There is much discrepancy over the degree of CO2-e emissions emitted from urban developments. The World Energy Outlook 2008 report claims cities produce between 67% and 71% CO2-e emissions and the Clinton Climate Initiative states that cities are responsible for 80% of emissions However, figures from the International Panel on Climate Change (IPCC) indicate that cities produce between only 30% and 40% of CO2-e emissions.The varying accounts imply uncertainty exists in the field over the boundaries of where carbon is emitted and the responsibility for its production. There is an increasing move to measure the carbon impact of all urban developments and associated infrastructure (energy supply, transport, buildings, water and waste), which contribute to the carbon consumption and production patterns of people’s lifestyles.Assessing the energy consumed within the following areas is the key to understanding what society is responsible for in terms of CO2-e emissions. These areas include: the material and construction processes involved in the built environment and its infrastructure; usage of energy within buildings; mode and usage of transport; the operational energy required for distribution and service provision of electricity, gas and water; and the management of waste. Change in any of these areas through urban development policy and design can play a major role in reducing global CO2-e emissions.
This study aimed to assist the understanding of current carbon performance and how carbon assessment can be mainstreamed in urban development. In doing this the CO2-e emissions associated with 4 types of urban settlements in Western Australia (WA) are examined, reflecting how people interact with their environment, including their varying carbon consumption and production lifestyle patterns. The 4 case studies are:Peri-urban development (greenfields) – where lifestyles are inherently more car dependent and consumption-oriented.Urban redevelopment (brownfield) – where lifestyles are more focussed on walkable and public environments rather than private consumption.Mining camps – where lifestyles are focused on daily fluctuations of intensive on-site high energy use, and then long periods where workers are off-site at their mines.Remote Indigenous communities – where lifestyles are simple but the settlement is often dependent on energy intensive infrastructure and services and can have large fluctuations in population size.The sources of CO2-e emissions identified for development of 4 community types are integrated into a framework for measuring those emissions. This research is part of an Australian Research Council project called Decarbonising Cities and Regions. The issues discussed on calculating CO2-e emissions for urban communities in WA are indicative of the challenges facing urban development world over, whether they be in big cities or in remote settlements. So lessons learnt from our research on appropriate tools for carbon governance can arguably be applied to similar locations around the globe.
The global development industry has recently witnessed a transition from an interest in building assessment tools, which focus on the overall sustainability of individual buildings (energy consumption, water use, site selection, building materials and water generation) to tools that rate the sustainability of entire developments or neighbourhoods. The shift of focus means that the CO2-e emissions of different design densities and mix, as well as the urban infrastructure (roads and public transit lines, utilities and waste collection) are all included in the assessment. It is a significant transition because with rapid urbanisation and associated infrastructure becoming increasingly interconnected and interdependent (Johansson and Hassel, 2010), established patterns of development are predicted to become harder to change in the next 20 to 30 years and urban CO2-e emissions more difficult to control (World Bank, 2010). By measuring the carbon consumption and production patterns of today’s development and infrastructure, urban design can be improved to avoid becoming locked into carbon intensive patterns in the future.
There are currently 21 different precinct-based tools under development internationally according to the International Federation of Landscape Architects (AILA et al., 2010). However, these tools have yet to address all the carbon metrics inherent in the life cycle of a community development; rather they offer frameworks for assessing the overall sustainability of a settlement. Thus, the precise nature of a carbon metric is lost in the broadly, semi-quantitative and arguably subjective nature of sustainability assessment.
An assessment tool that considers the carbon metrics for all the sources of CO2-e emissions in the lifecycle of an urban development is important for a number of reasons. It is necessary to have a design tool that can facilitate quick assessments by professionals who are seeking to create new reduced carbon development that is cost effective. It is also crucial to have the data to understand the carbon metrics and associated costs to enable traction with State and local government in their assessment processes that increasingly require reduced carbon outcomes (e.g. COAG 2009). This knowledge provides a mechanism for change versus set targets, as it provides a real measurement of CO2-e emissions. This frameworkfor the 6 sources of CO2-e emissions can enhance decision-making and allow authorities to benchmark against each other and build up a portfolio of strategies to define reduced carbon best practice. If a tool can be both a design and an assessment tool it will enable carbon management to be mainstreamed in urban development.By quantifying and analysing these sources of CO2-e emissions across various developments ranging from current practice to those that appear more sustainable, a benchmark can be achieved for optimising reduced carbon development against baseline, business as usual (BAU) alternatives. These carbon metrics are important for initiating carbon reduction strategies, e.g. lowering embodied emission materials, establishing energy efficiency strategies during operation and selecting renewable energy devices. The information will ultimately assist in determining the best combination of practices for a particular reduced carbon urban development. Such information is becoming standard practice for developers as they examine their design options and for government as they assess those options.
