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Fifth-generation district heating and cooling (5GDHC) systems have the potential to provide simultaneous heating and cooling, allowing for energy exchange between users with different needs. However, their viability in mild climates with a higher share of cooling demand remains unclear. In this paper, we propose a framework for assessing the engineering, economic and environmental performance of a 5GDHC system compared to a state-of-the-art business-as-usual solution and demonstrate it through a practical case study for a university campus in Melbourne, Australia. When accessible heat sources and sinks are available, the 5GDHC system provides a cost-effective solution, with annual cost savings between 9 and 29 % and GHG emissions reduction between 25 and 58 % compared to an already advanced business-as-usual system. Additionally, by using peak off-peak tariffs and an hourly emission factor for the electricity consumed, we demonstrate the 5GDHC operational flexibility in pursuing different objectives, such as minimising cost or emissions, respectively. The results suggest that 5GDHC systems are an economically and environmentally viable solution in milder climates, and a successful implementation of 5GDHC in Australia can create new market opportunities and pave the way for its adoption in other countries with similar climatic conditions and no established history of district heating systems.

In recent years, many novel smart technologies have been proposed to reduce the energy consumption and greenhouse gas (GHG) emissions attributed to the building sector. One such application of these technologies is the reduction of the Heating, Ventilation and Air Conditioning (HVAC) energy needs and GHG emissions using smart control systems. The environmental benefits of smart control systems during building operation have been explored in many studies, however, their embodied effects, associated with the extraction of raw materials, manufacturing and replacement are often overlooked. Accordingly, this study quantifies the life cycle energy needs and GHG emissions of a smart HVAC control system and assesses its potential for reducing the HVAC operational energy and GHG emissions in an Australian office building. A comparative assessment is performed, considering a traditional HVAC control system and an equivalent smart HVAC control system. The components of both the traditional and smart control systems are specified based on the characteristics of these systems as well as the layout of the serviced spaces in the reference building. The embodied energy and GHG emissions of both the traditional and smart control systems are quantified through a hybrid life cycle inventory (LCI) approach. To evaluate the effects of these control systems on the building HVAC operational energy, a building energy simulation is performed by applying the control logics of both systems. The results show that energy and GHG emissions savings in the HVAC operational offset the additional energy needs and GHG emissions of deploying the smart HVAC control system.

Reducing the embodied environmental flows of built assets is becoming increasingly important and is a key priority for actors in the built environment to improve life cycle environmental performance. Policies and related targets for embodied environmental flow reductions are emerging. Despite this, tools for quantifying the life cycle embodied environmental flows of built assets are limited in variety and scope. Parametric life cycle assessment (LCA) tools have emerged to address some of these limitations. These tools can enhance decision making, be embedded directly into CAD programs, and offer real-time LCA calculations across multiple design variations. Yet, existing parametric tools for LCA rely on process-based material environmental flow data, limited geometries, limited real-time data visualisation capacity, and often require specialised technical expertise to use. These gaps limit their ability to provide transparent, robust, and rapid assessments. This paper introduces EPiC Grasshopper, an open-source, open-access, bottom-up, parametric tool that enables the quantification of life cycle embodied environmental flows at the early stages of built asset design, bridging the aforementioned gaps. The key characteristics and functionalities of the tool are described, followed by verification (checking that calculations are correct), validation (checking that results are representative of reality), and demonstration of its application to two built asset case studies, i.e. parametrically-defined Australian house and road. The paper shows how the tool can be used to generate designs to meet specific embodied environmental flow targets as well as streamline and increase the uptake of embodied environmental flow assessment and considerations in built asset design workflows.

To reduce the environmental effects caused by building construction and operation, life cycle assessment (LCA) is increasingly applied. In recent years, national building regulations have implemented LCA requirements to support building life cycle impact reduction. A key element in these regulations are environmental benchmarks which allow designers to compare their building designs with reference values. This study aims to develop bottom-up life cycle environmental benchmarks that represent the range of environmental impact results achieved with conventional construction in Flanders, Belgium. For this purpose, the study investigates the potential of using a database of building energy performance calculations. Specifically, this study considers 39 residential buildings identified as representative of the Flemish energy performance of buildings database of 2015–2016, applying modifications to establish scenarios that are still relevant in 2025. The buildings are assessed with the Belgian LCA tool TOTEM to calculate an aggregated environmental score based on the European product environmental footprint (PEF) weighting approach and including 12 main impact categories. In addition to the aggregated score, the climate change (CC) indicator is analysed individually. In view of the benchmarks, variations were applied to the 39 original buildings in terms of heating system and materialisation. The variation in heating system included changing gas boilers to electric heat pumps to comply with upcoming (2025) Flemish building regulations. The variations in building materials included three sets of conventional Flemish building element compositions that were applied to generate a wider spread of impact results as a basis for benchmarks. Benchmark values were derived through a statistical analysis of the 117 modelled variants: a best-practice value (10th percentile), reference value (median) and limit value (90th percentile). For the environmental score, the benchmark values a

Purpose: Recently, there has been a shift toward the embodied energy assessment of buildings. However, the impact of material service life on the life-cycle embodied energy has received little attention. We aimed to address this knowledge gap, particularly in the context of the UAE and investigated the embodied energy associated with the use of concrete and other materials commonly used in residential buildings in the hot desert climate of the UAE. Design/methodology/approach: Using input–output based hybrid analysis, we quantified the life-cycle embodied energy of a villa in the UAE with over 50 years of building life using the average, minimum, and maximum material service life values. Mathematical calculations were performed using MS Excel, and a detailed bill of quantities with >170 building materials and components of the villa were used for investigation. Findings: For the base case, the initial embodied energy was 57% (7390.5 GJ), whereas the recurrent embodied energy was 43% (5,690 GJ) of the life-cycle embodied energy based on average material service life values. The proportion of the recurrent embodied energy with minimum material service life values was increased to 68% of the life-cycle embodied energy, while it dropped to 15% with maximum material service life values. Originality/value: The findings provide new data to guide building construction in the UAE and show that recurrent embodied energy contributes significantly to life-cycle energy demand. Further, the study of material service life variations provides deeper insights into future building material specifications and management considerations for building maintenance.

