in the Circularity Passport. To achieve this type of result, it is also necessary to select products with high materials-related health and re-usability. Optimization based purely on material type is not sufficient in this case,” explained Pascal Keppler and summed up the core results of the evaluation.
Birth of the Materials Passports – the EU Funded BAMB Research Project
It all started in 2015 with an EU funded research project. The project, named Buildings As Material Banks or BAMB, was intended to usher in a paradigm shift for the construction industry. For the first time, the focus was on the circularity approach for construction products and buildings. Pascal Kappler commented: “The ‘material cycle’ in our industrial society is really a one-way street. Raw materials are mined, processed, used and ultimately disposed of. So in waste management, we speak of downcycling and the ‘cradle to grave’ principle. This contrasts with the ‘cradle to cradle’ approach, in which we design products from renewable sources such that they can circulate in potentially infinite cycles without any loss of quality.”
This is often difficult to achieve with traditional building products. In conventional composite thermal insulation systems, for example, up to 20 different materials are bonded together inseparably, leaving nothing but hazardous waste. This means that raw materials go from the cradle to the grave. This contrasts with certified re-usable building materials, which not only conserve resources but also maintain the value of the constituent materials. “At 20 to 30 percent, a significant portion of gross construction costs is in the materials. If the materials used can be recovered at the end of their useful life and then form the basis for new, high-quality products, a significant part of this value is retained,” said Dr. Mösle. According to him, Circularity Passports – and the assessment of the financial value via Madaster platform –are needed for exactly this reason.
Life Cycle Approach Turns Resource Graves into Depositories of Raw Materials
Since the beginning of the EU funded project, EPEA has issued more than 100 resource passports and continuously further developed them. “High scores are awarded if materials either come from renewable sources such as sustainable raw materials, or if they have already been used in construction as secondary raw materials and are now being given a new lease of life,” explained EPEA’s Managing Director. He deliberately does not want to refer to this type of ‘re-use’ as ‘recycling’: “Current legislation considers downcycling or ‘energy recovery’ (such as burning wood) as recycling. But this is anathema to climate protection and resource conservation. For this reason, in the Circularity Passport we assess materials based on their potential for re-use. The assessment takes into account whether we can separate them into raw materials of the same kind, deconstruct and re-use them during conversion or demolition. We refer to this as ‘industrial re-use’.” Buildings are thus transformed into valuable depositories of raw materials that release their materials for new projects at the end of their useful life. The carbon footprint is also evaluated in Circularity Passports. Few people are aware that heating, hot water supply and electricity requirements for ventilation and lighting account for only half of the total CO2 emissions in most of today's new buildings.
The other half is due to the production and transport of building materials, including deconstruction and disposal. The Circularity Passport also includes this ‘gray energy’ in order to report on buildings over their entire life cycle.
Resources Passport as a Planning Instrument
This information is helpful not only for documentation, but also for environmentally compatible planning. The Circularity Passport shows its potential for optimization especially in the ‘materials origin’ category. Only some metals, such as the reinforcing steel, are usually made from secondary materials in new buildings. This does not even represent 10 percent. Yet if the Circularity Passport is used for planning over the entire life cycle, figures above 40 percent are now quite possible. “The measurable parameters enable planning teams to optimize their buildings in line with circularity aspects,” commented Pascal Keppler, who among other projects, also participated in the construction of Drees & Sommer’s new office building OWP12 in Stuttgart, Germany.
Almost every beam, every door, and even small-scale materials such as adhesives have been included in the reporting for the net plus energy building on the Drees & Sommer campus. To make this amount of information manageable, the data is linked to a digital twin. Distinct traffic-light color scales represent the building products visually and help to assess them before installation. If the separability of materials is not, or not yet, sure, the component is shown in red or yellow. Re-usable components are displayed in red color. Several improvements, in line with the Cradle to Cradle design principle, were made on Drees & Sommer’s new office building. And in September 2023, the property obtained a Platinum certification from the German Sustainable Building Council (DGNB).
Measurable Target Ratios Are Needed for Digital Resources Passports
The German government plans to introduce the Circularity Passport before the end of this legislative period. By then at the latest, the Cradle to Cradle design principle will be required for funding, financing or certification in many cases. According to Peter Mösle, clearly defined target ratios must be defined for robust legislation, following the example of the energy performance certificate: “With regulatory requirements in mind, demand for circular design is already on the rise. To further boost the turnaround in the way raw materials are used, at least 40 percent of all materials in new buildings should come from renewable raw materials or secondary materials by 2030, whether for new construction or for renovation. This rate can usually be achieved in existing buildings by maintaining the foundations and load-bearing structures.” It must also be possible to return all new materials into high-quality cycles at a later stage.
The Managing Director is of the opinion that re-use ratios should be introduced for all newly designed building materials in a way that all new materials can be used again in line with high-value circularity: “To this end, manufacturers in particular are asked to adapt their business models by developing their products in line with eco-design criteria and applying industrial re-use. By doing so, we are bringing regional added value back to Germany and Europe, while at the same time reducing dependence on imported raw materials. Our ecological problems will not simply disappear with a ‘business as usual’ approach. If we do not want to ruin our own future, we need to act now and establish a truly circular economy based on the Cradle to Cradle principle,” adds Peter Mösle.
About the Report:
EPEA has been using an internal database to report on all environmental life cycle assessments and Circularity Passports since 2021. Due to the diversity and heterogeneity of the projects covered, attributes were recorded for quality assurance of the sample. To do so, the projects were asked to provide information on the planning status and degree of detail, the scope of reporting on the modeling, and the type of consulting services. EPEA evaluated at random 48 buildings, of which 23 office complexes and 12 residential properties.
The report can be found here: Download report