RP2007: Integrated Carbon Metrics – A Multi-Scale Life Cycle Approach to Assessing, Mapping and Tracking Carbon Outcomes for the Built Environment

RP2007: Journal Article: Global warming impact of suburbanisation: the case of Sydney

Suburbs have naturally become a focal point of carbon mitigation for cities undergoing rapid suburbanisation. This has created a debate over which urban form can more effectively lead to lower household carbon footprints (CF). Previous suburban-scale studies using economic input-output life cycle assessment with national average carbon intensities have demonstrated the mitigation potentials in households via urban planning. However, there is a need for suburban-scale multiregional input-output (MRIO) tables to model suburb-specific carbon intensities and thus to account for the heterogeneity of both production and consumption in different suburbs.
This study explores the case of Sydney, Australia, and its many suburbs.

The CF of households is broken down into 111 sectors and 248 spatial divisions of Greater Sydney by employing a suburban-scale MRIO model. The impact of domestic and overseas migration on household CFs is modelled during 2009–2010, and the CFs are allocated to different ethnic groups. The results suggest that residents in the densely populated city core have a comparable CF to residents living in outer city suburbs, thus contradicting previous studies supporting the notion that densely populated inner-city areas yield relatively lower CFs. The rapid growth of population increases household CFs in inner western suburbs. According to the study findings, the ongoing Sydney metropolitan development plan may therefore not be sufficient to provide a sustainable carbon emissions reduction strategy, if suburb density is increased without any constraints on resident consumption patterns. Urban planners need to consider policies to direct the investment brought by immigration towards a lower-carbon economy and infrastructure and also may take advantage of the sharing economy to change consumption behaviour.

Read the full article here: https://doi.org/10.1016/j.jclepro.2017.10.161

RP2007: Journal Article: City carbon footprint networks

Progressive cities worldwide have demonstrated political leadership by initiating meaningful strategies and actions to tackle climate change. However, the lack of knowledge concerning embodied greenhouse gas (GHG) emissions of cities has hampered effective mitigation. The authors analyse trans-boundary GHG emission transfers between five Australian cities and their trading partners, with embodied emission flows broken down into major economic sectors. The authors examine intercity carbon footprint (CF) networks and disclose a hierarchy of responsibility for emissions between cities and regions. Allocations of emissions to households, businesses and government and the carbon efficiency of expenditure have been analysed to inform mitigation policies.

The findings indicate that final demand in the five largest cities in Australia accounts for more than half of the nation’s CF. City households are responsible for about two thirds of the cities’ CFs; the rest can be attributed to government and business consumption and investment. The city network flows highlight that over half of emissions embodied in imports (EEI) to the five cities occur overseas. However, a hierarchy of GHG emissions reveals that overseas regions also outsource emissions to Australian cities such as Perth. The authors finally discuss the implications of their findings on carbon neutrality, low-carbon city concepts and strategies and allocation of subnational GHG responsibility.

Read the full article here: http://dx.doi.org/10.3390/en9080602

RP2007: Journal Article: Cost and embodied carbon reductions in cutter soil mix walls through fibre reinforcement

Cutter soil mix (CSM) walls are created by mixing soils with cement and bentonite slurry to produce a soil–cement mix with modest tensile and compressive strengths. CSM walls may be stabilised using internal steel beams. Presented here are the results of a CSM wall field trial and laboratory testing programme. Polypropylene fibres were added to the soil–cement mix in order to explore whether or not fibres increase wall resistance to bending, reduce the required quantity of steel and thus reduce cost and embodied carbon.

The trial involved mixing fibres into a single CSM wall panel. Samples were taken and tested at 28 days and 2 years to assess unconfined compressive strengths, indirect tensile strengths and flexural tensile strengths. The fibre orientation distribution was also assessed. The testing confirmed that the mixing technique resulted in a uniform orientation distribution of fibres and significantly improved tensile strength. Also presented is a hypothetical design of a fibre-reinforced CSM wall supporting an 8 m excavation to show that the steel quantity can be reduced while maintaining stability. A cost analysis, limited to the steel beams, fibres and anchors, shows that a CSM wall with 0.5% fibres by dry weight has a cost of $2930 AUD per linear metre of wall. This is significantly lower than the cost when no fibres were included, which is $4070 AUD per linear metre. The embodied carbon analysis, limited to the steel beams, fibres, cement and anchors, is also presented.

