Embodied Carbon Research Articles

Embodied carbon of BIM bridge models according to the application of off-site prefabrication: Precast concrete applied to superstructure and substructure

Embodied carbon (EC) changes of bridges using PC and RC, were analyzed using BIM and One-Click LCA. Identically shaped, concrete bridges (RC, PC, superstructure-only PC, and substructure-only PC) were modeled; the bills of quantity were extracted and input into the LCA software for EC comparison. As a result, it was found that applying PC instead of RC is not necessarily a guaranteed method to reduce the EC of bridges. Sensitivity analysis on the EC according to concrete waste and material transportation distances of all models were conducted. References from a carbon perspective were presented for applying PC separately to superstructure and substructure. As a result, solutions for the application of PC were derived considering the changes in concrete waste and transportation distance of concrete inputs. Conclusively, it was analyzed that substructure-only PC is effective in reducing EC overall, regardless of the amount of concrete waste and transportation distance of inputs.

Analysis of carbon emission characteristics and establishment of prediction models for residential and office buildings in China

Intensifying environmental issues make carbon reduction crucial, especially in the construction industry. Embodied carbon emissions (ECE) in buildings characteristically involve concentrated, intensive emissions over a short period. Implementing energy-saving and carbon-reducing technologies has raised ECE rates. Therefore, analyzing carbon emission (CE) characteristics during the production and construction phases is necessary. Currently, essential data on ECE is lacking, the calculation methods are complex, and ECE's characteristics and influential factors in residential and office buildings remain unclear. Moreover, there is a lack of prediction models for ECE in the construction phase that apply to current construction methods and CE factors. The research on prediction models for ECE has primarily focused on the production phase but has paid little attention to the contribution of non-structural materials to embodied carbon (EC). In this study, reinforced concrete residential and office buildings in hot summer and cold winter regions (located in the southeast part of mainland China, with a subtropical monsoon climate) were considered typical types, and the CE characteristics of two main phases, the production and construction phases, were analyzed. Based on critical features, such as the number of floors and the basement, prediction models for ECE in residential and office buildings were established at the design stage. The models were validated with mean absolute percentage error (MAPE) values below 4%, and coefficient of variation (root mean square error) (CV [RMSE]) values less than 0.02. The prediction models enabled a rapid estimation of ECE, encouraging designers to consider EC in the early design stages.

Systematic initial embodied carbon assessment of concrete modular high-rise residential buildings: A case in Hong Kong

Reducing carbon emissions from buildings is essential to achieving carbon neutrality. Modular construction (MC) has been adopted as an innovative approach to improve construction sustainability. However, detailed embodied carbon (EC) assessment of concrete modular high-rise residential buildings is lacking. This study aims to systematically assess the cradle-to-end-of-construction EC of concrete modular high-rise residential buildings. A multilevel EC assessment model was proposed and validated to assess the EC at different spatiotemporal levels. A concrete modular high-rise staff quarters building was selected for case study. Its cradle-to-end-of-construction EC was quantified as 569.3 kgCO2e/m2 with around 80 % from material production. The structural modules with structural walls generated more EC than the nonstructural modules. The residential area comprising the modules had higher EC emissions than the communal area. The case building generated 14.6 % less cradle-to-site EC from the production and transportation of structural materials but 20 % more cradle-to-end-of-construction EC compared with two prefabricated panelized building counterparts, respectively. The cradle-to-end-of-construction EC of the case building was reduced by 8.3 % by eliminating the nonstructural module floor and by 16.7 % by further decreasing the nonstructural module walls. The results show that concrete MC reduces the EC at the construction stage but does not necessarily achieve a lower initial EC than its conventional counterpart. Resolving the double-panel issues can effectively mitigate the EC of modular buildings. These findings demonstrate the effectiveness of the proposed multilevel EC assessment model and provide valuable insights for future research on the systematic EC assessment and reduction of modular buildings.

