Accounting for carbon in the planning for residential neighbourhoods
Cover page
Project number: 6-020
Project title: Accounting for carbon in the planning for residential neighbourhoods
Milestone number: 1
Deliverable name: Interim Report: Case study area emissions
Funding acknowledgment: This research is funded by iMOVE CRC and supported by the Cooperative Research Centres program, an Australian Government initiative.
Report authors: Bill Grace, Julian Bolleter, Chris Lund from the Australian Urban Design Research Centre (AUDRC)
Date: 14 01.25
Version: C
Figure 42 Impact of rooftop solar. .........................................................................................
Figure 43 The pIanning interventions workshop.
Figure 44 An initial planning intervention for the Nollamara precinct includes coordinated low to medium-rise apartment buildings along a central transit corridor (Nollamara Avenue) and reducing ad-hoc background infill throughout the broader suburban expanse. This intervention is based on feedback from the planning interventions workshop and State Planning Policy 7.2 - Precinct Design. 59
1. Introduction
1.1 Context
Climate change is an ongoing challenge, having both global and local impacts. According to the United Nations Environment Program (UNEP) estimates suggest that cities are responsible for 75 percent of global COz emissions with transport and buildings being amongst the largest contributors 1. Greenhouse gas emissions must be reduced to mitigate against more severe climate change, and adaptations must be implemented to manage the impacts of changes already underway. Western Australia’s (WA) Climate Policy, released by the State Government in 2020, sets an aspiration for net zero GHG emissions by 2050, with the State Sectoral Emissions Reduction Strategy 2 released at the end of 2023. For buildings it discusses the need to reduce both direct (activity based) emissions as well as selecting products and materials with lower embodied emissions being critical to the decarbonisation of the buildings sector. WA Climate legislation is also being developed to embed the net zero GHG emissions by 2050 target in law, including annual GHG reporting through parliament. The Commonwealth has legislated through the Climate Bill a 43% reduction in GHG emissions by 2030. At the international level – the most recent UN IPCCC assessment report, AR6 working Group III report 3 has stated that significant emissions reduction is needed this decade to avert dangerous climate change ideally to a 1.5C warming or less.
Given the significant contribution of cities to global GHG emissions understanding how structure planning processes for new residential neighbourhoods can best contribute to reducing greenhouse gas emissions is a priority. This should consider how accounting for emissions can be accomplished at the planning stage and followed through to the implementation and delivery stages. There is a need to include a methodology for the assessment of planning intent, as well as more detailed consideration through construction and operation.
WA’s State Planning Policy (SPP 7.2) includes a requirement for precinct structure planning to consider greenhouse gas emissions reduction and incorporation of renewable energy sources, as well as the preparation of an Energy and Greenhouse Gas Emissions Statement. The Statement outlines and demonstrates how the planning and proposed design of a precinct plan area reduces greenhouse gas emissions over Business as Usual approaches and incorporates renewable energy sources.
This project is of considerable importance as the impact of poor planning of new residential areas significantly contributes to the locking in of GHG emissions into the future, up to 50 years. This research will provide an evidence base and tools to support better decision-making and assessment in the planning and design of new neighbourhoods.
2 Government of Western Australia (2023) “Sectoral emissions reduction strategy for Western Australia Pathways and priority actions for the state’s transition to net zero emissions” . https://www.wa.gov.au/system/files/202403/sectoral-emissions-reduction-strategy-western-australia_0.pdf
The research considers the physical and social geography factors of new, predominantly residential neighbourhoods in metropolitan Perth and Peel and how planning and design impact the behaviour of residents, including factors affecting travel, transport and access to places of work, services and entertainment. The work will also inform planning and design in regional areas of Western Australia.
The overarching scope of the research is to:
• examine how the design of new greenfield and existing densifying neighbourhoods can reduce carbon emissions and contribute to the creation of low or zero-carbon neighbourhoods;
• identify the primary contributors to greenhouse gas emissions in neighbourhoods and how emissions can be reduced through urban planning and design interventions related to subdivision patterns, street networks, open space systems, residential densities, building types, and environmental conditions;
• determine how the modelling and reporting of emissions would occur at the district and local structure plan stages and how these could be followed through to implementation; and
• establish key indicators and assessment methodologies applicable at the district and local structure planning stages for residential areas.
1.3 Project governance
The project steering committee comprises senior officers from the Departments of Transport (DoT), Planning Lands and Heritage (DPLH) and the iMOVE Cooperative Research Centre. DPLH has established a working group to guide the project.
1.4 Phase 1 scope
The first phase of the research reported here involves the assessment of life-cycle emissions in characteristic Perth metropolitan precincts, representing:
• conventional contemporary greenfield developments and
• infill developments.
The emissions inventory comprises a subset of all emissions as follows:
• emissions associated with the construction of subdivisions, including materials, transport, construction equipment and the clearing of vegetation;
• emissions associated with the construction of residential built form;
• emissions associated with the operational energy (electricity and gas) used in residential dwellings;
• emissions associated with vehicle transport associated with each precinct;
• emissions sequestered by vegetation planted during development;
• emissions associated with the supply of water and wastewater services.
This report is in two volumes. This Volume 1 provides an overview of the approach to measure emissions, outlines the results of the analysis for each precinct, and identifies the main impacts on
emissions from location, urban and built form. The detailed methodology developed to measure emissions is set out in Volume 2.
1.5 Acknowledgements
The research team acknowledges the cooperation of several parties in providing information and support for the analysis presented here:
• The members of the Steering Committee;
• Members of the DPLH Working Group;
• Officers of DPLH, DoT and DWER; and
• For the provision of data: Western Power, ATCO, Water Corporation and the local governments of Wanneroo, Gosnells, Stirling and Swan.