Many smart technologies have been introduced in buildings with the aim to reduce the energy and GHG emissions associated with their operation, particularly through improved control systems for regulating heating, ventilation and air conditioning (HVAC) equipment. Despite their energy saving potential, only a few studies have comprehensively assessed the costs associated with their practical implementation from a life cycle perspective. Accordingly, this study quantifies and compares the life cycle costs of a smart HVAC control system with that of a traditional control system, in the context of an Australian office building. For both systems, the required hardware are specified based on the characteristics of these systems and the layout of the serviced spaces in the reference building. The costs incurred over the period of assessment are quantified using the net present cost (NPC) approach. To evaluate the effects of these control systems on the operational energy costs of the building HVAC system, the control logics of both these systems are modelled through building energy simulations. The results show that, over the period of assessment, the smart control system incurred a higher total cost compared to the traditional control system. However, the findings from the simulations show that the HVAC energy cost savings achieved through the specification of the smart control system offset the additional cost incurred to deploy this system over the traditional control system. The smart control system resulted in HVAC operational cost savings between 9 % and 10 % compared to the traditional control system. Sensitivity analyses indicated that the total life cycle costs varied between −27 % and +50 %, with the discount rate and energy price increase rate being the most influential parameters.

Purpose Robust assessments are needed to identify the best circular economy (CE) approaches related to their contribution to achieving a CE by simultaneously considering the complexity of the three pillars of sustainability (environmental, economic, social). In this regard, the circular life cycle sustainability assessment (C-LCSA) framework was recently developed. This study aimed to demonstrate its applicability and capability of identifying trade-offs and interlinkages between the different dimensions using a case study of different CE approaches to carpet tiles. Methods C-LCSA integrates circularity and life cycle sustainability assessments (LCSA). Thus, this study applied the material circularity indicator (MCI) in parallel to life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (S-LCA). The last technique was applied as social hotspot assessment. Five CE approaches of carpet tiles produced in the US, including strategies like reducing the consumption of primary materials through recycled and bio-based feedstock or replacing carpet tiles for a longer overall service life, as well as recycling, were assessed and compared to their mainly linear counterpart. Results and discussion The study revealed that recycling carpet tiles containing recycled and bio-based materials at the end-of-life (EoL) resulted in the lowest global warming potential (8.47 kg CO2 eq.) and the highest circularity (MCI value of 0.76, with 1 indicating the maximum level of circularity) compared to the other scenarios. However, this scenario had a trade-off with a higher acidification potential (0.039 kg SO2 eq.) and higher costs (US$19.98) compared to the disposal scenario. On the other hand, the scenario using primary, non-bio-based materials in production and disposing of the carpet tiles at their EoL performed the worst in circularity (MCI value of 0.11) and implied high environmental impacts while being more cost-effective (US$10.27). Conclusions C-LCSA

Particleboard manufacturers face challenges with conventional adhesives and the shortage of wood particles. This research aims to offer an alternative to particleboard raw materials and investigates the physico-mechanical properties of particleboard made from sweet corn stalks (Zea mays L.) and citric acid (CA), with a focus on its suitability for furniture applications. The targeted density of particleboard was 0.7 g/cm3 and the CA solution addition was in the range of 0–25 wt%. The results show that the addition of 15 wt% CA increased the physico-mechanical properties of the panel. The physico-mechanical properties of particleboard with the addition of 25 wt% CA met the requirements of JIS A 5908 (2022). Py-GC/MS analysis of corn stalk particles shows 62 derivative compounds. The FTIR analysis confirms the formation of ester linkages between the carboxyl group of CA and hydroxyl groups of corn stalk.

Our planet faces mounting environmental burdens due to linear production and consumption. Circular economy strategies offer a promising alternative, but evaluating their effectiveness requires robust measurement tools. Existing approaches lack a comprehensive framework incorporating the hierarchical strategies proposed by the 9R framework and the butterfly diagram. Based on the current circular economy indicators, this study gathers a set of indicators designed to assess the efficacy of circular economy strategies, considering the hierarchical levels outlined in the 9R framework. Moreover, it leverages the Analytic Hierarchy Process (AHP) fundamental scale as an integration tool to consolidate the suggested indicators into a unified metric termed the “9R circularity index”. This approach relies on a bottom-up approach to measure circular economy at various levels. The “9R circularity index” enhances the ability to compare results from a material flow analysis perspective. In addition, this paper presents a step-by-step approach and a supporting software tool that aims to facilitate the measurement, selection and comparison between circular and linear models. Ultimately, this proposed approach offers a workable, data-driven tool to support the transition towards a circular economy.

The environmental effects associated with buildings are significant and include considerable contributions towards global greenhouse gas emissions, energy use, and waste generation. Until recently, mitigation efforts have concentrated on improving the operational energy efficiency of buildings, largely ignoring embodied environmental effects. However, focusing solely on increasing energy efficiency can inadvertently cause an rise in embodied effects. It is therefore critical that embodied effects are considered alongside operational effects and are actively integrated into design decisions throughout the building design process. Life cycle assessment (LCA) can be used to achieve this, however, it is often perceived as difficult to incorporate into design workflows, or requiring specialist knowledge. Additionally, it is not always clear how well aligned LCA approaches are with the building design process. To address this gap, this study aims to provide a detailed analysis of LCA approaches, to assess how well they align with building design stages, and to identify key characteristics, including LCA tools and environmental data used to conduct assessments. A review of academic and grey literature is conducted. Three primary approaches are identified for integrating LCA into the building design process: simplified, detailed and incremental LCA. Simplified LCA uses streamlined data inputs and typically targets a specific design stage. Detailed LCA follows a traditional approach with comprehensive user inputs and results. Incremental LCA progressively evolves the assessment based on design requirements and available building data at each design stage. An analysis of each approach is performed, and key user requirements are mapped against the early design, and detailed design stages. Results reveal that no single approach fully satisfies all design requirements. Findings also highlight a lack of incremental LCA approaches and challenges operationalising these techniques.