Development of a blockchain-based embodied carbon estimator

PurposeCarbon management in the construction industry plays a vital role as carbon emissions have a significant impact on the environment. Current emphasis on reducing operational carbon through passive designs, zero carbon buildings and so forth has resulted in losing focus on embodied carbon (EC) reduction. Though there are various databases and tools to estimate EC in construction, these estimates are lacking in accuracy and consistency. A Blockchain-based Embodied Carbon (BEC) Estimator was developed as a solution to accurately estimate EC using a supply chain value addition concept as a methodology.Design/methodology/approachThis study focused on developing, testing and validating the blockchain-based prototype system identified as BEC Estimator. The system was developed using Hyperledger Fabric following a waterfall model. Case studies and an expert forum were used to test and validate BEC Estimator.FindingsThe system architecture, development process and the user interface of BEC Estimator are presented in this paper. The comparative evaluation with existing EC databases/tools and the expert forum validated the functioning of BEC Estimator and proved it to be an accurate, secure and trustworthy EC estimating system. SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis identified the strengths and opportunities that will benefit the industry as well as the weaknesses and threats in the system that could be mitigated in future.Originality/valueBEC Estimator accurately accounts for EC additions happening at each supply chain node for any product that gets incorporated in a building, thereby facilitating EC-related decision-making for all relevant stakeholders.

On the Promise and Pitfalls of Optimizing Embodied Carbon

To halt further climate change, computing, along with the rest of society, must reduce, and eventually eliminate, its carbon emissions. Recently, many researchers have focused on estimating and optimizing computing's embodied carbon , e.g., from manufacturing, transporting, and disposing/recycling computing infrastructure, in addition to its operational carbon , e.g., from executing computations, primarily because the former is seemingly larger than the latter but has received less research attention. Focusing attention on embodied carbon is important because it can incentivize i) operators to increase their infrastructure's efficiency and lifetime and ii) upstream suppliers to reduce their own operational carbon, which represents downstream companies' embodied carbon. Yet, as we discuss, focusing attention on embodied carbon may also introduce harmful incentives, e.g., by overstating real carbon reductions and complicating the incentives for directly optimizing operational carbon. This position paper's purpose is to mitigate these issues by highlighting both the promise and potential pitfalls of optimizing embodied carbon 1 .

Topologically optimised facade brackets: an embodied carbon, structural and residual stress analysis

The research investigates the topological optimisation of the metal brackets that connect curtain wall panelling to the floor slabs of a building. As is typically the case with standard building components, the brackets are overdesigned with higher load margins than real applied loads. Optimising them results in reduced mass and a more evenly spread stress distribution. Correspondingly, the question that the project asks is whether the optimised designs have a comparable structural performance to the standard bracketry used in construction, and a lower embodied carbon. To answer this, several optimisations of a standard facade bracket are performed, resulting in a total of six converged design options, with three of them progressed for fabrication. The manufactured designs are then horizontal and vertical load and residual stress tested to assess their performance, and an embodied carbon analysis is performed to calculate the corresponding emissions for raw material extraction, processing, and component fabrication. The results indicate the presence of compressive yield magnitude residual stresses, and that structural performance is comparable to a standard bracket, but embodied carbon is in most cases higher. The paper concludes with a discussion of the findings, and possible next steps in the optimisation, structural testing, and embodied carbon analysis workflow.

Embodied Carbon Impacts of Building Envelope Systems

Abstract As buildings become more energy efficient due to stringent building codes, the emphasis on reducing the embodied carbon (EC) in the built environment has become significant. Studies predict that between 2020 and 2050, new buildings will surpass operational emissions with higher embodied emissions in their initial decade and throughout their life cycle. To meet decarbonization targets, reducing EC through low-carbon, high-performance building designs and grid decarbonization is crucial. This research analyzes the embodied carbon intensity of 26 commonly used envelope systems of large buildings in Ontario’s Greater Toronto and Hamilton Area (GTHA) using the attributional life cycle assessment (ALCA) methodology. Results highlight the impact of cladding materials, insulation layers, and backup structures on EC. The study ranks envelope assemblies based on their EC intensity (ECI), providing insights for designers to balance operational and embodied emissions. Noteworthy findings include the relatively high ECI of floor systems compared to exterior wall and roof systems. It also emphasized the challenges in assessing the environmental impacts of wood-based products and the need for uncertainty analysis and transparent reporting. The study contributes to understanding EC in building envelopes, guiding design teams toward low-carbon structures and more informed decision-making. As research progresses, recommendations include consequential analysis, assessing biogenic carbon impacts, and material durability studies for a deeper insight on the environmental impacts of building envelope materials.