The full life cycle is representative of the impacts on CO2-e emissions associated withthe annual operation,manufacturing and construction processes. The diagram illustrates how the sources within the metabolism of the development are interrelated. The determination of carbon metrics for the sources, can enhance understanding on which responses are best suited for a particular development and the impact and trade-offs that might occur to CO2-e emissions in the metabolic system through these actions. For example, an action that could be implemented which directly targets the reduction of potable (drinking) water usage is to install a ‘third pipe’ system (The first pipe provides potable water and the second pipe takes waste water away). A third pipe would bring in recycled water and in doing so would reduce the amount of potable water required, therefore reducing CO2-e emissions associated with pumping the water. The effects of this strategy will bear on the following elements of the framework;Additional embodied emissions associated with the additional pipes that would be required and in the recycled water treatment plant itself.The same concept of impacts and trade-offs can be applied to transport. Land use patterns like density and mixed-use have a big impact on how much private car use is associated with a developmentEmissions associated with pumping water to and/or from the recycled water treatment plant (this could be a positive or a negative impact).
A detailed study of tools for measuring carbon was completed this year as part of the Australian Research Council “Decarbonising Cities and Regions Project”. The results identified two very different tools that, between them, fulfill the majority of the carbon metrics required to be measured for the project framework covering the 4 case studies.CCAP Precinct is a modelling tool that, as the name suggests, is a tool specifically designed to model various development options against a business as usual reference model. The reference model is based on existing data from local utility companies and the Australian Bureau of Statistics. The tool has in-built algorithms that allow some modelling to be produced with very basic levels of data at the outset. As more data around the design of a development becomes available it can be added to the model reflecting the iterative approach that forms the basis of any urban planning project.eTool is a software program that calculates the embodied and operational CO2-e emissions of buildings and civil works. It has just been released and reviews of its pre-release version have indicated its suitability to small-scale community developments. The tool is designed to calculate in detail the embodied CO2-e emissions attributable to individual buildings and structures. Later versions are expected to cater for, grouping these and assessing them at a community level. The tool is particularly suited to the remote small-scale villages of this study: mining camps and Indigenous communities, as it caters for housing, small community buildings and off-grid energy and water supply systems.The tool employs a lifecycle analysis method providing calculations of: a building’s lifespan; initial embodied energy of materials; recurring embodied energy in subsequent fit outs and maintenance; transport during construction and key aspects of operational energy. Energy associated with end-of-life aspects, such as demolition or recycling of materials are not calculated.
The Cockburn Coast development site covers 330ha of land to the South of Fremantle, of which 200ha forms prime development land and will have 4850 new dwellings, 10,000 residents and 6800 jobs, which aligns with the state development plan, Directions 2031.
Remote settlements in Australia are oftenlocated far fromtowns and support services so are typicallcharacterised by a high use of transport and thereforefossil fuel. They are alsosituated in harshclimateswhichmeansenergyisoftenrequired to maintain thermal comfort of residential and community buildings. Goods and services are alsooftenproivded by externalsuppliersincreasing the transport requirement of delivery to site.Mining camps are typicallydesigned for a temporary life span to match the expected life of the mine. Workers are oftenflown in and out of the site on rotations of one or twoweeksso air travelis a common source of carbonemissions.