Robust monitoring and assessment methods are required to assess circular economy (CE) concepts in terms of their degree of circularity and their contribution to sustainability. This research aimed to develop an integrated framework for the CE context—considering both the technical circularity and the complexity of the three dimensions of sustainability (environment, economy, and social). Two existing methods were identified as an appropriate foundation: CE indicators and life cycle sustainability assessment (LCSA), combining life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (S‐LCA). The developed circular life cycle sustainability assessment (C‐LCSA) framework added circularity assessment (CA) as an additional dimension to LCSA (C‐LCSA = LCA + LCC + S‐LCA + CA). The abundance of CE indicators required a systematic selection process to identify the most appropriate indicators for the framework which was built on criteria levels, performance, loops, unit, dimension, and transversality. The material circularity indicator, product circularity indicator, and longevity indicator were identified as most suited for C‐LCSA. Being developed for a single life cycle, the traditional life cycle approaches needed refinements for application to CE concepts, derived from discussions and proposed adaptions presented in the academic literature. The cut‐off approach was identified as the most suitable end‐of‐life allocation method for C‐LCSA, being in line with the technical system boundaries. C‐LCSA can be used by LCA practitioners to identify trade‐offs between an improved circularity and resulting impacts on the environmental, economic, and social pillars to provide a basis for decision making in industrial ecology.

The literature on the evaluation of environmental performance within the circular economy (CE) domain is notably extensive, encompassing a considerable body of work spanning guidelines, case studies and software tools. Nonetheless, a comprehensive overview that encompasses the entirety of the knowledge landscape in this area remains notably absent. To address this scholarly gap, the present study undertakes a scoping review. Departing from previous inquiries which have predominantly focused on scholarly literature, the study amalgamates diverse knowledge sources. Through a meticulously orchestrated search and analysis process that integrates insights from academic databases and other knowledge reservoirs in the Australian context, a compendium of 249 indicators is delineated. As one of the pioneering endeavours of this nature, this study functions as a contemporary reference, catering to researchers, policy makers and practitioners, while providing multifaceted perspectives on assessing environmental ramifications within CE research. In theoretical terms, this investigation makes an in-depth contribution to the CE field by introducing a methodical and all-encompassing framework, interlinking life cycle phases and system boundaries for environmental evaluation within the CE paradigm. The findings furnish a reliable catalogue of 12 pivotal themes that merit prioritisation in the evaluation of environmental impacts tied to CE strategies. On a practical level, the study yields valuable instruments for researchers, practitioners and policy makers, equipping them with the means to gauge the efficacy of their CE endeavours, thereby facilitating data-driven decision-making processes.

To counter the high consumption of resources and environmental emissions in the construction sector, innovative materials such as carbon-reinforced concrete (CRC) are needed. CRC has the potential to lower the resource use and emissions of the construction sector and lead to a circular economy (CE). To understand the overall circularity and sustainability performance of such materials, holistic assessments are needed. This study demonstrated the application of the newly developed circular life cycle sustainability assessment (C-LCSA) framework that is based on CE indicators and life cycle sustainability assessment (LCSA). The framework was applied to an industrial floor that was made from recycled CRC scrap (R–CRC industrial floor) in its development phase – using both the concrete faction and the carbon fiber fraction. The material circularity indicator (MCI) was used for the circularity assessment. It was applied in parallel to a life cycle assessment (LCA), life cycle costing (LCC), and a social hotspot assessment, using the same functional unit and system boundaries. The cut-off approach used was in line with the technical system boundaries. The results showed that the contribution to the circularity of the R–CRC industrial floor was high (0.8184) due to the use of recycled material and the potential of being recycled again. The global warming potential (GWP, 167 kg CO2 eq.) was lower while the human toxicity potential (HTP) was higher compared to similar products. The production costs far exceeded the current price of a comparable product which might be related to the inefficiencies in the production at the laboratory scale in the development phase of the R–CRC industrial floor. Social risks were found for health and safety, as well as for the social acceptance of the floor due to technical uncertainties. Increasing the circularity further by only using recycled aggregates mostly showed positive effects on the environmental impacts. However, HTP and costs incre

As global urbanisation levels continue to rise, supplying urban areas with low emissions energy becomes imperative in the fight against climate change. In areas with high demand density, district heating and cooling systems are generally a more efficient alternative compared to individual solutions, but current systems are mainly powered by fossil fuels and suffer from significant thermal losses due to high operating temperatures. Fifth-generation district heating and cooling systems (5GDHC) is a promising technology, able to address these drawbacks. 5GDHC systems operate at near ambient temperature, ensuring efficient integration of renewable energy sources and waste heat recovery potential. Their ability to provide simultaneous heating and cooling through the same pipeline and bidirectional energy flows allow for load balancing through the harvesting of demand synergies between different users. 5GDHC systems can play an important role in the energy transition but not much is known about their environmental performance over their life cycle and the novelty of the concept means that planning and design guidelines are scarcely present in the literature, hindering their development and further adoption. This study critically reviews recent advancements in the relevant literature as the 5GDHC technology transitions from research and development to the demonstration phase. Moreover, the paper addresses the design parameters and methodologies encountered in the literature for the modelling and operation of 5GDHC systems. Finally, the economic and environmental performance are discussed while presenting an overview of future developments and challenges related to full-scale deployment.

Urgent changes are needed in the construction industry to address the adverse effects of material production on the environment. The construction of tall buildings results in a high temporal and spatial concentration of greenhouse gas (GHG) emissions. This is largely due to the compounding influence of wind and earthquake loads on structural material requirements. Thus, to meet short-term climate change mitigation goals, the structural design of tall buildings must consider and minimise the embodied GHG emissions of structural systems. This study aimed to develop a framework to inform the design of tall building structural systems in order to minimise their embodied GHG emissions. A software tool was developed to implement the framework and automate the design, analysis, and embodied GHG emissions assessment of structural systems for tall buildings. Approximately 1,000 building models were iteratively designed, analysed, and assessed using the software tool. Through regression analyses, the resulting dataset was used to construct predictive models for the embodied GHG emissions of 12 unique combinations of structural system typologies and materials. By applying the framework and software tool to a 52-storey case study building, it is estimated that optimising structural material choices and geometric design strategies could reduce the embodied GHG emissions of tall building structural systems by up to 20% compared to current practices. The developed framework and software tool allow designers to use environmental assessment as a design decision-making tool, rather than an appraisal method for evaluating completed buildings, helping to reduce the environmental effects associated with tall building construction.