The analysis shows that a CSM wall with 0.5% fibres by dry weight produces an emissions saving (having a total of 755 kgCO2e/m3) compared to the CSM wall without fibres (having a total of 929 kgCO2e/m3). Increasing the fibre content from 0.5% does not significantly alter the cost or embodied carbon when the cement content is constant. However, a higher fibre content does have the potential to reduce embodied carbon and cost further if an adequate tensile strength can be achieved with a lower cement content.

Read the full article here: http://dx.doi.org/10.1680/jgein.17.00001

RP2007: Journal Article: The Australian industrial ecology virtual laboratory and multi-scale assessment of buildings and construction

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, the authors present the Australian Industrial Ecology Virtual Laboratory (IELab) as one such tool discussing its structure, function and wide scope of application. Secondly, the authors 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.

Read the full article here: http://dx.doi.org/10.1016/j.enbuild.2017.12.056 

RP2007: Journal Article: Transnational city carbon footprint networks – exploring carbon links between Australian and Chinese cities

Cities are leading actions against climate change through global networks. More than 360 global cities announced during the 2015 Paris Climate Conference that the collective impact of their commitments will deliver over half of the world’s urban greenhouse gas emissions reductions by 2020. Previous studies on multi-city carbon footprint networks using sub-national, multi-region input-output (MRIO) modelling have identified additional opportunities for addressing the negative impacts of climate change through joint actions between cities within a country. However, similar links between city carbon footprints have not yet been studied across countries.

In this study the authors focus on inter-city and inter-country carbon flows between two trading partners in a first attempt to address this gap. The authors construct a multi-scale, global MRIO model to describe a transnational city carbon footprint network among five Chinese megacities and the five largest Australian capital cities. First, the authors quantify city carbon footprints by sectors and regions. Based on the carbon map concept the authors show how local emissions reductions influence other regions’ carbon footprints. The authors then present a city emissions ’outsourcing hierarchy’ based on the balance of emissions embodied in intercity and international trade. The differences between cities and their position in the hierarchy emphasize the need for a bespoke treatment of their responsibilities towards climate change mitigation. Finally, the authors evaluate and discuss the potentially significant benefits of harmonising and aligning China’s carbon trading schemes with Australia’s cap and trade policy.

Read the full article here: http://dx.doi.org/10.1016/j.apenergy.2016.08.053

RP2007 Journal article: Carbon assessment for urban precincts: Integrated model and case studies

The building sector is the largest contributor to global greenhouse gas (GHG) emissions. Over the years, sound tools have been developed to support the life-cycle assessment of building carbon emissions performance. However, most of these tools have been primarily focused on building-scale modelling and evaluation, leaving the emissions related to infrastructure and occupant activities as well as the carbon offsetting from implementing district-scale renewable energy systems, often neglected. The uptake of macro perspective carbon evaluations at the urban precinct level has been slow due to various barriers such as system boundary definition, quantification of complex inter-building effects, availability of comparable data, integrated modelling and uncertainties related to occupants’ life styles. This research developed an integrated life-cycle model to support the precinct-scale evaluation of carbon footprint for a comprehensive understanding of the emission profile. This is expected to further support low carbon planning and (re)development of urban precincts. The model structure is underpinned by four major components at the precinct level, i.e. embodied, operational and travelling associated carbon emissions, as well as the carbon offsetting from solar energyharvesting. The utility of the proposed methodology is demonstrated through preliminary case studies on representative suburban precincts in Adelaide, South Australia. Comparative studies and scenario analysis are also involved to identify the critical elements affecting the overall carbon performance of urban precincts.