Sustainable concrete structures by optimising structural and concrete mix design

ABSTRACT Sustainable concrete construction can be achieved by combining optimised structural designs with low-carbon concrete (LCC). This paper demonstrates the importance of sustainable construction by analysing various design options for a typical suspended slab system in high-rise buildings. Pearson (2020) noted that concrete slabs make up approximately 47% of the embodied carbon (EC) in commercial and residential structures, with slabs alone comprising around 70% of the total concrete volume in residential buildings. This presents an opportunity to reduce EC through structural design choices. The analysis in this paper involved designing a post-tensioned (PT) flat slab system for a residential development in Sydney and then re-designing it as a reinforced concrete (RC) slab by adjusting slab thickness and reinforcement system. A key finding was that transitioning from an RC to a PT slab resulted in a 44% total EC reduction when using a 100% General Purpose Cement (GPC) blend. Further EC reductions can be achieved by implementing LCC. The chosen LCC blend for this study is 23% Fly Ash, 23% Ground Granulated Blast Furnace Slag, and 54% Cement (FA/GGBFS/GPC), demonstrating a 36% reduction in EC compared to a 100% GPC blend while maintaining acceptable workability, constructability, mechanical, and durability properties.

Analyzing the environmental impact of conventional wooden and modern reinforced concrete construction systems

Abstract Anatolia is a homeland for many traditional construction techniques due to its rich historical background. One such technique is the hımış system, which involves filling a wooden frame with masonry material (brick, stone, and adobe). This construction method, commonly found in Anatolia, represents one of the most prevalent types of traditional houses. However, with the increasing adoption of reinforced concrete systems in modern construction, Anatolia’s buildings are now being constructed with concrete systems. This paper aims at comparing the embody energy use and carbon emissions of the traditional hımış system, compared to modern reinforced concrete systems. The findings of the study suggest that the total embodied energy per m2 of wall space in modern structures spans from 3000 to 1700 MJ/m2, in contrast to traditional structures where it ranges between 1200 and 300 MJ/m2. Furthermore, the range of total embodied carbon emissions in modern buildings is observed to be between 320 and 120 CO2kg-eq/m2, while in modern structure systems, it varies from 150 to 20 CO2kg-eq/m2. This inconsistency underscores the environmental advantages of traditional building techniques over their modern counterparts in terms of both embodied energy and carbon emissions. The relative share of concrete significantly affected the results for modern systems, while the presence of lime plaster increased the environmental impacts of the hımış systems.

Comparison of Embodied Carbon Footprint of a Mass Timber Building Structure with a Steel Equivalent

The main purpose of this study is to quantify and compare the embodied carbon (EC) from the materials used or designed to build the Adohi Hall, a residence building located on the University of Arkansas campus in Fayetteville, AR. It has been constructed as a mass timber structure. It is compared to the same building design with a steel frame for this study. Based on the defined goal and scope of the project, all materials used in the building structure are compared for their global warming potential (GWP) impact by applying a life cycle assessment (LCA) using a cradle-to-construction site system boundary. This comparative building LCA comprises the product stage (including raw material extraction, processing, transporting, and manufacturing) plus transportation to the construction site (nodule A1–A4, according to standard EN 15804 definitions). In this study, GWP is primarily assessed with the exclusion of other environmental factors. Tally®, as one of the most popular LCA tools for buildings, is used in this comparative LCA analysis. In this study, the substitution of mass timber for a steel structure with a corrugated steel deck and concrete topping offers a promising opportunity to understand the GWP impact of each structure. Mass timber structures exhibit superior environmental attributes considering the carbon dioxide equivalent (CO2 eq). Emissions per square meter of gross floor area for mass timber stand at 198 kg, in stark contrast to the 243 kg CO2 eq recorded for steel structures. This means the mass timber building achieved a 19% reduction in carbon emissions compared to the functional equivalent steel structure within the building modules A1 to A4 studied. When considering carbon storage, about 2757 tonnes of CO2 eq are stored in the mass timber building, presenting further benefits of carbon emission delays for the life span of the structure. The substitution benefit from this construction case was studied through the displacement factor (DF) quantification following the standard process. A 0.28 DF was obtained when using mass timber over steel in the structure. This study provides insights into making more environmentally efficient decisions in buildings and helps in the move forward to reduce greenhouse gas (GHG) emissions and address GWP mitigation.