A transition to a circular economy (CE) affects different stakeholders – positively and negatively. Social aspects still receive little consideration in the context of CE, which is why the assessment and monitoring of the social impacts of CE still require further development and consideration in research. In this context, social circularity indicators and social life cycle assessment (S-LCA) are important tools that were examined in more detail in this study. This paper aimed to assess the current state of social circularity indicators in the literature, the implementation of S-LCA to assess CE concepts, and which additional indicators might be included in future S-LCA studies. Focus will be on the methodological approach of how to assess the social impacts of CE. A systematic literature review was conducted using Scopus Database, Google Scholar, and Web of Science. The search terms were derived from the aim of the study to identify the social impacts of CE in existing literature, to compile relevant social indicators in the context of CE, and to analyze the current role of S-LCA in the assessment of CE concepts. 97 papers were found. After excluding contributions that did not match the search criteria and adding new relevant contributions found through the analysis of the identified studies with the snowball sampling approach, 40 papers were considered in the review. 40 social impacts of CE were found within the literature. About half of them were positive and the other half negative. The authors found that positive impacts for some stakeholders could imply negative consequences for others, e.g., job creation in one region might lead to a decline in job opportunities in other regions. To assess CE, 104 single social indicators and 9 composed indicators were identified. Most of them could be linked to stakeholder groups and subcategories proposed in the UNEP S-LCA guidelines (UNEP, 2020). Training and education, job creation, as well as health and safety were relev

The focus of this study is Ydalir, a neighbourhood in Norway currently in the early planning stages. Ydalir aims to produce its energy locally based on renewable sources, has passive house standards or higher for all its buildings, uses timber or other materials with low embodied greenhouse gas emissions (EGHGE) as its main building materials and prioritises low emissions solutions for the mobility of its inhabitants. Because of those characteristics, the EGHGE related to the operational phases at Ydalir will be low and the relative importance of the EGHGE related to the materials will increase. The EGHE at Ydalir should thus be quantified in a comprehensive manner. Hybrid life cycle assessment (hLCA), which combines process-based life cycle assessment (pLCA) with economic input-output (IO) data is well-suited for this task because a better system boundary completeness is achieved while maximizing the use of typically more reliable process data. Regionalized (Norway) hybrid EGHGE coefficients are compiled for all the main construction materials. The proportion of the IO data (10–78%, average of 34%, and median of 24%) demonstrates the signification truncation associated with traditional pLCA. The EGHGE related to the construction materials, the transport needed along the value chains and to the construction site, and the use of fossil fuels along the value chains (in particular coal) is significant and must be addressed as part of a holistic approach to reducing the EGHGE of our buildings and neighbourhoods, in- and out-land.

Cities are complex sociotechnical systems, of which buildings and infrastructure assets (built stocks) constitute a critical part. As the main global users of primary energy and emitters of associated greenhouse gases, there is a need for the introduction of measures capable of enhancing the environmental performance of built stocks in cities and mitigating negative externalities such as pollution and greenhouse gas emissions. To date, most environmental modeling and assessment approaches are often fragmented across disciplines and limited in scope, failing to provide a comprehensive evaluation. These approaches tend to focus either on one scale relevant to a discipline (e.g., buildings, roads, parks) or particular environmental flows (e.g., energy, greenhouse emissions). Here, we present a framework aimed at overcoming many of these limitations. By combining life cycle assessment and dynamic modeling using a nested systems theory, this framework provides a more holistic and integrated approach for modeling and improving the environmental performance of built stocks and their occupants, including material stocks and flows, embodied, operational, and mobility-related environmental flows, as well as cost, and carbon sequestration in materials and green infrastructure. This comprehensive approach enables a very detailed parametrization that supports testing different policy scenarios at a material, element, building, and neighborhood level, and across different environmental flows. We test parts of our modeling framework on a proof-of-concept case study neighborhood in Melbourne, Australia, demonstrating its breadth. The proposed modeling framework can enable an advanced assessment of built stocks that enhances our capacity to improve the life cycle environmental performance of cities.

The global construction industry is responsible for considerable effects on the environment and society. The construction and use of our built environment accounts for 39% of global greenhouse gas emissions. Population growth and rising standards of living are further exacerbating these problems. Understanding the contribution of construction industries and those activities responsible for the greatest share of greenhouse gas emissions is crucial in order to identify opportunities for emissions mitigation. This study uses multi-regional input-output analysis to analyse the embodied greenhouse gas emissions of global construction industries. A structural path analysis (SPA) was conducted for the construction sectors of 44 countries using top-down economic input-output data from EXIOBASE3. The findings were analysed to compare the embodied greenhouse gas emissions of each construction sector to ascertain their emissions intensity. The structural path analysis was used to disaggregate each sector into unique nodes or pathways, with each representing a single or group of activities and their associated emissions. This was used to identify critical hot spots of emissions within the various construction supply chains. The results show that there is wide discrepancy between the emissions intensity of the construction industry for the 44 countries, ranging from 0.165 kgCO2e/Euro to 2.05 kgCO2e/Euro. In addition, the most significant contributors to emissions for the most emissions intensive countries are the production of concrete and steel. This in-depth analysis of global construction industries using multi-regional input-output data provides critical information needed to identify opportunities for reducing global construction-related greenhouse gas emissions. This will help prioritise future emissions reduction efforts within the construction industry and target specific solutions to achieve the greatest improvements to the overall environmental performance of global co

Demand for new buildings and infrastructure continues to grow and will only increase in coming years to cater for forecast growth in global population. This demand will result in considerable strain on the natural environment, resulting from the operation of these new built assets as well as the demand for resources required to construct and maintain them. Life cycle assessment is a tool that can be used during the design or refurbishment of new or existing buildings or infrastructure projects, to assess and improve their environmental performance. A life cycle assessment is often time consuming and complex, especially when used for the analysis of entire construction projects. This is particularly true when it is used to analyse construction-related, or embodied, environmental flows (e.g. embodied greenhouse gas emissions). To simplify the process, especially with projects that have tight time or budget constraints, product-based environmental flow coefficients are often used, which provide an indication of the environmental flows associated with specific construction materials. However, existing coefficients are typically based on process data, inherent with truncated product system boundaries. This paper introduces the Environmental Performance in Construction (EPiC) Database, a comprehensive database of hybrid embodied environmental flow coefficients for construction materials in Australia. EPiC uses a hybrid life cycle inventory approach to fill the gaps that exist in process data and provide embodied environmental flow coefficients that are systemically complete. This study has shown that existing process data for materials is on average 55% incomplete, but considerable inconsistency in system boundary coverage means that this incompleteness varies from 2% to 99% across materials and environmental flows. Other key strengths of EPiC are its transparency, providing open access to all data, and methodological consistency, with coefficient data sources and methods