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RP2007: Journal article: Towards an Integrated Approach for Evaluating both the Life Cycle Environmental and Financial Performance of a Building: A Review

A building is responsible for the emission of a significant amount of greenhouse gas (GHG) emissions over the various stages of its life cycle. Industry and government have been primarily focused on assessing and implementing mitigation measures related to the operational GHG emissions of buildings, leaving the emissions related to other life cycle stages, such as raw material extraction and maintenance, largely ignored. However, the uptake of assessments, such as life cycle assessment (LCA), and mitigation measures that consider buildings’ emissions from a life cycle perspective has been slow due to various barriers.

One such barrier that has not been as widely documented yet is the uncertainty towards the financial cost of life cycle GHG emission reduction. There has been an increase in studies that have included both the environmental and financial assessment of a building or building systems over its expected lifetime.

These studies often use the economic methodology called life cycle costing (LCC), that complements the life cycle approach of LCA, to help quantify the financial impact of a project. However most of these studies either base their results on exemplary low energy buildings, not traditional buildings that dominate the built fabric.

In addition there is a trend to primarily focus on residential buildings, leaving other building typologies neglected. Other aspects to notice from these studies include the fact that most present findings of the life cycle energy impact, not life cycle GHG impact. There is also a need to use more comprehensive life cycle inventory data, such as hybrid, not just process data, to provide more comprehensive results. And lastly, most studies consider at new buildings, not refurbished or existing buildings.

LCA and LCC support each other from a life cycle perspective however there is still a need to further develop an approach to concurrently balance both economic and environmental performance to create a more sustainable built environment.

Read the paper HERE.

RP2007: Journal article: Integrated Carbon Metrics and Assessment for the Built Environment

One third of global greenhouse gas emissions are emitted from the building sector contributing significantly to the problem of climate change. While more work has been done on decreasing direct emissions from the operation of buildings, embodied emissions of construction materials receive little consideration even though they constitute a significant additional proportion of emissions.

The main objective of this study is to harmonise different data and methods such as Life Cycle Assessment (LCA), Input Output Analysis (IOA) and Material Flow Analysis (MFA) to accurately calculate the embodied carbon emissions of construction materials in Australia.

This study will develop and streamline efficient hybrid methodologies in analysing embodied emissions of the built environment at multiple scales and develop a comprehensive database of embodied carbon LCI data for building and construction materials that will be derived from an economy-wide modelling framework. 

Read the paper HERE.

RP2007: Journal article: Decomposition of integrated hybrid life cycle inventories by origin and final-stage inputs

This technical note presents a method to decompose life cycle inventories derived from integrated and mixed-unit hybrid life cycle assessment.

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RP2007: Journal Article: Mixed-unit hybrid life cycle assessment applied to the recycling of construction materials

teh s. h. wiedmann t. moore s. 2018 mixed unit hlca applied to the recycling of construction materials (2179691 PDF)

RP3007: PHD Study: Developing a framework for integrating life cycle environmental and economic assessment of buildings

phd schmidt monique 2018 developing a framework for lceea of buildings revised180426 (13373092 PDF)

RP2007: Journal article: A framework for the integrated optimisation of the life cycle greenhouse gas emissions and cost of buildings

Evaluating building design options with a focus on simultaneously minimising life cycle greenhouse gas emissions (GHG) and life cycle cost (LCC) is difficult due to a lack of comprehensive and accessible tools. An integrated approach where life cycle GHG and LCC performance can be balanced is essential in order to optimise a building's overall life cycle performance.

This paper describes the development of an integrated framework designed to assist building design professionals in optimising the life cycle GHG and cost of a building. This paper demonstrates the framework's potential by applying it to glazing design options for a residential building case study. The demonstration of this framework highlights the fact that options such as triple glazing, often heralded as a solution for reducing GHG, may not lead to as great a reduction in life cycle GHG as options such as double glazing (which also comes at a lower LCC for this case study building).