Cradle-to-gate embodied carbon assessment of green office building using life cycle analysis: A case study from Sri Lanka

One of the most significant contributors to the economies of many nations is the building and construction sector. However, this industry is one of the world's most significant contributors to greenhouse gas emissions. Hence, the concept of green building (GB) has emerged as the cornerstone of sustainable development. Even though GBs have a variety of advantages, the use of low-carbon materials is still lacking for both traditional buildings and green buildings in the Sri Lankan context, and energy-intensive building materials are responsible for 80% of the carbon emissions of the construction industry in the world. In Sri Lanka, buildings make up more than 70.9% of contracts and consume a significant amount of raw materials, and office buildings use 33% of the raw materials. Therefore, this research aimed to assess the embodied carbon (EC) of green office buildings and to provide potential measures to reduce the EC of buildings in Sri Lanka. Following the case study research strategy, the EC emission was calculated using the Life Cycle Assessment (LCA) method for an eight-storey Platinum-rated green office building in Sri Lanka. The results showed that the green office building had an EC 583.82 kgCO2e/m2 of the gross floor area. Reinforcement steel was found to be the significant EC material, contributing 47.88% of the total EC. In addition to that, ready-mixed concrete, cement block, plywood, and aluminium are the other highly intensive EC materials in this study. The findings showed that the use of low-carbon materials, materials minimising design, utilisation of reusable or recycled materials, utilisation of local or regional materials, and utilisation of eco-labelling materials are potential measures to reduce cradle-to-gate EC in the building construction industry in Sri Lanka.

Optimizing Concrete Grade for a Sustainable Structural Design in Saudi Arabia

Buildings and facilities undergo several stages: the product stage, the construction stage, the use stage, the end-of-life stage, and the recycling stage. The life cycle of any facility or building contributes to embodied carbon (EC) emissions. The product stage, also known as the cradle-to-gate stage (A1–A3), registers the highest emissions, estimated to account for 70% of the total environmental impact. The continuing population growth in Saudi Arabia necessitates urgent action to identify and implement solutions for reducing greenhouse gas emissions and mitigating environmental risks. This study investigates the optimal method to analyze the grade of concrete for specific structural elements (columns) in a particular work area, adhering to accurate and methodological standards outlined in the Saudi Building Code (SBC). The bill of quantities (BOQ) determined the amount of building materials for the structure considered in this study. Reliable embedded carbon coefficients (ECCs) for structural materials such as concrete and steel were determined following life cycle assessment principles. They were analyzed using the Inventory of Carbon and Energy (ICE; Version 2.0) and Global Warming Potential (GWP). The obtained values varied based on the components of each mixture. This study determined the cost of each concrete mixture and steel, selecting the optimal mixture based on both EC and material cost. Since the quantity of cement significantly affects EC emissions in a concrete mixture, it is essential to select appropriate plasticizers and concrete types. This study evaluated the C30, C40, C50, C60, and C70 mixtures. Among these, the C70 mixture demonstrated the best environmental impact and was the least expensive compared to the basic C40 mixture for the estimated quantities of concrete and steel. The estimated reductions in cost and environmental impact were 33% and 27%, respectively. This groundbreaking study paves the way for low-carbon structural design in large hotels across Saudi Arabia, offering valuable insights for future projects and contributing significantly to energy conservation.