2. The case study precincts
2.1 Selection
The study involves five case study precincts, three urban-edge greenfield and two urban infill as nominated by the Department of Planning Lands and Heritage Working Group (see Table 1). The case studies were selected to represent contemporary development patterns, so our findings are ‘generalisable’ to structure plan areas in the future. Specifically, the chosen case studies represented:
• A diversity of urban morphologies (e.g., precinct configurations, street layouts, building types and open space structures);
• Different planning policies (e.g., State Planning Policy 4.2 or 7.2);
Subi Centro Subiaco Redevelopment Act 1994 1994 Transit Oriented Development Activity Centre policy (State Planning Policy 4.2) Precinct Design (State Planning Policy 7.2)
The analysis of development/ redevelopment within each precinct relates to a baseline year when the corresponding Structure Plan was approved
1 The case study precincts
2.2 Sourced information
Spatial information on the case studies has been drawn from multiple sources:
• Building footprints:
o ‘Ai Deep Learning’ Buildings 2023 (Landgate -468) ; and
o Building Footprints 2017 (Landgate)
• Cadastre 2023 (DPLH)
• ‘Ai Deep Learning’ Pools 2023 (LGATE-479).
• ‘Ai Deep Learning’ Solar Panels 2022 (Landgate -481).
• Structure Plan Boundaries 2023 (DPLH)
• Structure Plan Landuses 2023 (DPLH); and
• Transport Zones 2023 (DoT).
Within each case study, a fine-grained analysis of building types (based broadly on morphology) was conducted to inform calculations regarding energy/ emissions. Criteria we used to identify the building types in the precincts generally included:
• Whether the dwelling was detached, semi-detached or attached;
• The number of storeys;
• The lot width; and
• Whether the dwelling was front or rear-loaded.
Figure
Additional criteria we used to identify the apartment building types in the Transit Oriented Development precinct (Subiaco) included:
• Whether the building was low-rise/ medium-rise or high-rise; or
• Whether the building was single or double loaded
Additional criteria we used to identify the building types in the background infill precinct (Nollamara) included:
• Whether the lot arrangement consists of a separate house on a lot, or houses on small subdivided lots
These typologies will also be used in developing planning interventions for the case studies in subsequent stages. Please note that non-residential buildings were not included in our building type analysis, although the residential dwellings in mixed use buildings in Subiaco were included.
3. Methods
A summary of the methods used to measure emissions is set out below. Note that in all cases the emissions intensity has been based on current values. Further detail is provided in Volume 2 of this report.
3.1 Subdivision works
The emissions associated with subdivision works in greenfield precincts were evaluated using life cycle assessment (LCA) methods. The initial intention was to obtain the source data from the developers of each of the greenfield precincts through the cooperation of the Urban Development Institute of Australia (UDIA). However, the introductions to those developers were not made and so we were unable to source the requisite information. The evaluation reported here is based on a previous LCA study carried out by Cerclos for the UDIA 4 for the following projects:
• 115 Hamilton Hill (DevelopmentWA) – a residential estate;
• Bushmead (Cedar Woods) - a residential estate; and
• Orion (DevelopmentWA) – an industrial estate
Accordingly, the results are not an accurate representation of subdivision works for the specific precincts studied in the research reported here but are believed to be sufficiently indicative to support the general findings of this study.
The Cerclos study comprises a complete evaluation of life-cycle emissions in accordance with the following:
• International Standards ISO 14040 and 14044; and
• European Standard EN 15978: Sustainability of Construction Works – Assessment of Environmental Performance of Buildings – Calculation Method.
This full LCA process adopted by Cerclos involved the assessment of impacts during the construction, use and end-of-life phases of the project. For this study, only the construction phases of the subdivision works were evaluated
3.2 Built Form
Cadastral information for each precinct was sourced from Landgate and complemented by aerial imagery (Google Street View and Nearmap). Each dwelling was categorised according to the variables set out in Section 2 above.
3.2.1
Embodied emissions
Construction information obtained from building permits for the random selection of lots in each category was sourced from the relevant local government. At the time of writing, building permit information had been received from the Cities of Wanneroo, Swan, and Gosnells but is still awaited from the Cities of Stirling and Subiaco.
4 Land Development Infrastructure Life Cycle Assessment Study (July 2023)
From this information, LCA techniques were used to evaluate the embodied carbon in the main envelope elements of the buildings (construction phases) as these are the phases that can be influenced by planning and building codes. Cerclos’s eTool software was used for this analysis 5 Further details on the methodology are set out in Volume 2.
When buildings are demolished as in the case of Nollamara and Subiaco to facilitate redevelopment, emissions are created in the works phase and in subsequent recycling and / or landfill. These emissions are difficult to evaluate and have been neglected in this analysis.
3.2.2 Operational energy - dwellings
The National Construction Code (NCC) requirements (ref) facilitate an assessment of operational energy use for a dwelling to comply with the current seven-star standard. This assessment has been conducted for each of the identified typologies, noting, however, that the results are essentially related to the habitable area of the dwelling in all cases. This assessment has enabled the creation of a benchmark against which actual energy use can be compared. The method of analysis is described in detail in Volume 2.
Data on the actual energy use of each typology within each precinct was sought from Western Power and ATCO. Although requested, and agreeing to do so, at the time of writing Western Power had yet to provide the required information at the typology level but had provided summaries of energy use in residential premises at the suburb level. Similarly, ATCO advised that their systems did not allow them to provide the level of detail requested. However, they did provide energy use data at the suburb level. This data has been used to assess the operational energy use of dwellings compared to the theoretical and NCC calculations.
The Western Power data identifies the energy exported to their network from rooftop solar PV arrays and the energy imported to premises from the network. Using an in-house developed solar PV model, the capacity of solar PV (at the suburb level) has been assessed to identify the energy that is self-supplied and, therefore, the total electricity demand of households on average. The method is explained further in Volume 2.