This paper not only highlights the need to analyse and select building design options based on both their life cycle GHG and LCC performance but also emphasises the significant amount of uncertainty attached to decision-making in these areas.

Read the paper HERE.

RP 2007: Journal article: Carbon assessment for urban precincts: Integrated model and case studies

This paper published in Energy and Buildings presents a model for the integrated assessment of precinct carbon performance which takes into account carbon offsetting as well as interplays among precinct objects, precinct morphology, and resident life-styles.

Carbon assessment for urban precincts: Integrated model and case studies (4833367 PDF)

RP2007: Journal article: Replacement scenarios for construction materials based on economy-wide hybrid LCA

By comparing residential and non-residential building stock scenarios using an IO-based hybrid LCA scenario method, this study gains insight into potential emissions reductions opportunities. The best-case emissions scenario would require all new building stock (both residential and non-residential) to be constructed from a timber structural design (timber scenario), with the worst-case emissions scenario being when new building stock is constructed from conventional reinforced concrete design (BAU scenario). If 100% of new residential building structures were to be constructed from EWPs instead of 100% reinforced concrete, a saving of 26 Mt CO2e can be achieved by 2050.

Read the article HERE.

Journal article: Towards an integrated approach for evaluating both the life cycle environmental and financial performance of a building

This study published in Science Direct highlights the importance of considering a buildings’ expected performance, whether it be environmental or financial, based on its entire life cycle.

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RP2007 Journal article: Life-cycle energy modelling for urban precinct systems

This paper published in the Journal of Cleaner Production  presents an approach for the evaluation of energy performance of urban precincts and includes the interactions among precinct objects, natural environment and occupant behaviours. The research has provided a model, supported by a case study of a typical outer Australian suburb, for exploring the life cycle energy consumption of urban precincts. 

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RP2007: Journal article: Hybrid life cycle assessment of greenhouse gas emissions from cement, concrete and geopolymer concrete in Australia

Teh, S. H., Wiedmann, T., Castel, A.,  de Burgh, J., Hybrid life cycle assessment of greenhouse gas emissions from cement, concrete and geopolymer concrete in Australia. Journal of Cleaner Production.

Concrete is the second most used material after water and the production of cement is responsible for 5–8% of global carbon dioxide emissions. The development of low-carbon concretes is pursued worldwide to help the construction industry make its contribution to decarbonising the built environment and achieving carbon reduction targets agreed under the Paris Climate Agreement. However, there is uncertainty around the actual amount of greenhouse gas emissions that can be avoided by employing alternative types of concrete. This study quantifies the carbon footprint intensities of Australian cement and concrete production, including ordinary Portland cement, standard ordinary Portland cement concrete, blended cement-based concrete and geopolymer concrete production. For the first time, an input-output based hybrid life-cycle assessment method is used for these products. The main goal of this paper is therefore to make a methodological comparison between process-based and hybrid life cycle assessment using the Australian cement and concrete production as a case study. A comparison with published results from process-based life-cycle inventories as well as a decomposition of results into product categories is provided. The hybrid life cycle assessment resulted in higher greenhouse gas emissions for ordinary Portland cement and all types of concrete due to the methodology incorporating an economy-wide system boundary, which includes the emissions from upstream processes. For geopolymer concrete in particular, the results were also dependent on the method applied for allocating greenhouse gas emissions from fly ash and slag. The findings from this study are likely to inform the development of strategies and policies aimed at greenhouse gas reduction in the cement and concrete industries.

Read the article here.

RP2007 Journal article: The Australian construction industry’s approach to embodied carbon assessment: a scoping study, Living and Learning: Research for a Better Built Environment

Fouché, M. and Crawford, R.H. (2015) The Australian construction industry’s approach to embodied carbon assessment: a scoping study, Living and Learning: Research for a Better Built Environment, 49th International Conference of the Architectural Science Association, edited by Crawford, R.H. and Stephan, A., Melbourne, Australia, 2-4 December, 578-587.