The eTool software provides the energy and carboncalculations for embodiedenergy in materials for initial construction and for replacement parts and maintenance. The construction processincludingdelivery of materials and energyrequired for operation of construction equipment and travel of tradespeoplecanalsobeincluded.The direct energy use for thermal comfort, appliances and water heatingneed to becalculatedseparately, either by modelling or takingmeterreadings. ThesecanthenbeenteredintoeToolwith the energy source, such as solar PV or diesel generator, for a carbonemissioncalculation. Water systemsenergy use canbecalcuated in the samewaywith a source enteredinto the tool to calculatecarbonemissions.Transport duringoccupancy phases is not included in eToolso fuel use needs to becalculatedseparately. Embodiedenergy of infrastructure such as roadscanbecalculatedusing the sameprinciples for buildings by enteringmaterialsrequired and hours of equipment use.Wasteemissionsalsoneeds to becalculatedseparately. but simple infrastructure such as compost binsystemscanbedetermined by modellingmaterials and construction processes in eTool.
Asactual case study data isstillbeingcollected a hypotheticalexamplewasmodelledusingeTool. The 3 bedroom 2 bathroom house has a brick veneer construction withconcretetile roof. It has a design life of 35 years and isassumed to be close to trades and services for construction and maintenance. Operating energy use wasderivedfrom a study by Beale in 2006 of consumption by remotecommunities in the NorthernTerritory. The example compares twoenergysupply options: one withsolar PV as the main source of electricityconsumption, a solar hot water system and a diesel generated water supply. The second has supplybe a community diesel generator and a solar hot water system. Diesel systems are assumed to have a 3:1 primary to direct energy ratio.
The study by Bealeindicated a mid-range of operating energy use of approximately 20 kwh or 75 MJ per day. This excluded hot water heatingwhichrequired a further 36 MJ per day.
Resultsfrom the eToolmodelling show a signficantsaving of approximately 140 tonnes of CO2-e over the lifespan of the building with a solar PV system installed. While the materialrequirments for the PV system are higher the operationalsavings of carbonemissions are significant. This analysisexcludes the transport related to delivering diesel to site whichwouldfurtherincrease the emissionsavings of a solar system.
If the process of urbanization is inevitable, then it is critical that society improves its understanding of the carbon consequences of urban development. Carbon assessment tools needs to recognise settlement developments as entire metabolic systems with complex networks of infrastructure that make-up the total carbon footprint, rather than separate individual buildings. An improved understanding is required of all the components of urban carbon footprint and the sources of CO2-e emissions within the urban system. The impact that specific choices of infrastructure have on carbon flows, costs and trade-offs that result from such design decisions can then be made. This study has demonstrated that there is a very clear gap in the market for tools that provide a carbon metric to monitor CO2-e emissions in urban development. The focus remains on sustainability as a whole and it could be argued that this is due to the need for social and economic drivers to be included as part of the assessment process. That said, this research focuses on CO2-e emissions because climate change demands an urgent responseand that can only be achieved by establishing tangible, quantifiable data on CO2-e emissions, to aid realistic and appropriate reductions of set targets. There is a need for a suite of tools so that the gaps identified in construction CO2-e emissions and waste CO2-e emissions can be closed by a) identifying tools that can specifically address these gaps, or b) creating tools specifically designed to address the shortfall.
This improved knowledge of CO2-e emissions will help stakeholders understand mitigation opportunities and appropriate targets based on informed decisions of carbon consequences for delivering a portfolio of strategies for carbon reduction action. These suite of tools will help guide decision-makers on their choices of infrastructure and various initiatives for particular settlements; and propose low-carbon design choices for sites with similar circumstances. Further research into the design of methodologies and tools to fully assess carbon will only strengthen and enhance decision-making that fosters sustainable urban development.
This paper has produced a framework to identify and measure the CO2-e emissions involved in the lifecycle of a development and thereby, determine the full impact of the built environment, to facilitate carbon management. The research has shown that there are currently no tools available that meet all of the framework requirements. There are a small number of tools that tackle one or more of the CO2-e emissions sources as set out by the framework, yet only 2 tools reviewed were designed specifically to deal with 4 of the six CO2-e emissions sources. These tools are CCAPPrecinct and eTool and they have been selected as being the most appropriate for ongoing research of the case study settlements. CCAPPrecinct and eTool can model and predict the carbon consequences of various urban development pathways, as well as monitor them over time or compare them to other base-line alternatives or sustainable development projects.