A Parametric Integrated Design Approach for Life Cycle Zero-Carbon Buildings

Implementing net-zero carbon design is a crucial step towards decarbonizing the built environment during the entire life cycle of a building, encompassing both embodied and operational carbon. This paper presents a novel computational approach to designing life cycle zero-carbon buildings (LC-ZCBs), utilizing parametric integrated modeling through the versatile Grasshopper platform. A residential building located at the New York Institute of Technology, optimized to fulfill the LC-ZCB target, serves as a case study for this comprehensive study. Four main influencing design parameters are defined, and three hundred design combinations are evaluated through the assessment of operational carbon (OC) and embodied carbon (EC). By incorporating biobased materials in the design options (BIO) as a replacement for conventional insulation (OPT), the influence of biogenic carbon is addressed by utilizing the GWPbio dynamic method. While both OPT and BIO registered similar OC, with values ranging below 0.7 kg CO2eq/m2a, the EC is largely different, with negative values ranging between −0.64 and −0.54 kg CO2eq/m2a only for BIO alternatives, while the OPT ones achieved positive values (2.25–2.45 kg CO2eq/m2a). Finally, to account for potential climate changes, future climate data, and 2099 weather conditions are considered during the scenario assessments. The results show that OC tends to slightly decrease due to the increasing productivity of PV panels. Thus, the life cycle emissions for all OPT alternatives decrease, moving from 2.4–3.0 kg CO2eq/m2a to 2.2–2.4, but none of them achieve the LC-ZCB target, while BIO alternatives are able to achieve the target with negative values between −0.15 and −0.60 kg CO2eq/m2a. There is potential for achieving LC-ZCBs when fast-growing biobased materials are largely used as construction materials, fostering a more environmentally responsible future for the construction industry.

Downsizing and the use of timber as embodied carbon reduction strategies for new-build housing: A partial life cycle assessment

The 2050 decarbonization goals coupled with the growing housing shortage in Europe intensify the pressure on new-build dwellings to enhance their energy performance. Beyond a zero operational energy, the focus has shifted towards reducing embodied carbon (EC). Against this backdrop, this study investigates the simultaneous impact of downsizing and the use of timber in new-build dwellings, EC reduction strategies seldom explored concurrently. Through partial life cycle assessments, three scenarios are modelled: the Small, Medium, and Large House, with two construction variations for each, comparing a modular timber design to a conventional concrete alternative. Designs are based on dwellings built in Almere, the Netherlands. Data is extracted from the Swiss Ecoinvent database using the TOTEM tool and the static −1/+1 approach for biogenic carbon accounting is adopted. Results show a total EC ranging from 42,608 to 70,384 kgCO2eq for the timber designs versus 54,681 to 91,270 kgCO2eq for their concrete counterparts. Findings suggest that the relationship between house size and EC is sublinear whereby a house twice the size entails less than twice the EC emissions. Only the simultaneous implementation of downsizing and the use of timber achieved 53% carbon savings. The discussion explores implications of outcomes across academic, industry and policy perspectives, challenges in implementing smaller timber dwellings, and study limitations and future research. Beyond its empirical contribution, this paper offers a practical contribution with its hierarchical data analysis approach covering building, element and component. This approach can be implemented by researchers and practitioners alike to inform their design process.

Influence of urban density on energy retrofit of building stock: case study of Spain

ABSTRACT Energy retrofitting of existing buildings plays a key role in the European targets of Green House Gas reduction. The addition or substitution of construction materials is needed to improve energy performance of buildings and its environmental impact must be considered. This paper proposes a model for the assessment of the environmental impact of neighborhood retrofit in relation with urban density. The model is based on the decomposition of buildings into functional elements and the quantification of construction materials used in building energy retrofitting. As a novelty, the need of road rehabilitation was also considered. The environmental impact was assessed in terms of Embodied Energy (EE) and Embodied Carbon (EC). The operational energy after retrofit was also calculated. The results bring the evidence of the relation between the urban density and the EE and EC derived from building retrofit, which can be up to 60% higher in low density areas. The sensitivity analysis carried out demonstrates the influence of the urban compactness on the environmental assessment results. The model proposed can assist in the design of retrofit plans at urban level by highlighting those retrofit measures with most significant environmental impact depending on the urban density.