The greenhouse gas intensity of electricity and gas has been taken from the Australian National Greenhouse Accounts Factors (2023) 6 published by the Department of Climate Change, Energy, the Environment and Water.
3.3 Operational energy – transport
There is no reliable data that enables the emissions from vehicles to be determined. This study has relied on results from the Strategic Transport Evaluation Model (STEM) of Metropolitan Perth and Peel held within the DoT. DoT has provided the research team with model results that identify transport zones (TZ) associated with the selected precincts:
• vehicle kilometres travelled (VKT) related to travel to and from the transport zones for private vehicles, light commercial vehicles and heavy commercial vehicles; and
5 https://etool.app/
6 Australian Government Department of Climate Change, Energy the Environment and Water 2023 “National Greenhouse Accounts Factors:2023”. https://www.dcceew.gov.au/climatechange/publications/national-greenhouse-accounts-factors-2023.
• the number and purpose of trips to and from those transport zones.
DoT has recently commissioned a consultancy report to create a framework for evaluating road transport emissions, and provided excerpts to the research team from this report that provides emissions intensity values for various vehicle types. Those values have been applied to the VKT reported from the stem model to assess vehicle emissions associated with each precinct.
The analysis does not include emissions from public transport, i.e. from bus and train use of occupants of the precincts. Data to enable these emissions to be incorporated in the modelling phase of the project will be sought.
Similarly, the embodied energy / emissions in private vehicles has not be calculated as this is not a variable that can be influenced by planning and design policies.
3.4 Vegetation
Each case study was individually analysed based on its characteristics and available information. For each case study, a baseline year was established just prior to significant change or development activity. For the baseline year, the amount of vegetation (including grass (lawns, verges, reserves and ovals), shrubs and trees) in place was estimated and compared with the amount of vegetation now (2023/2024) using a range of tools, including Nearmap, Google Earth Pro and Google Street View.
Figure 2 DoT Transport zones.
An estimate of carbon dioxide emissions and removals was then developed over a 50-year period based on each case study’s quantified vegetation changes and applying a range of carbon dioxide removal values determined through a combination of research and a carbon accounting tool called FullCAM 7 managed by the Department of Climate Change, Environment and Water (see Volume 2)
Further details on the methodology are set out in Volume 2, together with a detailed analysis of vegetation loss and gain for the precincts.
3.5 Water and wastewater emissions
Operational emissions arise from treating raw water sources (e.g. groundwater and seawater for desalination) and transport through the Integrated Water Supply Scheme (IWSS) to its place of use. Emissions from the wastewater system arise from transporting wastewater from its origin to the Water Corporation’s wastewater treatment plants and its treatment and disposal (including the component of wastewater that supplies the Groundwater Replenishment Scheme).
The Water Corporation has provided data on water use from 2022 to the present for all meters within each precinct. Average water usage was calculated from this data. Wastewater volumes have been estimated based on the quantity of water used and the type of lot. Larger lots, which typically have more external water uses, such as irrigation swimming pools/spas, return a lower proportion of water to the wastewater system than smaller lots.
The Water Corporation’s Annual Report 8 includes data on the energy use per kilolitre of water and wastewater and the overall greenhouse gas emissions per unit of energy consumed. This information has been used to translate water and wastewater flows to annual greenhouse gas emissions.
The Jindalee case study is located near the coast in the northern Perth metropolitan area, some 40 km from the Central Business District (CBD). The local government is the City of Wanneroo. The development is subject to the following:
• Consolidated Butler Jindalee District Structure Plan No.39 Amendment 1; and
• the Jindalee North Structure Plan 88 Amendment 2 (Figure 3)
Figure 3 Jindalee North Structure Plan map.
Figure 4 Jindalee precinct GIS base.
Figure 5 The Jindalee case study area
The majority of the site is zoned R30 / R60, while the coastal activity node is zoned R100. The site area is approximately 120 ha, and the gross density is currently 11.1 dwellings per ha.
At the time of writing, the lower-density zones of the precinct are significantly developed (see Figure 6), while the R100 zone is undeveloped.
2024).
The development is characterised by medium-sized lots with high site coverage (see Figure 7) and some narrow laneway lots (Figure 8)
Figure 6 Jindalee (Feb
Figure 7 Jindalee development pattern
4.2 Sub-division works
The Cerclos report prepared for the UDIA study was used to establish the approximate emissions created by the sub-division works. The estimate in Table 2 below is indicative only.
Table 2 Jindalee - subdivision emissions
4.3 Built form
4.3.1 Building typologies
The Jindalee dwellings have been categorised into the following typologies (see Error! Not a valid bookmark self-reference.). The building types are generally detached, single-storey dwellings with high site coverage.
Table 3 Jindalee dwelling typologies
Figure 8 Jindalee laneway lots
4.3.2
Built form construction
The City of Wanneroo provided a sample of building permits from each of the typologies. This information was used to determine the main construction materials used in the building envelope, i.e. ground floor and external walls and roof. The construction comprised a conventional reinforced concrete floor slab and double brick external walls in all cases. Approximately 85% of the dwellings sampled had conventional steel roof covering, with the balance being tiles.
4.3.3
Built form emissions
The annual energy demand (electricity and gas) was calculated for each typology and is set out in Table 4 below, together with the calculated embodied emissions from the eTool analysis. The average Jindalee house has a 2.53 kW rooftop solar array.
Table 4 Jindalee – built form emissions summary
Figure 9 Typical Jindalee building types
Operational and embodied emissions are strongly related to gross floor area, as depicted in Figure 10
Figure 10 Jindalee built form emissions.
4.4 Transport emissions
The results from the STEM modelling are set out in Error! Reference source not found.. The model results provided relate to two transport zones (Alkimos and Jindalee) and reflect private car trips that are generated within the study area for all home – based purposes (Work, Education, Shopping, Others) and not-home based trips.
