Against this backdrop, the circular economy has emerged as one of the most promising sustainability strategies in construction. Rather than demolishing buildings and sending the debris to landfills, circular approaches emphasize deconstruction—carefully disassembling structures so that beams, slabs, blocks, and other components can be salvaged, reused, remanufactured, or recycled in new projects. In some cases, this can simultaneously reduce embodied carbon (the emissions associated with producing construction materials), divert waste from landfills, and lower project costs. Yet industry practitioners remain hesitant, and one reason stands out above the rest: uncertainty. Cost is consistently identified by professionals as one of the main impediments to adopting carbon-reduction measures, and salvaged materials introduce a host of unknowns that virgin products simply do not have.

That uncertainty has now been quantified. A new study published in the open-access journal Cleaner Engineering and Technology by Alberto E. Pozzer, Nikiforos Repousis, Fernanda Leite, and Christopher Rausch presents the first comprehensive framework for measuring the uncertainty in both embodied carbon and cost assessments for reclaimed construction products. The research addresses a glaring gap in the scientific literature. While previous studies have applied uncertainty analysis to the manufacturing of construction materials, to whole-building product stages, and even to full project lifecycles, none had extended that analysis to the end-of-life and “beyond-life” stages—where materials from one project are salvaged and given a second life in another.

The central hypothesis of the research was straightforward but consequential: reused products likely have a lower mean embodied carbon and cost compared with virgin materials, but they inherently carry higher variability. If that variability goes unmeasured, procurement decisions based on average values alone could be misleading, or even wrong. As the authors put it, quantifying this spread is essential to ensure “meaningful and transparent procurement decision-making.” The study also posed a follow-up question with real-world implications: does a higher level of uncertainty itself influence whether decision-makers choose circularity in the first place?

To model that uncertainty, the researchers turned to Monte Carlo simulation, a computational technique that has become the workhorse of uncertainty analysis in lifecycle assessment (LCA). Rather than producing a single deterministic estimate of embodied carbon or cost, Monte Carlo simulation treats key input parameters as random variables, each characterized by a probability distribution. The model then generates random samples from these distributions—10,000 iterations in this study, a figure consistent with prior research showing that results converge at that scale—yielding thousands of possible outcomes. From these, the team derived means, standard deviations, and full probability density functions describing the range of plausible results.

Identifying which variables to model was itself a substantial undertaking. Drawing on a scoping review of prior literature, the researchers distilled the uncertainty sources specific to salvaged materials into measurable variables across four scopes: project end-of-life, transportation, reclaimed material properties, and beyond-life pathways. At the project end-of-life stage, the uncertainty of the deconstruction schedule and the emission factors of the equipment used become critical, since deconstruction demands more detailed planning than conventional demolition, and studies have flagged risks such as inaccurate labor estimates, insufficient skilled workers, and inadequate heavy equipment. Transportation introduces variability in distances and vehicle emission factors. The reclaimed materials themselves bring perhaps the thorniest uncertainties: their quantity, their properties—which the team modeled as a binary pass/fail against required conditions—and their durability, expressed as an uncertain remaining service life. Finally, the beyond-life stage adds scenario alternatives (reuse, recycling, remanufacturing) and process emission factors.

The study adopted a pragmatic approach to characterizing these variables statistically. Using @RISK, a Microsoft Excel–based risk analysis tool, the team identified best-fitting probability distributions wherever sufficient data existed. Where data was sparse, they applied simpler distributions: uniform distributions when only minimum and maximum values were known, and triangular distributions when an expected value, minimum, and maximum were available. This flexibility matters, because previous work has shown that when Monte Carlo simulations exceed 10,000 iterations, results tend to converge regardless of whether inputs are characterized as normal, uniform, or lognormal—meaning the choice of distribution matters less than capturing the plausible range. For virgin materials, the team used the same uncertainty factors established in earlier studies of the product, transportation, and construction stages.

The lifecycle accounting followed ISO 14040 and ISO 14044 standards, organized into four stages: the product stage (A1–A3), covering raw material extraction, transportation, and manufacturing for virgin products; the use stage (B1–B5), covering maintenance, repair, replacement, and refurbishment for both virgin and salvaged materials; the end-of-life stage (C), covering deconstruction and transportation of reclaimed materials; and stage D, covering reuse and recycling. The embodied carbon equations summed material quantities multiplied by emission factors, equipment fuel consumption multiplied by fuel emission factors, and transportation distances multiplied by vehicle emission factors, with additional equations accounting for the project lifespan and the service life of reused components. The cost model mirrored the carbon model exactly, with emission factors replaced by unit costs—a structure aligned with traditional quantity-times-unit-price cost estimation. This parallel structure is significant, because cost estimates themselves suffer from uncertainty in cost data and gaps in project scope definition, yet cost uncertainty is rarely analyzed alongside carbon uncertainty.