The building sector is a significant contributor to global energy demand and greenhouse gas emissions and thus has a major role in combating climate change. To date, efforts to address this issue have focussed on reducing energy demand during building operation, resulting in significant reductions in this area. However, recent studies have shown that substantial improvements to operational energy efficiency have increased the relative significance of indirect or embodied energy demands and associated greenhouse gas emissions. Subsequently, policies addressing this next frontier of energy and emissions reductions are emerging. To understand different approaches and inform future development, this study reviews existing policy mechanisms targeting embodied energy and greenhouse gas emissions in the building sector for four countries – Australia, Canada, USA and United Kingdom. The study found that voluntary instruments dominate the policy landscape, with regulatory measures largely absent at national levels and confined to inconsistent application across lower levels of governance. Signals of change emerging from the analysis include growing private sector investment and increasing quantitative targets for reduction. The study concludes with the challenges facing this sector of energy governance, alongside recommendations for regulated caps, mandatory LCA reporting, prerequisite requirements in voluntary instruments, data accessibility and resolving methodological inconsistencies.

The food service industry has seen the advent of online food delivery services (OFDS) due to the development of online retailing and a rise in mobile phone usage. OFDS are growing in popularity around the world and are increasing the use of take-away food packaging and the subsequent environmental implications from its production and disposal. While a large number of studies have considered packaging-related environmental effects, there has been limited focus on the effect of OFDS-related packaging demand on the environment, particularly in relation to greenhouse gas emissions. This study quantifies the packaging-related greenhouse gas emissions associated with OFDS orders. Data on food packaging for a range of the most popular cuisines delivered by OFDS in Australia were collected from restaurants. The assessment was performed using the Packaging Impact Quick Evaluation Tool, which showed that the packaging-related greenhouse gas emissions for a single order ranges from 0.15 to 0.29 kg CO2e, depending on packaging type. Of this, production of packaging raw materials contributes at least 50%. With the expansion of the OFDS sector, the annual greenhouse gas emissions associated with OFDS food packaging in Australia is predicted to grow by 132% by 2024. This preliminary examination of the greenhouse gas emissions implications of food packaging production and disposal associated with the Australian OFDS industry adds to the limited knowledge in this area and provides valuable insights into the greenhouse gas emissions implications of the emerging global OFDS industry.

The emergence and global spread of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) at the beginning of 2020 changed the way we live our lives, including how and where we undertook our everyday activities. Strict lockdown rules, put in place to limit the spread of the virus, saw activity centres, workplaces and schools deserted, and homes become places of work and education. This shift led to a reduction in energy demand for many businesses. However, much of this energy demand transferred to households with most householders occupying their houses for most of the day, leading to increased use of heating, cooling, lighting and appliances, such as computers. This study analyses the total energy usage data for a household in Melbourne, Australia to explore the possible effect of the COVID-19-related lockdown on the household’s energy demand. Energy usage data was sourced from energy bills and the electricity distributor. Data associated with the period where all householders were working and studying solely at home (March to June 2020) were compared to six years of historical energy usage data for the same time period. The analysis shows a 26% increase in household energy demand. This also hasimplications for household finances.

While considerable improvements to the energy efficiency of housing have been achieved over recent decades, the residential sector still represents a significant and increasing proportion of global greenhouse gas emissions. This is exacerbated by an increasing global population and living standards, demand for larger houses, and smaller household size. Tiny houses have emerged as a potential solution to this issue. While research exists on the environmental benefits of smaller housing, there is little on that of tiny houses. This study quantifies the life cycle GHG emissions of a tiny house, and their potential to reduce residential GHG emissions. A hybrid analysis and a dynamic energy modelling tool were used to quantify embodied and operational GHG emissions, respectively, for a tiny house located in Australia. The study shows that a tiny house may result in a 70% reduction in per capita GHG emissions over its life compared to a traditional Australian house. This indicates the potential of tiny houses to be a useful option for reducing GHG emissions in the building sector.

Australia is going through a significant housing boom with approximately 200,000 new homes built each year; and significantly more are required on an annual basis to accommodate the estimated population growth of almost 36 million by 2050. The effects of climate change are increasingly being felt and responsive action is required for mitigation and adaption, which must include the greenhouse gas (GHG) emission implications of this new residential stock. Mitigation strategies have been predominantly focused on decreasing the operational GHG emissions associated with buildings, leaving the other life cycle stages, such as construction, largely ignored. To achieve national targets, such as zero net emissions by 2050, it is imperative to address GHG emissions mitigation from a life cycle perspective. This study found that based on current building practices one new detached dwelling built today will be responsible for roughly 545 tCO2e by 2050. This translates to the need to plant over 8,000 trees to offset these emissions, a figure it is safe to say, most homeowners will not achieve. This study modelled life cycle GHG emissions of all new detached dwellings constructed in Australia for a single year (2019) estimating 39 MtCO2e, which increases to 883 MtCO2e by 2030 and 3,654 MtCO2e by 2050. This is much higher than the current projections for Australia's total emissions by 2030 of 563 MtCO2e if a business as usual approach is followed, and the optimum target of 441 MtCO2e to meet emissions targets of 26% less than 2005. The results of this study suggest that housing-related GHG emission are underestimated by 60%, because of the absence of embodied GHG emissions being counted in emission projections. This emphasises that firstly, target and current GHG emission projections fail to consider emissions from a life cycle perspective, and primarily report findings based on operational data, which as this study has shown can lead to a misrepresentation of almost 96% of total

While traditional value engineering (VE) is primarily driven by cost saving, this study aims to comprehensively and reliably investigating the impact of traditional VE on the embodied greenhouse gas (GHG) emissions in the Australian built environment. An Australian-specific hybrid life cycle assessment (LCA) is developed and applied to a mixed-use building complex located in central Sydney, Australia. A list of GHG emissions intensities (GEIs) for 118 construction products is derived from hybrid LCA, demonstrating an average increase of 20% than the corresponding process-based GEIs. By applying the hybrid GEIs, the assessment of the case study building proves that traditional VE can potentially provide environmental benefits through the dematerialisation of the building. These benefits are small in this instance, with a capital cost reduction of 0.72% equating to an embodied GHG reduction of 0.32%, or a total of −267 t CO2e (i.e. -3 kg CO2e/m2 gross floor area), but if such savings were rolled out across the entirety of new building stock in Australia, the accumulated GHG emissions reduction would be significant. Concrete, reinforcing steel and timber formwork are the hotspots for cost and embodied GHG emissions reduction. Manufacturing and electricity are the originating industries that jointly contribute to more than 80% of the embodied GHG emissions.