Table 5 Jindalee - transport emissions from private car use
4.5 Emissions from vegetation loss and gain
Land clearing results in the loss of continuous sequestration (i.e. carbon removal) of atmospheric CO2, offset by plantings as part of the landscaping of new developments. The summary of assessment for Jindalee is set out in Table 6 below. The detailed assessment is included in Volume 2
Table 6 Jindalee - emissions from vegetation loss/gain
Item/Description
Total Development Area (m2)
Uncleared Area (m2)
1,100,000 Source - Satterley (110 hectares)
32,828 Assumption based on time series data from Nearmap observations, identification of conservation area in Satterley Master Plan and cadastre data
% of Development Uncleared Area 3.0%
Total land cleared (m2) 1,067,172
Portion of Coastal Landscapes
Coastal Landscapes Area (m2)
40% Source - City of Wanneroo Street Tree Master Plan - Fig 32 (estimate)
426,869
Portion of Dunes Landscapes 60% Source - City of Wanneroo Street Tree Master Plan - Fig 32 (estimate)
Dunes Landscapes Area (m2)
640,303
Total Recreational Areas (m2) 90,668 Based on Nearmap area analysis
% of Development 8.2%
Total Residential Areas (m2) 976,504 Remainder from Total land cleared and Total Recreational Areas
% of Development 88.8%
Vegetation Carbon Impact - 50-year
Life-cycle
Emissions from Clearing 15,277 tonnes of CO2 equivalent Carbon Removal from Planting (1,593) tonnes of CO2 equivalent
Total Carbon Emissions 13,683 tonnes of CO2 equivalent
See Volume 2 for pictures and descriptions of the different vegetation landscapes.
4.6 Emissions from water and wastewater
Estimated emissions from the use of water and disposal of wastewater are set out below in Table 7 on a per-dwelling basis.
Table 7 Jindalee - water and wastewater emissions
JINDALEE Houses/villas
pa)
pa)
5. Southern River
5.1 Precinct description
The Southern River case study is located in the southeastern Perth metropolitan area, 25 km from the Central Business District (CBD). The local government is the City of Gosnells. The development is subject to the Southern River Precinct 3A Outline Development Plan.
The land is zoned for residential development at predominantly R20 with pockets of R30 and R40. The precinct has two lots zoned for commercial development, a primary school and some 2.86 ha of public open space. The site area is approximately 63 ha, and the gross density is 10.7 dwellings per ha.
Figure 11 Southern River ODP Map
Figure 12 Southern River precinct GIS base.
At the time of writing, the precinct is substantially developed (see Figure 13) and characterised by high levels of site coverage on most lots (see Figure 14).
Figure 13 Southern River - current development status.
14
5.2 Sub-division works
The Cerclos report prepared for the UDIA study was used to establish the approximate emissions created by the sub-division works. The development is in the southeast portion of the metropolitan area, where groundwater is typically shallow. Therefore, development requires substantial quantities of fill and (often) subsoil drainage. The Bushmead precinct considered in the Cerclos report also required substantial fill, and this has been used as the template for estimating subdivision works for this precinct. The estimate in Table 8 below is indicative only.
Table 8 Southern River - subdivision emissions
5.3 Built form
5.3.1 Building typologies
The Southern River dwellings have been categorised into the following typologies (see Table 9).
Figure
Southern River - typical development pattern
Table 9 Southern River - building typologies
5.3.2 Built form construction
The City of Gosnells provided a sample of building permits from each of the typologies. This information was used to determine the main construction materials used in the building envelope, i.e. ground floor and external walls and roof. The construction comprised a conventional reinforced concrete floor slab and double brick external walls in all cases. Approximately 85% of the dwellings sampled had conventional steel roof covering, with the balance being tiles.
5.3.3 Built form emissions
The annual energy demand (electricity and gas) was calculated for each typology and is set out in Table 10 below, together with the calculated embodied emissions from the eTool analysis. The average Southern River house has a 2.14kW rooftop solar array.
Table 10 Southern River - built form emissions summary.
Operational and embodied emissions are strongly related to gross floor area, as depicted in Figure 15
Figure 15 Southern River built form emissions.
5.4 Transport emissions
The results from the STEM modelling are set out in Table 11. The model results provided relate to the Huntingdale transport zone (which is larger than the Southern River precinct) and reflect private car trips that are generated within the study area for all home – based purposes (Work, Education, Shopping, Others) and not-home based trips.
Table 11 Southern River - transport emissions from private car use
5.5 Emissions from vegetation loss and gain
The summary of the assessment for Southern River is set out in Table 12 below. The detailed assessment is included in Volume 2.
Table 12 Southern River - emissions from vegetation loss/gain Item/Description
Total Residential Areas (m2)
of Development
Vegetation Carbon Impact - 50-year
Based on Nearmap area analysis
Remainder from Total land cleared and Total Recreational Areas (ha) less Athletic Field
Carbon Removal from Planting (353) tonnes of CO2 equivalent
Total Carbon Emissions 8,910 tonnes of CO2 equivalent
Estimated emissions from the use of water and disposal of wastewater are set out below in Table 13 on a per-dwelling basis.
Table 13 Southern River - water and wastewater emissions
SOUTHERN RIVER Houses/ villas
Consumption (kL/dwelling pa)
Water 210 Wastewater 168
Emissions (kgCO2e/dwelling pa) Water 281
114 Total 395
6. Ellenbrook
6.1
Precinct description
Ellenbrook, in the northeast of the metropolitan area, has been developing incrementally since 1991. It is twenty-two kilometres north-east of the Perth CBD and twenty kilometres from the district centre of Midland The precinct selected for study is in the north of Ellenbrook, known as Charlottes Vineyard (
Figure 16), with the first lots developed in 2003
Figure 16 the Ellenbrook precinct GIS base
The precinct is almost completely developed and is characterised by an irregular street layout and compact development ( Figure 17). The site area is approximately 207 ha, and the gross density is 7.3 dwellings per ha.