Climate Change Conference Pape, Rio 2011
Carbon Assessment Tools for Urban Development Colin Beattie, Jessica Bunning, Joanne Stewart, Peter Newman, Martin AndaCurtin University Sustainability Policy Institute (CUSP), Murdoch University<br />Third International Conference on <br />Climate Change 21-22 July 2011, <br />Rio De Janeiro, Brazil<br />
Outline<br />Cities’ carbon emissions<br />Research project model<br />Carbon Assessment Tools<br />Framework & Model for Sources of CO2-e Emissions<br />CCAPPrecinct and e-Tool<br />Case studies<br />
Cities and CO2-e Emissions<br />Cities play a major role in build-up of CO2-e emissions in global atmosphere<br />Varying reports of degree of contribution<br />Uncertainty of location and direct responsibility for CO2-e emissions in cities<br />Need to measure CO2-e outputs of urban developments and determine CO2-e impacts of infrastructure (energy supply, water, waste, transport)<br />Need to quantify CO2e emissions involved in: <br />material & construction processes in built environment & infrastructure; <br />usage of energy within buildings; <br />mode and usage of transport; <br />operational energy required for distribution and service provision of electricity, gas and water; <br />and the management of waste<br />
Research Project Model<br />Decarbonising Cities and Regions: Australian Research Council Linkage Grant<br />Western Australian Case Studies:-<br />Cities<br />Urban development (greenfield): lifestyles more car dependent, consumer orientated<br />Urban redevelopment (brownfield): lifestyles more focused on walkable/public environments vs private consumption<br />Regions<br />Mining camps:lifestyles focused on daily fluctuations of intensive on-site high energy use, and then long periods where workers are off-site at their mines<br />Remote Indigenous communities: lifestyles are simple but the settlement is often dependent on energy intensive infrastructure and services and can have large fluctuations in population size <br />
Carbon Assessment Tools<br />Global development industry transition:<br />
Carbon Assessment Tools<br />21 different precinct-based tools (AILA) e.g. US’s LEED-ND; UK’s BREEAM Communities; Australia’s Green Star–Communities<br />Yet to address carbon metrics in life cycle of a development – but offer frameworks for assessing overall sustainability of a settlement<br />Precise nature of a carbon metric is lost in the broadly, semi-quantitative and arguably subjective nature of sustainability assessment <br />
Framework for Sources of CO2-e Emissions in Urban Development<br />
Cockburn Coast –<br />The High Performance Case...<br />KEY FINDING: Improvements in performance from implementing green infrastructure achievable at only $5,600 per dwelling<br />* Excluding the cost of light rail<br />Plus increased affordable housing<br />17<br />
Operating energy from study of remote communities (Beale, 2006)
Excludes embodied energy of community diesel generators
Comparison of two options:</li></ul>Solar PV for electricity generation, solar hot water system and community diesel water supply system<br />Community diesel generator for electricity generation and solar hot water system<br />
Comparison of solar PV and diesel<br />CO2-e (tonnes)<br />
Discussion<br />Critical need for improved understanding of CO2-e consequences of urban development - as entire metabolic system<br />There is a gap in tools’ market for carbon metric to monitor CO2-e emissions<br />Need to establish quantifiable data on CO2-e emissions <br />Need a suite of tools so gaps in construction and waste CO2-e emissions can be closed by:<br />a) identifying tools to address gaps <br />b) creating tools specifically designed to address shortfalls<br />
Discussion<br />Recognise importance of linkages across the framework model for holistic outcome<br />Information will:<br />guide decision-makers on choices of infrastructure and low carbon design initiatives for sustainable urban development <br />assist stakeholders understand mitigation opportunities and appropriate targets for delivering strategies for carbon reduction action<br />
Conclusion<br />This study has produced a framework to identify and measure CO2-e emissions in life cycle of a development<br />Research has shown no tools meet all requirements of the framework except - <br />CCAPPrecinct and eTool, which can efficiently model and predict the carbon consequences of various urban development pathways, and monitor them over time or compare them to other base-line alternatives or sustainable development projects. <br />
Thank you<br />Acknowledgements:<br /> Australian Research Council (ARC)<br />the ARC Curtin University Sustainability Policy Institute (CUSP), Murdoch team : Vanessa Rauland, Colin Beattie, Jessica Bunning, Joanne Stewart, David Goodfield<br />Parsons Brinkerhoff (PB), Kinesis<br />Horizon Power<br />Cedar Woods<br />North Port Quay<br />