The construction industry is an important driver for economic growth, but it is also a major contributor to global energy use and greenhouse gas emissions. A plethora of sustainable design tools and rating schemes have been developed in an attempt to improve the environmental performance of buildings. Regardless of their increasing adoption by the construction industry, much of the existing focus is on improving the operational performance of buildings. However, a more holistic life cycle approach that also considers material production is critical. Despite this, limited information and tools are available that consider the full life cycle at the point where decisions can have the greatest impact – at the early stages of design. This paper presents a web-based tool to assist environmental decision-making by providing information on the life cycle energy loadings of building envelope assemblies at the early stages of design. Real-time embodied energy calculations are combined with cloud-based building energy simulation within a graphical user interface that enables exploration of different alternatives through interactive visualisations. This paper describes the tool, an output of over 10 years of research, and how it can be used to inform building envelope assembly selection to reduce life cycle energy.

Buildings contribute to greenhouse gas (GHG) emissions throughout their life—from material extraction and production to building demolition and disposal. Current GHG emission reduction efforts largely focus on building operation, typically ignoring embodied emissions. One of the main barriers affecting the uptake of embodied GHG emissions considerations is the uncertainty related to the economic value of a building with reduced life-cycle GHG emissions. A conceptual approach is presented for integrating the life-cycle GHG emissions of a building into an economic evaluation. A case study detached residential dwelling located in Melbourne, Australia, is used to demonstrate the approach using a range of economic valuation approaches. One approach, using a carbon tax, shows that the effective cost for a single household would be over A$2000 for the first year, rising to almost A$5000 in 10 years. Across the range of evaluation approaches considered, the total cost to the householder is found to be between A$4600 and A$7860. With the embodied GHG emissions accounting for over 66% of the case study’s life-cycle GHG emissions, the majority of the economic liability for the householder relates to the initial construction and ongoing material replacement of the building.

Responsible for significant energy demand and emissions, the building sector has an opportunity to contribute to global sustainability efforts. In creating resilient and sustainable human settlements, alternative design approaches that address life cycle energy requirements are needed. Design for Dematerialisation is one such approach that aims to lower life cycle energy requirements by reducing material and resource inputs. Yet, despite its conceptual simplicity, the application of the approach within the building sector and its effect on life cycle energy demand is poorly understood. This study seeks to briefly outline the approach from the perspective of the building sector and examine the effect of dematerialisation actions on the life cycle energy requirements of a multi-residential building in Melbourne, Australia. This study demonstrates that while an effect is observed – most notably in recurrent embodied energy – a partial rebound effect exists. Savings from the reduction of key materials and components are partially negated by the energy intensity of alternative materials introduced, and/or additional elements required to maintain the building’s fitness-for-purpose. The assessment highlights the need for designers to address energy performance holistically, by taking into account the effect of actions on multiple life cycle stages concurrently. By employing this considered approach, dematerialisation has the potential to be an accessible strategy for designers tasked with creating sustainable, resilient urban settlements.

The construction of tall buildings generates a high spatial and temporal concentration of greenhouse gas (GHG) emissions. Research has shown that as building height increases, more resources per floor area are required to withstand the increasing effects of wind and earthquake loads. This has major implications for the environmental performance of tall buildings since the embodied GHG emissions (EGHGE) of structural systems tend to represent the greatest portion of the life cycle GHG emissions of tall buildings. In mitigating the effects of climate change, life cycle assessment (LCA) has been proposed as an early stage design tool to facilitate the choice of structural systems for tall buildings. However, international standards on LCA do not specify which of the three main life cycle inventory (LCI) approaches to use - process analysis, environmentally-extended input-output analysis or hybrid analysis. The aim of this paper is to evaluate the influence of LCI approaches on the choice of structural systems for tall buildings to minimise their embodied GHG emissions. The effects of LCI approaches on the choice of structural systems for tall buildings are evaluated using 10 tall buildings, ranging in height from 10 to 50 storeys, parametrically designed using finite element modelling. Two alternative structural systems are proposed and various LCI approaches are used to compare their EGHGE. The paper demonstrates that varying the LCI approach can significantly influence the values of EGHGE of structural systems for tall buildings by up to 116%. Notably, the paper demonstrates that, in minimising EGHGE, the adopted LCI approach can influence the choice of structural systems for tall buildings. The findings of this study confirm the need for clarity, transparency and comprehensiveness in the use of LCI approaches for comparative LCA studies, particularly in the structural design of tall buildings.

The construction of tall buildings generates a high spatial and temporal concentration of greenhouse gas (GHG) emissions. Research has shown that as building height increases, more resources per floor area are required to withstand the increasing effects of wind and earthquake loads. This has major implications for the environmental performance of tall buildings since the embodied GHG emissions (EGHGE) of structural systems tend to represent the greatest portion of the life cycle EGHGE of tall buildings. In mitigating the effects of climate change, life cycle assessment (LCA) has been proposed as an early stage design tool to facilitate the choice of structural systems and materials for tall buildings. Existing studies that use LCA to compare alternative structural systems and materials use incomplete and inconsistent structural design methods related to imposed loads, façade loads and lateral loads, both static and dynamic in nature. The aim of this paper is to demonstrate the influence of these structural design methods on the EGHGE of structural systems for tall buildings. The influence of structural design methods on the EGHGE of structural systems for tall buildings are evaluated using a total of 80 structural systems, parametrically designed using finite element modelling. A hybrid life cycle inventory analysis method is used to quantify the EGHGE of the structural systems. The paper demonstrates that structural design methods can significantly influence the values of EGHGE of structural systems for tall buildings, by up to 22%. The findings of this study confirm the need for clarity, consistency, transparency and comprehensiveness in structural design methods when conducting comparative LCA studies of structural systems for tall buildings.