The precinct has a wide variety of zones, with several large R5 and R10 lots and smaller R40 lots, most of which are between those densities (Figure 18). The average freehold lot size is 650m2, and the median is 592m2.
Figure 17 Ellenbrook - Charlottes Vineyard built form.
6.2 Sub-division works
The Cerclos report prepared for the UDIA study was used to establish the approximate emissions created by the sub-division works. The development is in the northeast portion of the metropolitan area, where groundwater is typically shallow. Therefore, development requires substantial quantities of fill and (often) subsoil drainage. The Bushmead precinct considered in the Cerclos report also required substantial fill, and this has been used as the template for estimating subdivision works for this precinct. The estimate below is indicative only.
Table 14 Ellenbrook – subdivision emissions
Figure 18 Charlottes Vineyard zoning
6.3 Built form
6.3.1 Building typologies
The building typologies have been categorised at Charlottes Vineyard in Ellenbrook by analysing a sample of 730 lots (see Table 15
Table 15 Ellenbrook building typologies
6.3.2 Built form construction
The City of Swan provided a sample of building permits from each of the typologies. This information was used to determine the main construction materials used in the building envelope, i.e. ground floor and external walls and roof. The construction comprised a conventional reinforced concrete floor slab and double brick external walls in all cases. Approximately 78% of the dwellings sampled had conventional steel roof covering, with the balance being tiles.
6.3.3 Built form emissions
The annual energy demand (electricity and gas) was calculated for each typology and is set out in Table 16 below, together with the calculated embodied emissions from the eTool analysis. The average Charlottes Vineyard house has a 2.63 kW rooftop solar array.
Table 16 Ellenbrook - built form emissions summary
Emissions are related to gross floor area, as illustrated in Figure 19
6.4 Transport emissions
The results from the STEM modelling are set out in Table 17. The model results provided relate to several transport zones surrounding and including the Ellenbrook precinct and reflect private car trips that are generated within the study area for all home – based purposes (Work, Education, Shopping, Others) and not-home based trips.
Table 17 Ellenbrook - transport emissions from private car use
per dwelling
per trip
6.5 Emissions from vegetation loss and gain
The summary of the assessment for Ellenbrook is set out in Table 18 below. The detailed assessment is included in Volume 2
Figure 19 Ellenbrook - built form emissions.
Table 18 Ellenbrook - emissions from vegetation loss/gain
Item/Description Area (m2)
Comment
Total Development Area (m2) 1,685,853 Nearmap measurement
Uncleared Area 111,971
% of Development Uncleared Area 6.6%
Total land cleared (m2) 1,573,882
Assumption based on time series data from Nearmap observations
Total Recreational Areas 231,399 Based on Nearmap area analysis
Total Residential Areas 1,342,483
Remainder from Total land cleared and Total Recreational Areas % of Development 79.6%
Estimated emissions from the use of water and disposal of wastewater are set out below in Table 19 on a per-dwelling basis.
Table 19 Ellenbrook - emissions from water and wastewater
ELLENBROOK Houses/villa s Apartments, Units & Flats
7. Nollamara
7.1
Precinct description
The DPLH Working Group selected Nollamara as a typical example of “background infill,” which occurs when suburbs are rezoned to facilitate subdivision. The area selected for study (Figure 20) is bordered by Balcatta to the west and Dianella to the east and is around 78 ha Nollamara Avenue runs centrally from west to east through the precinct.
Within this area, there are 1,655 lots, of which 35% are freehold lots, 13% survey strata lots, and 52% built strata lots. There are very few single dwellings on large original lots remaining. The survey strata lots date from 2002, and the built strata lots from 1992. The City of Stirling Planning Scheme No. 3 applies to the area. The site area is approximately 80 ha, and the gross density is 21.4 dwellings per ha.
Figure 21 and Figure 22 illustrate the typical form of development (noting this image shows two remaining single-dwelling lots).
Figure 20 Nollamara precinct GIS base
7.2 Sub-division works
As this research aims to determine the emissions impact of planning decisions, the sub-division works for Nollamara have been neglected, as this occurred when the suburb was first developed in the twentieth century. It is assumed that there is little additional subdivision works required during the conversion of the large lot to smaller lots.
7.3 Built form
7.3.1 Building typologies
There are many forms of dwellings in the Nollamara precinct. These have been categorised as shown in Table 20.
Figure 21 Nollamara - typical development pattern
Figure 22 Nollamara - multiple dwelling lots
Table 20 Nollamara - built form typologies Typology Detached/ Attached
Notes
91 Any small, attached residence. Residents only own one floor. Often, many residents in one attached building.
135 Separate house on lot
146 Detached, singlestorey homes that were on small, subdivided blocks.
137 All single-story semiattached houses.
205 All two-storey semiattached houses. 3
181 Many blocks with multiple residences on one property.
238 Many blocks with multiple residences on one property.
7.3.2 Built form construction
At the time of writing, the City of Stirling has not provided the requested building permit samples. Accordingly, it has not been possible to determine the construction materials used accurately. For this research phase, it has been assumed that all dwellings are constructed of concrete floor slabs, double brick walls, and a combination of steel and tile roofs, as in other suburbs.
7.3.3
Built form emissions
The annual energy demand (electricity and gas) was calculated for each typology and is set out in Table 21 below, together with the calculated embodied emissions from the eTool analysis. The average Nollamara dwelling has a 0.94 kW rooftop solar array.
21
Emissions are strongly related to gross floor area, as illustrated in Figure 23
7.4 Transport emissions
The results from the STEM modelling are set out in Table 22. The model results provided relate to several transport zones surrounding and including the Nollamara precinct and reflect private car trips that are generated within the study area for all home – based purposes (Work, Education, Shopping, Others) and not-home based trips.
Table 22 Nollamara - transport emissions from private car use
Table
Nollamara - built form emissions
Figure 23 Nollamara built form emissions.