The building sector is responsible for a significant proportion of a nation’s greenhouse gas emissions. In an attempt to mitigate these emissions, industry and government have been mainly focussed on reducing operational emissions associated with buildings, leaving the embodied emissions largely ignored. As operational emissions continue to decrease, embodied emissions will start to play a larger role in the life cycle emissions of the built environment. Several tools and datasets have been created internationally and locally within Australia that seek to quantify these embodied carbon emissions. However due to lack of information, it is unclear first of all how the Australian construction industry is currently approaching embodied carbon analysis and secondly what tools and databases are being used for this analysis. A survey was executed as part of the Integrated Carbon Metrics (ICM) Project that aimed to not only addresses this lack of information but to also inform the ICM project tool outputs. These tool outputs will seek to address these often ignored embodied emissions and aim to quantify the carbon fabric of Australia’s built environment.            

Read the article here (177798 PDF)

RP2007: Journal article: Urban carbon transformations: unravelling spatial and inter-sectoral linkages for key city industries based on multi-region input-output analysis

Chen, G., Hadjikakou, M. and Wiedmann, T. (2016) Urban carbon transformations: unravelling spatial and inter-sectoral linkages for key city industries based on multi-region input-output analysis. Journal of Cleaner Production. Published online 20 April 2016

With around 80% of global greenhouse gas emissions directly or indirectly attributed to cities, attempts to mitigate climate change impacts must seriously consider urban carbon transformations. Two challenges are currently constraining urban planning decisions around decarbonisation. Firstly, a lack of detailed knowledge about city-induced emissions occurring outside of the city boundary hampers the design of mitigation strategies that involves the city's ‘hinterland’. Secondly, the complexity of interconnections between industries and regions located upstream or downstream the supply chain of urban economic activity makes it difficult to implement specific, effective and efficient decarbonisation policies. In this study, a multi-scale, multi-region input–output model with nested regions at city, state, nation and world level is employed to study the carbon footprints and the inter-sectoral linkages in terms of embodied carbon emissions of the two largest metropolitan areas of Australia, Melbourne and Sydney. The results show that imported emissions make up more than 50% of the city carbon footprints, with most of them attributable to goods (excluding food) and services (excluding electricity). This highlights the importance of promoting mitigation measures both within and outside of the city. The energy, mining and agriculture sectors – usually located outside of city boundaries – all have significant carbon linkage multipliers associated with city demand, indicating the need of pursuing carbon mitigation measures in these sectors. The linkage analysis pinpoints to crucial sectors that need to be targeted in future investments towards urban decarbonisation to minimise emissions and to maximise positive economic effects for urban and regional economies. The study also provides an improved understanding of the differences and similarities between Australia's two main cities. It is envisaged that this type of analysis will become increasingly relevant to other cities as the spatial resolution of multi-region input–output databases continues to improve.

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RP2007 Journal Article: Energy and carbon performance evaluation for buildings and urban precincts: review and a new modelling concept

Huang, B., Xing, K. and Pullen S. (2015) Energy and carbon performance evaluation for buildings and urban precincts: review and a new modelling concept. Journal of Cleaner Production (published online 23 December 2015). 

With the accelerating pace of urbanisation around the world, the planning, development and operation of buildings and precincts have become increasingly important with respect to energy use and the associated carbon footprint of the modern built environment. Over recent decades, much effort, both in research and in practice, has been devoted to building construction and urban planning for the improvement of energy efficiency and greenhouse gas emissions. However, the accuracy of modelling and evaluation of energy and carbon performance for buildings and urban precincts remains limited, affected by inadequate energy intensity data and highly integrated building systems, as well as the complex interactions between buildings and the urban eco-system. This paper presents a critical review of current measures and models for representing and assessing life cycle energy as well as associated emissions profiles at both the building and the precinct levels. It also identifies influential factors and explores interactions among buildings, surrounding environment and user behaviours at the urban precinct level by taking a systems perspective. Based on such a review, this study maps out some key challenges for integrating energy and carbon metrics, and finally proposes a precinct-level system boundary definition and an integrated model following systems thinking. The proposed model can facilitate a critical thinking approach about the evaluations of global energy and emissions, and support the quantification of energy consumption and associated emissions for building precinct systems.