Embodied impacts of buildings from energy-carbon-water nexus perspective: A case study of university buildings

Despite extensive investment in energy efficiency efforts, the energy footprint of the building sector still contains over 40 % of the world's annual consumption of energy. Although most of a building's life cycle energy use comes from operational activities, a portion of it stems from embodied energy (EE), which is directly expended in a building's construction and indirectly consumed using materials. Because each material consumes not only different amounts but also different types of energy sources, studying embodied carbon (EC) is equally important. The building construction sector also consumes nearly 1/5th of global fresh water, which is becoming a grave concern, given the increasing frequency of droughts and wildfires. The fact that material manufacturing and construction processes also consume water makes it essential to not just assess energy and carbon but also embodied water (EW). The literature recommends evaluating total EW including direct and indirect EW as well as any EW associated with EE use. In this paper, macroeconomic models are utilized to compute and analyze the energy, carbon emission, and water embodied in four university buildings. The results show that the total EE, EC, and EW values for the four case study buildings vary from 13.1 to 51.1 GJ/m2, 1.4–10.0 kgCO2/m2, and 2,820–12,900 gal./m2, respectively. The EE values also show a near perfect positive correlation with EW values. However, the share of EREW in the total EW ranges from 13 % to 16 %, indicating that a decrease in EE use may not help decrease a majority of EW.

Life Cycle Assessment of the Construction Process in a Mass Timber Structure

Today, the application of green materials in the building industry is the norm rather than the exception and reflects an attempt to mitigate the sector’s environmental impacts. Mass timber is growing rapidly in the construction field because of its long span, speed of installation, lightness and toughness, carbon sequestration capabilities, renewability, fire rating, acoustic isolation, and thermal resistance. Mass timber is close to overtaking steel and concrete as the preferred material. The endeavor of this research is to quantitatively assess the ability of this green material to leverage the abatement of carbon emissions. Life cycle assessment (LCA) is a leading method for assessing the environmental impacts of the building sector. The recently completed Adohi Hall mass timber building on the University of Arkansas campus was used as a case study in an investigation to quantify greenhouse gas (GHG) emissions throughout the construction phase only. The energy used in building operations is the most dominant source of emissions in the building industry and has galvanized research on increasing the efficiency of building operations, but reduced emissions have made the impacts of embodied carbon (EC) components more noticeable in the building life cycle. While most studies have focused on the manufacturing stage, only a few to date have focused on the construction process. Consequently, few data are available on the environmental impacts associated with the installation of mass timber as a new green material. The present study began with the quantification of the materials and an inventory of the equipment used for construction. Then, this study determined the EC associated with running the equipment for building construction. The GHG emissions resulting from the transportation of materials to the site were also quantified. Based on data collected from the construction site, the results of this study indicate that earthwork ranks first in carbon emissions, followed by mass timber installation and construction. In third place is ready-mix poured concrete and rebar installation, followed by Geopiers. A comparison of these results with those in the existing literature shows that the EC generally associated with the building construction phase has been underestimated to date. Furthermore, only emissions associated with the fuel usage of the main equipment were considered.

Use of SCM in Manufacturing the Compressed Brick Optimizing Embodied Energy and Carbon Emission