7.5 Emissions from vegetation loss and gain
The summary of assessment for Nollamara is set out in Table 23 below. The detailed assessment is included in Volume 2.
Table 23 Nollamara - emissions from vegetation loss and gain
Item/Description
Total Development Area (m2)
798,057 Source Nearmap (79.81 ha)
Uncleared Area (m2) 0 Assumed that the full development was cleared prior to the baseline year
% of Development Uncleared Area 0.0%
Total land cleared (m2)
798,057
Total Recreational Areas 26,142.0 Based on Nearmap area analysis (2.6ha)
% of Development 3.3%
Total Residential and other Developed Areas (m2)
764,349 Remainder from Total land cleared and Total Recreational Areas (ha) less Athletic Field
% of Development 95.8%
Vegetation Carbon Impact - 50-year Lifecycle
Emissions from Clearing due to Urban Infill 974 tonnes
Estimated emissions from the use of water and disposal of wastewater are set out below in Table 24 on a per-dwelling basis, together with water used for common residential properties, which is metered separately.
Table 24 Nollamara - emissions from water and wastewater
NOLLAMARA Houses/ villas Apartments, Units & Flats Townhouse / Terrace house
8. Subiaco
8.1 Precinct description
Subi Centro originally occupied more than 80 hectares of former industrial land bounded by Salvado Road, Jersey Street, Roberts Road, Hay Street and Haydn Bunton Drive to the north of the Rokeby Road main street.
In 1990, before redevelopment authority intervention in Subiaco, the Subiaco 2000 Concept Plan was released. In 1995, following the establishment of the Subiaco Redevelopment Area (SRA), the Subiaco Redevelopment Area Concept Plan, often referred to as the Subiaco Indicative Development Plan, was launched. The SRA undertook several reviews of the concept plan to reflect the completed development and guide the final design for the remaining development sectors. Refer to Figure 24
Figure 24 Indicative Development Plan Subiaco 2009
Between 1996 and 2018, the Subi Centro project was subject to the Subiaco Redevelopment Scheme. In March 2018, this Scheme was repealed and replaced by Subiaco Redevelopment Scheme # 2. Scheme 2 provided the basis for development and land use control for the Subi Centro and the Subi East Project Areas). Subi Centro Precinct as of 2018 included:
• Centro Place Precinct
• Bishop Street Precinct.
• Australian Fine China Precinct
• Centro North Precinct.
• Hood Street Precinct; and
• Carter Lane
The area is now all controlled by the Local Planning Scheme No. 5 which contains precincts and sub-precincts.
The DPLH Working Group has selected an area within Subiaco encompassing somewhat more than the original SubiCentro area, now representing the Subiaco Activity Centre under State Planning Policy 4.2 Activity Centres for Perth and Peel The area is around 73.5 ha, shown below (green boundary) in Error! Reference source not found.. Most of the area is zoned “Centre” in LPS No.5. The site area is approximately 79 ha, and the gross density is 37 dwellings per ha.
New residential development in the north of the precinct is characterised by a mix of apartments (Figure 26) and townhouses (Figure 27).
Figure 25 Subiaco precinct GIS base.
Figure 26 Subiaco - apartments
Figure 27 Subiaco - townhouses
8.2 Sub-division works
As the objective of this research is to determine the emissions impact of planning decisions, the subdivision works for Subiaco have been neglected, as this occurred when the suburb was first developed in the twentieth century.
8.3 Built form
8.3.1 Building typologies
There is a range of building types in the Subiaco precinct. These have been categorised into the built form as set out in Table 25
Table 25 Subiaco - built form.
Note that Typologies LD, LS, HR, MD and MS relate to apartment dwellings which are usually the upper floors of mixed use buildings.
8.3.2 Built form construction
Unfortunately, the City of Subiaco has not at the time of writing provided the requested building permit samples. Accordingly, it has been assumed that the single dwelling typologies (HS, AHD, AHT)
are of similar construction as the other precincts (i.e. predominantly concrete slab, double brick walls and steel or tile roof.
For the apartment blocks (LD, LS, HR, MD, MS), the eTool benchmark examples of multi-residential buildings (Example Residential Projects (eTool Default)) have been relied on, which are based on a standard concrete multi- storey building
8.3.3 Built form emissions
The annual energy demand (electricity and gas) was calculated for each typology and is set out below in Table 26, together with the calculated embodied emissions from the eTool analysis. The average Subiaco dwelling has a 1.7 kW rooftop solar array.
Table 26 Subiaco built form emissions
8.4 Transport emissions
The results from the STEM modelling are set out in Table 27.The model results provided relate to several transport zones surrounding and including the Subiaco precinct and reflect private car trips that are generated within the study area for all home – based purposes (Work, Education, Shopping, Others) and not-home based trips.
The model results relate to several transport zones of which the precinct represents around 16% of the number of dwellings.
Table 27 Subiaco - vehicle emissions from private car use
8.5 Emissions from vegetation loss and gain
The summary of the assessment for Subiaco is set out in Table 28 below. The detailed assessment is included in Volume 2.
Table 28 Subiaco - Emissions from vegetation loss/gain
Item/Description
Total Development Area (m2)
790,112 Source Nearmap (79.01 ha)
Uncleared Area (m2) 0 Assumed that the full development was cleared prior to the baseline year
% of Development Uncleared Area 0.0%
Total land cleared (m2)
790,112
Total Recreational Areas 82,461 Based on Nearmap area analysis (8.2ha)
% of Development 10.4%
Total Residential and other Developed Areas
707,651 Remainder from Total land cleared and Total Recreational Areas (ha)
Estimated emissions from the use of water and disposal of wastewater are set out below in Table 29 on a per-dwelling basis, together with water used for common residential properties, which is metered separately.