Read the article HERE.

RP2007 Journal Article: The Concept of City Carbon Maps: A Case Study of Melbourne, Australia. Journal of Industrial Ecology

Wiedmann, T. O., Chen, G. and Barrett, J. (2015) The Concept of City Carbon Maps: A Case Study of Melbourne, Australia. Journal of Industrial Ecology, (published online 12 October 2015). 

Cities are thought to be associated with most of humanity's consumption of natural resources and impacts on the environment. Cities not only constitute major centers of economic activity, knowledge, innovation, and governance—they are also said to be linked to approximately 70% to 80% of global carbon dioxide emissions. This makes cities primary agents of change in a resource- and carbon-constraint world. In order to set meaningful targets, design successful policies, and implement effective mitigation strategies, it is important that greenhouse gas (GHG) emissions accounting for cities is accurate, comparable, comprehensive, and complete. Despite recent developments in the standardization of city GHG accounting, there is still a lack of consistent guidelines regarding out-of-boundary emissions, thus hampering efforts to identify mitigation priorities and responsibilities. We introduce a new conceptual framework—based on environmental input-output analysis—that allows for a consistent and complete reconciliation of direct and indirect GHG emissions from a city. The “city carbon map” shows local, regional, national, and global origins and destinations of flows of embodied emissions. We test the carbon map concept by applying it to the greater metropolitan area of Melbourne, Australia. We discuss the results and limitations of the approach in the light of possible mitigation strategies and policies by different urban stakeholders.

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RP2007 Journal Article: Integrated Carbon Metrics and Assessment for the Built Environment

Teh, S. H., Wiedmann, T., Schinabeck, J., Rowley, H. and Moore, S. (2015) Integrated Carbon Metrics and Assessment for the Built Environment. Procedia CIRP, 29, 480-485. 

One third of global greenhouse gas emissions are emitted from the building sector contributing significantly to the problem of climate change. While more work has been done on decreasing direct emissions from the operation of buildings, embodied emissions of construction materials receive little consideration even though they constitute a significant additional proportion of emissions. The main objective of this study is to harmonise different data and methods such as Life Cycle Assessment (LCA), Input Output Analysis (IOA) and Material Flow Analysis (MFA) to accurately calculate the embodied carbon emissions of construction materials in Australia. This study will develop and streamline efficient hybrid methodologies in analysing embodied emissions of the built environment at multiple scales and develop a comprehensive database of embodied carbon LCI data for building and construction materials that will be derived from an economy-wide modelling framework. This work is part of the Cooperative Research Centre for Low Carbon Living under the Integrated Carbon Metrics project.

Access the article online

RP2007: Integrated Carbon Metrics (ICM): Scoping Study Results 2015

In order to ensure that the Integrated Carbon Metrics project meets industry and user needs a scoping study was conducted within Australia with construction industry professionals.  Results are outlined in this document.

The aim of the scoping study was to:

• Gain an understanding of the construction industry’s current approach to embodied carbon assessment;
• dentify perceived strengths and weaknesses of current embodied carbon assessment tools; and
• Identify potential areas for improvement to existing tools and recommendations for development for new embodied carbon tools.

rp2007 icm scoping study report oct 2015 final (911682 PDF)

RP2007 FACTSHEET: Integrated Carbon Metrics - A Multi-Scale Lifecycle Approach for the Built Environment

‘Embodied’ carbon in the built environment contributes an additional 18 per cent towards Australia’s overall emissions

We are developing a suite of carbon accounting tools that provide a complete picture of the carbon lifecycle, at the building, precinct and city level. The tools can inform more effective planning strategies to reduce carbon.

RP2007: Factsheet: Integrated Carbon Metrics - A Multi-Scale Lifecycle Approach for the Built Environment (824911 PDF)