To demonstrate the framework, the researchers built a case study anchored in real project data. The end-of-life data—schedule, equipment, transport logistics—came from a selective demolition project previously documented by Repousis, while emission factors were drawn from the OneClickLCA Building LCA software, an industry-standard tool containing a comprehensive repository of lifecycle inventory data and environmental product declarations. Equipment fuel consumption rates came from technical sheets and external sources. The beyond-life scenario was constructed by defining a hypothetical new project based on a masterplan, drawings, and specifications, allowing the team to simulate what would happen if the salvaged materials were incorporated into future construction.

The simulation results were then compared probabilistically. For each material alternative—new, reused, and recycled—the team computed the probability of not exceeding a reference embodied carbon and a reference cost established as project goals. This is the framework’s key innovation: instead of declaring one option “better” based on mean values, it tells decision-makers how confident they can be that a given option will actually meet their carbon and cost targets. A reused material with a lower average embodied carbon but wide variability may carry a lower probability of hitting a strict carbon target than a virgin material with a modest but tightly clustered footprint—and the framework makes that trade-off visible.

The significance of this work extends well beyond a single case study. The literature on concrete reuse illustrates why: reported carbon savings from reusing concrete elements have ranged wildly, from 40% to 82% across different studies, and some analyses of recycled aggregate concrete have even projected emissions increases rather than reductions. Case-specific studies—such as assessments of reusing concrete blocks for a pedestrian bridge, or repurposing beams, floors, columns, and hollow-core slabs—have demonstrated potential but never incorporated uncertainty analysis. Reviews of circular economy research have repeatedly flagged the lack of knowledge and data on the quality of recovered and recycled materials as a barrier to implementation, and have noted that the accuracy of LCAs for upcycling demolition waste is constrained by data uncertainty. Until now, however, no study had actually quantified that uncertainty.

The framework is also deliberately replicable. The authors emphasize that uncertainty sources in LCA are affected by geographical, temporal, and technological representativeness—emission factors vary by region, and practices for demolition, deconstruction, and transportation differ from one location to another. The value of the approach, therefore, lies not only in the results of this particular case but in providing a method that practitioners can adapt to their own projects, plugging in locally relevant input variables. There are limits, too: the study deliberately excludes supply chain and market dynamics—demand fluctuations, supplier availability—although the authors acknowledge these external factors as important candidates for future research.

What emerges is a practical answer to a question that has long haunted sustainable construction. Reused materials do tend to offer lower average embodied carbon and cost, but that advantage comes wrapped in variability that must be measured, not ignored. By quantifying that variability, the new framework gives architects, engineers, and contractors a way to weigh circular options with their eyes open—transforming salvage from a leap of faith into a calculated, transparent decision.

Denmark is spearheading this movement, having become the first nation to mandate stringent emissions regulations for new buildings. This forward-thinking policy has propelled Denmark to the forefront of Europe’s sustainable construction efforts, yielding rapid advances and substantial emission reductions within both manufacturing and construction domains. Despite these substantial achievements, the journey to a fully green construction sector requires moving beyond the initial gains—referred to metaphorically as “harvesting the low hanging fruits.” For further progress, intensified emphasis on research, development, and innovative solutions is crucial over the coming decade.

CEBE’s mission is deliberately ambitious: to cultivate cutting-edge knowledge, tools, and materials that collectively diminish the construction sector’s climate footprint while optimizing resource efficiency. Integral to the program’s success is an enhancement of educational standards and initiatives to entice fresh talent into this evolving field. By fostering a knowledgeable and skilled workforce, Denmark aims to simultaneously nurture scientific expertise and bolster industry readiness, ensuring that green construction principles are widely adopted and advanced within professional practice.

Committed to becoming a European exemplar in sustainable construction, the program embodies Denmark’s strategic vision for climate leadership. Per Heiselberg, Professor at Aalborg University and Programme Director of CEBE, articulated the global relevance of this endeavor, stressing the necessity for research outputs and innovations that transcend national boundaries. He highlighted Denmark’s existing strengths while expressing eagerness over the collaborative potential and transformative outcomes anticipated through the CEBE initiative.

This substantial undertaking is supported by an unprecedented allocation of resources: the Villum Foundation pledges a monumental one billion Danish kroner over ten years, marking its largest ever investment in research. Such funding reflects the foundation’s recognition that reducing construction’s environmental impact requires systemic change spanning from academic research and talent cultivation to tangible collaborations with industry stakeholders. The program’s holistic approach encapsulates a comprehensive ecosystem, aiming to drive sustainable evolution in the design, material production, construction processes, operation, and eventual reuse or recycling of built assets.