Brick is one of the most used building materials in masonry construction. Conventionally burnt clay bricks are used. These bricks are manufactured from clay and burnt in a kiln at a higher temperature. This results in a very high amount of CO2 emission and has high embodied energy, which highly affects the environment. Compressed bricks are one of the sustainable solutions to overcome these issues of high CO2 emission and embodied energy. Adopting sustainable alter- natives, such as compressed bricks incorporating supplementary cementitious materials or envi- ronmentally friendly brick manufacturing processes, can help mitigate these issues and promote more sustainable construction practices. In this study, attempts have been made to manufacture and test the bricks with different proportions of the soil, i.e., the mix of locally available soil with sand, cement as the cementitious materials, and SCMs like fly ash & GGBS. The research methodology involves the formulation of different mixtures with varying proportions of SCMs. The specimens were then prepared using a compression molding technique and cured under controlled conditions. This research paper aims to investigate the effects of incorporating sup- plementary cementitious materials (SCMs) on the properties of compressed bricks. The study focuses on evaluating the density, compressive strength, water absorption, and efflorescence, as well as calculating the embodied energy and carbon dioxide emissions associated with the pro- duction of these bricks. Furthermore, the paper comprehensively analyzes the embodied energy and CO2 emissions associated with producing compressed bricks. These calculations consider the energy consumed and CO2 emitted in manufacturing, including raw material extraction, transportation, and brick fabrication. The study's results demonstrate the influence of SCMs on the properties of the compressed bricks. The analysis of embodied energy and CO2 emissions provided valuable insights into the environmental sustainability of the brick production process.

Building upcycling or building reconstruction? The ‘Global Benefit’ perspective to support investment decisions for sustainable cities

Investment decisions on demolition and reconstruction vs. refurbishment of the existing building stock can extend beyond financial and economic criteria. However, they must involve energy savings, environmental preservation, material consumption, and waste management for sustainable cities. The regulatory framework used in the past decades and the correlated research seem more unbalanced toward the containment of building energy consumption than toward embodied energy (EE) management in production processes and environmental impact management. Foreshadowing the perspective of a more restrictive regulatory framework on EE, such as prohibiting the displacement of materials with residual energy potential, such as waste in landfills, some challenging frontier issues are involved when facing the limits of the economic evaluation methodologies for transformation projects. Thus, this study aimed to propose a reasoning and an operative modality to support urban governance policies and investment decisions involving private and public subjects in the construction sector. Circular economy and life cycle thinking principles, through life cycle costing (LCC) and life cycle assessment (LCA), are assumed and harmonized with the discounted cash-flow analysis (DCFA): (1) monetizing and modeling into the DCFA the EE and the embodied carbon (EC); (2) internalizing the Global Cost and the new ‘Global Benefit’ into the net present value (NPV) calculation; and (3) focusing on the residual end-of-life value calculation from the early design and investment decision stages. The reasoning can be extended to single buildings, the urban scale, or even entire portions of existing buildings in urban areas concerning typological sub-segments. The operative modality is yet to be explored in a concrete application for orienting urban governance policies and sustainable public–private partnerships, including environmental and, thus, social externalities even in the private real estate investment decision process, in the scope of evolving regulations.

Embodied Carbon in Australian Residential Houses: A Preliminary Study

Embodied carbon is a buzzword in the construction industry. Australia is committed to achieving Net Zero 2050 targets, and minimizing embodied carbon (EC) is inevitable. Owing to the population growth, there will be a significant demand for residential construction. Therefore, the material consumption in residential construction should be evaluated and proper strategies should be in place to minimize EC. The aim of this research is to undertake a preliminary study of EC in the Australian residential sector, with an emphasis on new residential home construction. This research presents a preliminary study on EC in residential buildings in Australia. Three case study residential buildings were used in this study. All three case studies are single -story residential units, with a gross floor area between 200 and 240 m2. One Click LCA software was used to calculate the EC. The EC of three case study residential homes is between 193 and 233 kgCO2e/m2. Based on the findings of this study, ‘other structures and materials’ contribute to a large amount of EC in residential construction. Concrete and aluminum are considered significant contributors to EC. Therefore, it is vital to either introduce low-EC material to replace aluminum windows or introduce various design options to minimize the use of aluminum in windows. There are various sustainable concretes available with low EC. It is essential to explore these low-EC concretes in residential homes as well. This research identifies the importance of adopting strategies to reduce the carbon impact from other sources, including concrete. It is also essential to consider the EC through transportation related to construction and promote locally sourced building materials in residential construction. Therefore, the results of this research indicate the necessity of reducing raw material consumption in Australian residential construction by implementing approaches such as a circular economy in order to circulate building materials throughout the construction supply chain and reduce raw material extraction.