Buildings account for at least one third of global greenhouse gas emissions and existing buildings constitute 98 per cent of Australia’s building stock in any one year. Hence, existing buildings, many of which have high cultural heritage value, play an important role in addressing climate change and other key environmental challenges. Despite convincing evidence that historic buildings are high environmental performers, most environmental improvement initiatives within building and planning systems continue to focus heavily on operational performance. They generally fail to value broader indicators of environmental sustainability such as resource depletion, material waste and pollution. When these broader environmental benefits of maintaining existing buildings are not considered or appropriately valued, historic fabric is often removed or demolished, often replaced by newer ‘green’ buildings. This not only results in the loss of important cultural heritage, but also a substantial opportunity for maximising environmental outcomes. This article reviews national and international literature on environmental and cultural sustainability to highlight the broad environmental benefits of conserving historic buildings; how they can be valued; and what further research is required to ensure building and planning systems adequately address the role that buildings play within the challenge of anthropogenic climate change.

As worldwide consumption of materials continues to rise, there is growing pressure on material, energy and water resources and an increase in waste production and greenhouse gas emissions. A much more sustainable approach to the procurement of built assets is crucial to avoid exacerbating existing environmental pressures. Product and process-based environmental data is an important element in understanding how current and future built assets perform. This paper analyses environmental flow data for a range of construction materials contained within the Environmental Performance in Construction (EPiC) Database, a new, open access repository of hybrid environmental flow coefficients for construction materials. The structural paths of 131 construction materials are analysed to identify trends and contributors to embodied water, energy and greenhouse gas (GHG) emissions coefficients. The disaggregation and analysis of material coefficients shows the complexity of the material supply chains and provides insight into the key inputs and outputs resulting from the production of construction materials.

Life cycle assessment is increasingly used to quantify and reduce the environmental effects of buildings. Embodied environmental effects, resulting from material production and replacement as well as construction, are typically quantified using coefficients from readily available databases. However, most existing databases of embodied environmental coefficients for construction materials suffer from limitations, such as inconsistency in the life cycle inventory method used or system boundary incompleteness. This paper introduces a new database of hybrid environmental flow coefficients for construction materials, covering flows of energy, water and greenhouse gas emissions for over 100 common construction materials. The hybrid approach used combines bottom-up industrial process data and top-down macroeconomic input-output data, making it more comprehensive than process analysis and more accurate and specific than input-output analysis alone. A case study building is used to demonstrate the importance of using hybrid coefficients for improving environmental performance. This study shows that the use of process coefficients can lead to a significant underestimation of the total environmental effects associated with the construction of a building, by up to 64%. This has considerable implications for decision-making relating to building design, including the focus of improvement efforts. This database of coefficients will enable building professionals to more effectively analyse and improve the environmental performance of buildings. This will also help inform the focus of environmental policy and improve the implementation of life cycle thinking in environmental design.

The EPiC Database contains environmental flow coefficients for over 250 common construction materials and products. Developed using complete, transparent and consistent methods, the EPiC coefficients can be used to assess the embodied energy, water and greenhouse gas emissions of construction projects, assisting with design, construction and whole of life decision-making. The EPiC database is the result of a four-year multi-institutional research project, led by internationally recognised experts in modelling embodied environmental flows. Their combined 30+ years of experience in the field is testimony to their commitment to improving the environmental performance of construction.

The Low Energy Building Assembly Selector was developed in collaboration between The University of Melbourne and Williams Boag Architects and supported by the Australian Research Council under project LP120200306. The tool provides a means for building designers and other construction industry professionals to make informed decisions regarding the selection of construction assemblies for optimising a building’s life cycle energy demand.

During the 1960s, the Bangladeshi-American structural engineer and architect Fazlur Rahman Khan proposed an influential design framework for the structural systems of tall buildings titled premium-for-height. Khan argued that the challenge of a structural engineer is to design structural systems that minimise the increase in structural material weight per gross floor area with increasing building height. However, in meeting the challenges of climate change and urbanisation, minimising the embodied environmental flows of tall buildings must also be a priority in structural design frameworks. This paper proposes to expand the premium-for-height framework for tall buildings by considering the embodied greenhouse gas emissions of structural systems using a hybrid life cycle inventory analysis method. Advanced structural analysis and a comprehensive consideration of building parameters are also proposed. To demonstrate the use and potential of the framework, embodied greenhouse gas emissions of six case study tall buildings are analysed. The results arediscussed and recommendations are made to improve the reliability of the more comprehensive framework.

Purpose: Life cycle assessment (LCA) is inherently complex and time consuming. atypically involves the collection of data for dozens to hundreds of individual processes. More comprehensive LCI methods, such as input-output analysis and hybrid analysis can include data for billions of individual transactions or transactions/processes, respectively. While these two methods are known to provide a much more comprehensive overview of a product’s supply chain and related environmental flows, they further compound the complex and time-consuming nature of an LCA. This has limited the uptake of more comprehensive LCI methods, potentially leading to ill-informed environmental decision-making. A more accessible approach for compiling a hybrid LCI is needed to facilitate its wider use. Methods: This study develops a model for streamlining a hybrid LCI by automating various components of the approach. The model is based on the path exchange hybrid analysis method and includes a series of inter-related modules developed using object-oriented programming in Python. Individual modules have been developed for each task involved in compiling a hybrid LCI, including data processing, structural path analysis and path exchange or hybridisation. Results and discussion: The production of plasterboard is used as a case study to demonstrate the application of the automated hybrid model. Australian process and input-output data are used to determine a hybrid embodied greenhouse gas emissions value. Full automation of the node correspondence process, where nodes relating to identical processes across process and input-output data are identified, remains a challenge. This is due to varied dataset coverage, different levels of disaggregation between data sources and lack of detail of activities and coverage for specific processes. However, by automating other aspects of the compilation of a hybrid LCI, the comprehensive supply chain coverage afforded by hybrid analysis is able to be made more a

This chapter aims to increase awareness related to the assessment of embodied greenhouse gas emissions (GHGE) of the built environment in Australia—a critical step to achieve meaningful emissions reduction. A summary of existing methods, data, tools, guidance and gaps in quantifying embodied GHGE in the Australian built environment is provided. A quick evaluation of embodied GHGE is an important aid for the design decision-making process within the architecture, engineering and construction industries. The newly developed Embodied Carbon Explorer (ECE) online tool is introduced to rapidly assess embodied GHGE for built environment projects with National Carbon Offset Standard-performance objectives. A case study using the ECE tool is described that quantifies the total carbon footprint of Australia’s construction industry and identifies the main contributors of embodied GHGE.