CEBE strategically integrates seven interdependent research domains, collectively addressing the lifecycle of built environments rather than fragmented components. This integrated methodology ensures innovations are not confined within academic silos but instead translate into practical, scalable solutions adaptable across varying contexts. From early design decision-making to long-term infrastructure management, these research fields synergize to effectuate measurable reductions in carbon emissions and environmental degradation.

The program’s first focus area involves developing precise analytical frameworks to assess and measure sustainability in construction comprehensively. This encompasses evaluating emissions and resource usage not only for new builds but crucially for extant infrastructure, leveraging dynamic models that inform sustainable interventions. These advanced assessment tools underpin evidence-based decision-making, enabling stakeholders to prioritize actions that align with stringent climate targets and sustainability mandates.

Another pivotal dimension emphasizes design principles oriented towards regeneration, circularity, and building longevity. Research here pioneers methodologies enabling buildings to contribute positively to ecological systems over time while maintaining indoor environments that are safe, healthy, and resilient to climatic variations. This vision extends to the development of modular, recirculatable components, ensuring that structures evolve through adaptive reuse and minimized waste, fostering genuine circular economy practices in construction.

A third critical area tackles the post-industrial challenge of radically lowering the carbon footprint associated with construction materials. Investigations encompass utilizing recycled and salvaged inputs while pushing innovation in novel regenerative materials that deliver comparable or superior durability and performance. Addressing this material dimension is fundamental given the sector’s vast consumption of embodied energy and resources, positioning material innovation as a decisive lever for emission reductions.

The incorporation of digitalization and automation is transforming traditional construction paradigms. CEBE explores advanced applications such as robotics, 3D printing, artificial intelligence, and computational modeling to optimize material use and advance precise carbon accounting. These technologies provide unprecedented opportunities to execute construction with minimal waste and energy consumption, while enhancing monitoring capabilities and facilitating responsive lifecycle management, thus accelerating the shift toward low-carbon practices.

Addressing the intensifying impacts of climate change on infrastructure, research into climate resilience and adaptive technologies is vital. This entails fortifying transportation networks, ports, and coastal defenses against severe weather events including storms, flooding, and cloudbursts. Nature-based solutions and innovative monitoring techniques complement upgrades to existing assets, enhancing predictive maintenance and emergency responsiveness—critical capabilities for sustaining societal functions amid increasing climate volatility.

The program also underscores the often-overlooked interplay between sustainability and human well-being. Reconceptualizing buildings as environments that simultaneously conserve energy and nurture occupant health, the sufficiency-focused research integrates considerations of indoor climate quality, thermal comfort, and resource efficiency. By optimizing these factors collectively, constructions can better support human productivity and quality of life while adhering to stringent environmental goals.

Finally, CEBE emphasizes the necessity of extending the lifespan of existing buildings as a quintessential sustainability strategy. Preservation, adaptive reuse, and sustainable renovation practices minimize the disruptive carbon emissions associated with new construction. Research develops robust methodologies for condition assessment, predictive lifespan modeling, and functional repurposing of structures, ensuring that visible and invisible value within the current building stock is leveraged more effectively and responsibly.

This ambitious program is not confined by national borders but actively pursues international collaboration and talent exchange to magnify its impact. Over 100 million kroner from the overall budget is earmarked for global partnerships, notably with the prestigious ETH Zurich. This transnational network facilitates knowledge sharing and accelerates the diffusion of innovative solutions across diverse economic and environmental contexts worldwide. By positioning Denmark as a nexus for international green construction expertise, CEBE aspires to drive systemic transformation on a continental and global scale.

The combined effect of research, education, and industry collaboration enabled by CEBE promises to reimagine the construction sector’s relationship with the environment fundamentally. As the program matures, it is expected to catalyze breakthroughs that redefine standards, inspire policy evolution, and provide actionable frameworks for sustainable urban development. Denmark’s model serves as an imperative example for other nations confronting the dual challenges of infrastructure growth and climate mitigation, demonstrating that proactive investment in knowledge and innovation can yield resilient, regenerative, and equitable construction futures.

In summary, the CEBE initiative stands as one of the most ambitious and comprehensive attempts worldwide to confront the climate crisis through transformative engineering and collaborative innovation in the built environment. Its success could herald a paradigm shift not only for Denmark and Europe but for the global construction industry, illustrating how research-driven capacity building, coupled with strategic foresight and international cooperation, can forge pathways toward a sustainable and climate-resilient built future.

Subject of Research: Sustainable Construction and Green Transition in Civil Engineering

Article Title: Denmark’s CEBE Program: Pioneering the Green Transition in Global Construction

News Publication Date: Not specified (Official launch date February 26, 2026)

Web References: www.cebe.dk

Keywords

Building construction, Architecture, Climate change, Sustainable construction, Green transition, Low carbon materials, Circular economy, Climate resilience, Digitalization in construction, Environmental impact assessment