Table 29 Subiaco - emissions from water and wastewater
SUBIACO Houses/ villas Apartments, Units & Flats Townhouse / Terrace house
9. Precinct comparisons
9.1 Emissions from subdivision works
9.1.1
Landclearing and landscaping
As noted in Section 3.4, the emissions created by land clearing are estimates based on applying the FullCAM process to historical aerial imagery in the case of the greenfield precincts. In the case of Nollamara, the clearing relates to the conversion of large residential lots with trees to subdivided lots with high levels of site coverage for dwellings, driveways, and carports/garages. The differences between the precincts relate to variations in the nature of the cleared vegetation
The emissions created by the loss of vegetation due to land clearing are offset by the subsequent planting as part of landscaping works in streetscapes and parks, represented here as negative emissions. In all cases except Ellenbrook, the on-lot vegetation is minimal and has been ignored. In Ellenbrook, most lots have open areas, and the emissions sequestered by those have been included in the analysis.
The emissions created by the loss and subsequent gain of vegetation are set out in Figure 28, expressed as tonnes of CO2 equivalent per dwelling over 50 years. As can be seen, the emissions created by land clearing of the entire development areas are only partially offset by subsequent plantings on only a portion of the developed land.
It is to be noted that the planting and maintenance of lawn areas, either in residential lots (including verge), reservations and especially sports ovals are GHG positive. In other words, they emit more CO2e than they capture. While it is true that in the planting and initial growing stage they do sequester some GHGs. However, when watering, fertilisation and mowing over a period of 50 years is taken into account the grassed areas are found to emit GHG emissions.
Figure 28 Emissions from land clearing and planting (per dwelling).
9.1.2 Construction
The emissions created during the subdivision process of site formation have been derived from the previous Cerclos report, which examined three developments, namely residential projects Bushmead and 115 Hamilton Hill, and the industrial project of Orion. The component of the Cerclos calculations relating to construction per m2 (i.e. Products, Transport of materials and equipment and Construction) have been calculated and that has been applied to the precincts in this study. The Bushmead project has higher construction emissions than the other projects due mainly to the fill required to develop the site because of the shallow depth of groundwater. The Southern River and Ellenbrook precincts have similar shallow depths to groundwater, so a similar construction effort for the Bushmead project has been assumed. It has also been assumed that the Jindalee development construction effort was more like the Orion and 115 Hamilton Hill projects and an average per m2 values from those projects have been used for Jindalee. Figure 30 illustrates the results on both a per m2 and dwelling basis and identifies the additional emissions created by developing lower-lying areas of Perth.
Figure 29 Both the Ellenbrook and Gosnells precincts are in geomorphic wetlands with typically shallow depth to groundwater.
9.2 Emissions embodied in built form
The Cerclos benchmark LCA of average WA residential dwellings (from a sample of 10) was used to evaluate the emissions created from the Construction phase (i.e. Products, Transport of equipment and materials) plus Replacements of the dwelling on a per m2 Gross Floor Area (GFA) basis. This was then applied to each of the conventional housing typologies in each precinct. The Cerclos benchmarks for 4, 6 and 20-storey multi-residential buildings (per m2 GFA) were averaged and used to determine the Subiaco apartment emissions.
The results are depicted in Figure 31, which shows that embodied emissions largely reflect GFA, noting that emissions are somewhat higher per m2 for apartment buildings with higher emissions intensive construction materials such as concrete and steel in the structural elements of the buildings.
Figure 30 Emissions from subdivision works.
Figure 31 Built form embodied emissions
9.3 Operational emissions
9.3.1
Energy
The expected operational energy and emissions were calculated for each typology in each precinct, assuming a current 7-star NCC benchmark performance for premises. Separate calculations were made for electricity-only houses and electricity-plus-gas houses. The average for each typology was compared with the Western Power and ATCO data received for each of the suburbs most closely related to the precincts. The ATCO data provided the percentage of houses with gas. The 7-star estimates were adjusted on a pro-rata basis with the suburb-level data to provide an estimate of operational emissions associated with electricity and gas use in each typology.
The results are depicted in Figure 32, which illustrates that emissions are largely a function of GFA, noting, however, that emissions per m2 GFA are higher than other housing types (according to the NCC benchmark assumptions).
32 Built from operational energy-related emissions.
9.3.2
Water and wastewater
Emissions associated with the use of water and wastewater services provided by the Water Corporation were calculated from the data received from Water Corporation for water use, and the energy per kL of water and wastewater, and emissions per unit energy, obtained from the 2023 Water Corporation Annual Report. The water use data was aggregated according to the categories used by the Water Corporation, namely Houses/villas, Apartments, Units & Flats, and Townhouse / Terrace houses. Many multi-residential developments have single-metered connections (categorised as Common – residential). This water use was distributed to the Apartments, Units, & Flats category. Wastewater was estimated as a percentage of water use, which is lower for the houses category where external water use is highest.
The results are depicted in Figure 33 on a per-dwelling basis, which illustrates that emissions from water and wastewater are only around 10% of those for operational energy use. Emissions are lower for the smaller premises in Nollamara and Subiaco while somewhat higher for multi-residential dwellings in Ellenbrook.
Figure
9.3.3 Vehicles
The STEM modelling results (Table 30) for each precinct were used to estimate the emissions created by private car use. The VKT figures for all trips “produced” by private car use by the occupants of the precinct were calculated on a per dwelling per annum basis, using data provided for each of the transport zones by DPLH, noting that the precincts are a subset of the areas in each transport zone. The emissions intensity (i.e. gCO2e per VKT) of an average private car was provided by DoT (211 gCO2e/km)
Table 30 Private vehicle emissions
The results are depicted in Figure 34 in relation to the road travel distance from the precinct to the Perth Central Business District.
Figure 33 Emissions from water and wastewater services.