A variety of methods can be used to compile a life cycle inventory (LCI) as part of a life cycle assessment (LCA) study. Hybrid LCI methods attempt to address the limitations inherent in more traditional process and input-output (IO) LCI methods. This paper provides an overview of the different hybrid LCI methods currently in use in an attempt to provide greater clarity around how each method is applied and their specific strengths and weaknesses. A search of publications quoting the use of hybrid LCI was undertaken for the period from 2010 to 2015, identifying 97 peer-reviewed publications referencing the use of a hybrid LCI. In over one third of the literature analysed, authors only refer to their analysis as a hybrid LCI, without naming the actual method used, making it difficult to fully understand which method was used and any potential limitations. Based on the way in which the various hybrid methods are applied and their existing use, the authors propose a set of clear definitions for existing hybrid LCI methods. This assists in creating a better understanding of, and confidence in, applying hybrid LCI methods amongst LCA practitioners, potentially leading to a greater uptake of hybrid LCI.

As global population and urbanization increase, so do the direct and indirect environmental impacts of construction around the world. Low-impact products, buildings, precincts and cities are needed to mitigate the effects of building construction and use. Analysis of embodied energy and greenhouse gas (GHG) emissions across these scales is becoming more important to support this direction. The calculation of embodied impacts requires rigorous, flexible and comprehensive assessment tools. Firstly, we present the Australian Industrial Ecology Virtual Laboratory (IELab) as one such tool discussing its structure, function and wide scope of application. Secondly, we demonstrate its potential high level of resolution in a case study: assessing embodied GHG emissions in an aluminium-framed window by combining product-specific life-cycle inventory data. The input-output analysis at the core of the IELab is mathematically comprehensive in the assessment of direct and indirect impacts and the tool can be applied at a range of scales from building component, to precincts and cities, or to the entire construction industry. IELab uses a flexible formalism that enables consistent harmonisation of diverse datasets and tractable updating of input data. The emissions and energy database supporting IELab has detailed data, aligning with economic accounts and data on labour, water, materials and waste that enrich assessment across other dimensions of sustainability. IELab is a comprehensive, flexible and robust assessment tool well positioned to respond to the challenge of assessing and aiding the design of a low-impact built environment.

In the framework of pressing local and global environmental challenges it is essential to understand that cities are complex systems dependent on and linked to the rest of the world through global supply chains that embody an array of environmental flows. Cities are thus a complex articulation that intertwine local and global challenges which rely at their extended hinterland for their resource use and pollution emission. To assess the environmental sustainability of an urban area in a comprehensive manner, it is not only necessary to measure its local and direct environmental performance but also to understand and take into account its global and indirect environmental counterparts. This paper presents a comparative analysis of a territorial-based and a consumption-based approach to estimate both direct and embodied resource use and pollution flows for the case of Brussels Capital Region (Belgium). The territorial-based approach is based on local energy, water and material consumption measured data as well as measured data on waste generation and pollution emissions. The estimation of indirect resource use and pollution emissions (or consumption-based approach) is based on the regional IO-tables of the city-region of Brussels extended with multi-region input-output tables, taking into account the global flows of consumption. The comparison of these two approaches is particularly relevant in the case of cities that have limited productive activities and limited or no extraction of materials as the impact on the hinterland is often underestimated or neglected by local (environmental) policies which are only based on territorial-based figures. The results show that the indirect primary energy use, GHG emissions and material use estimated by the consumption-based approach is more than three times higher than local measures indicate. The embodied water use, estimated via IOA, was over 40 times higher than the local water consumption. These results show that territorial

While relocatable, prefabricated learning environments have formed an important component of school infrastructure in Australia, prefabrication for permanent school buildings is a new and emerging field. This review of prefabrication for schools is timely. In 2017, Australia’s two largest state education departments committed to prefabrication programs for permanent school infrastructure. In this paper we examine the recent history of prefabrication for Australian school buildings in the context of prefabrication internationally. We explore the range of prefabrication methods used locally and internationally and introduce evaluation indicators for school infrastructure. Traditional post-occupancy evaluation (POE) tools measure indicators such as indoor environment quality (IEQ), cost benefit, life cycle performance, and speed of delivery. In response to a shift towards more student-centred learning in a digitally rich environment, recently developed POE tools now investigate the ability of new generation learning environments (NGLEs) to support optimum pedagogical encounters. We conclude with an argument for departments of education to consider how prefabrication provides opportunities for step changes in the delivery, life-cycle management and occupation of smart green schools rather than a program of simply building new schools quicker, better, and cheaper.

Environmental sustainability is a critical global challenge. Housing and infrastructure demand huge quantities of resources and result in significant environmental effects. The creation of ‘smart villages’ offers a unique opportunity to redefine how housing and infrastructure systems interact with the natural environment and explore solutions for improving their environmental sustainability. The concept of the Smart Village has a heavy focus on using technological solutions to enhance the existing networks and services available within a village community. This inevitably leads to an increase in resource use (both for construction and operation) which can be counterproductive to improving the environmental sustainability of villages. With environmental concerns becoming increasingly integral to decision-making, the design and implementation of Smart Villages must consider the potential environmental implications and performance of Smart Village solutions if they are to be considered truly ‘smart’. This paper introduces a four-step process for identifying, analysing and implementing solutions for achieving an environmentally sustainable Smart Village. This involves an integrated design process where the current environmental performance of a village is assessed (step 1), the local context is analysed to determine what resources, skills and expertise are locally available (step 2), potential Smart Village solutions are identified and analysed (step 3), and the Smart Village is designed and implemented, with the assistance of trained professionals and village communities (step 4). A village community located in Assam, India is used as a case study to demonstrate the application of step 1. By using this process in the design and implementation of Smart Villages, greater confidence is able to be placed in ensuring that potential solutions, both technological and non- technological are not creating greater environmental issues than already exist within villages. It can al