9.4
Precinct summaries
The results above have been used to establish the approximate 50-year emissions per dwelling associated with each precinct. The results are summarised in Table 31 and graphically in Figure 35 The same data is illustrated as cumulative emissions over time in Figure 36 to Figure 40
Table 31 Summary of precinct emissions per dwelling
Figure 34 Private vehicle emissions
Figure 35 Cumulative 50- year precinct emissions per dwelling.
The differences between the precinct emissions per dwelling can be summarised as follows.
Subdivision works
• The emissions from subdivision works in greenfield developments are a significant fraction of lifecycle emissions.
• Development in lower-lying areas (Southern River and Ellenbrook) leads to significantly higher emissions than the other greenfield precinct (Jindalee).
• Avoiding subdivision works in infill precincts (Nollamara and Subiaco) eliminates this source of emissions.
Built form embodied energy
• The precincts with smaller built-form GFAs have lower embodied energy in the built form.
• The background infill and Transit Oriented Development precincts have lower built-form embodied emissions than the greenfield precincts.
Built form operational
• Higher-density areas, such as the Subiaco, can still have comparatively high operational emissions compared to lower-density background infill and even some examples of compact suburbs.
Transport
• The private car emissions are roughly correlated with distance to the Perth CBD for the precincts. Subiaco has the dual advantage of being close to the CBD while also having local jobs and services.
Vegetation
• The relative impact of land clearing and landscaping on emissions is minor relevant to other categories across the precincts.
Water and wastewater
• The indirect emissions associated with water and wastewater are minor compared to other emissions sources. Nonetheless, the suburban precinct with larger lots (Ellenbrook) had higher water use than the compact suburb and infill precincts.
Figure 36 Jindalee - cumulative emissions
Figure 37 Southern River - cumulative emissions
Figure 38 Ellenbrook - cumulative emissions
Figure 39 Nollamara - cumulative emissions
Figure 40 Subiaco - cumulative emissions
10. Typology comparisons
10.1 Location
Vehicle emissions
The location of the precincts and the local availability of jobs and services determines the level of emissions from private vehicle transport.
Subdivision emissions
Location is also a factor in the emissions associated with greenfield subdivision construction. As new development has moved east in the Perth metropolitan area into locations with lower depth to groundwater and associated soil types, fill (and, in some cases, sub-soil drainage) is required. This effect is illustrated in Figure 30
Obviously, urban infill creates no additional emissions associated with subdivision works. However, it is noted that the redevelopment of Subiaco some areas (e.g. Australian Fine China site) would have required significant removal of contaminated soils and there was also some provision of new/ upgraded service infrastructure which is not captured in this analysis.
Operational emissions
Development nearer the coast will also lead to lower average summer air temperatures (see Figure 41). This will impact air conditioning energy/emissions, but it is impossible to disaggregate from the results reported here. The influence of stronger summer coastal sea breezes on the natural ventilation of houses can also not be identified.
10.2 Urban and built form
Dwelling size
The main effects of urban form identifiable from this analysis on emissions relate to the size of lots/dwellings. Irrespective of the built-form construction materials, the GFA has the most dominant impact on embodied (Figure 31) and operational emissions (Figure 32).
Figure 41 Locational summer temperature variations
Urban Heat Island
The analysis described in this report cannot account quantitatively for the impact of Urban Heat Island (UHI). However, it is noted that the similar urban form in Jindalee and Southern River, which have high levels of site coverage (i.e. hard surfaces as a fraction of lot size) and low levels of tree canopy, will raise local temperatures and increase air-conditioning load/emissions.
Rooftop solar PV
All the precincts studied have a high penetration of rooftop solar, providing between 29 and 37% of the average dwelling’s electricity. This has significantly reduced the average electricity consumption/emissions (see Figure 42).
Nearly all houses sampled in each precinct were constructed with the same materials, namely concrete for floor slabs, cavity brick walls and steel or tile roofs. The apartment buildings in Subiaco are also concrete frame buildings 9. Concrete, steel and brick are all high embodied energy materials that contribute significantly to the emissions in each precinct.
9 Assumed, noting that the building permit samples for these buildings are yet to be obtained.
Figure 42 Impact of rooftop solar
Form of construction
11. Next steps
The project's next phase will build on the analysis presented here to develop a conceptual model of energy and emissions in residential suburbs. The key elements of the model will reflect the impact on energy /emissions of the following.
Urban form Tree canopy cover in private and public spaces
Lot shape and site coverage
Density/plot ratio
Built form Built form construction materials
Built from GFA
Weather variations across the metropolitan area
Renewable energy supply
Emissions impact
Subdivision energy /emissions
Operational energy/emissions
Operational energy/emissions
UHI and shading impacts on operational energy/emissions
Impact on natural ventilation contribution to operational energy/emissions
Overall development footprint contribution to subdivision energy/emissions
Embodied energy/emissions
Both embodied and operational energy/emissions.
Operational energy/emissions
Operational energy/emissions
The project team have commenced developing planning interventions for the case study sites as part of the following stage: ‘Step 4 Identify and evaluate potential interventions.’ The initial planning interventions were co-developed with the Department of Planning Lands and Heritage staff at a focus group session on the 31st of January 2024 (see Figure 43). The basic methodology of the focus group design was to ask groups of participants to rank different precinct configurations, street layouts, building types, and open space structures that they believed would most reduce energy use and carbon emissions in their allocated case study. The project team is now interpreting and extrapolating the information gathered into intervention plans for each precinct, which will be subsequently analysed for their impacts on energy/emissions. The results will inform an interesting comparison between what interventions planners think will reduce emissions and what the modelling shows will reduce emissions.
Figure 44 An initial planning intervention for the Nollamara precinct includes coordinated low to medium-rise apartment buildings along a central transit corridor (Nollamara Avenue) and reducing ad-hoc background infill throughout the broader suburban expanse. This intervention is based on feedback from the planning interventions workshop and State Planning Policy 7.2 - Precinct Design.
