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Carbon footprint and embodied energy consumption assessment of building construction works in Western Australia

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The Australian Green Infrastructure Council (AGIC) is currently leading a new approach to the delivering and operating of infrastructure through a more careful examination of the carbon footprint of construction activities. Using a life cycle assessment (LCA) methodology, this paper presents life cycle greenhouse gas (GHG) emissions and energy analysis of the Engineering Pavilion (hereinafter referred to as Building 216), at Curtin University Western Australia. The University utilises a Building Management System (BMS) to reduce its overall operational energy consumption. This LCA analysis employed a ‘mining to use’ approach, in other words, the analysis takes into account all of the stages up to the utilisation stage. The life cycle GHG emissions and embodied energy of Building 216 were calculated to be 14,229 tonne CO2-e and 172 TJ, respectively. This paper identified the ‘hotspots’, or the stages in production and operation of Building 216 that were the cause of the majority of the GHG emissions. From this, proposals for further improvements in environmental management may be made. The usage stage of the building produces 63% less GHG emissions than the University average, due to the implementation of the BMS. This system has played a significant role in reducing the total embodied energy consumption of the building (i.e., 20% less than the University average).
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1
2Original Article/Research
3Carbon footprint and embodied energy consumption assessment
4of building construction works in Western Australia
Q1
5Wahidul Karim Biswas
Q2
6Sustainable Engineering Group, Curtin University, Perth, Australia
7Received 20 March 2014; accepted 11 November 2014
8
9Abstract
10 The Australian Green Infrastructure Council (AGIC) is currently leading a new approach to the delivering and operating of infra-
11 structure through a more careful examination of the carbon footprint of construction activities. Using a life cycle assessment (LCA)
12 methodology, this paper presents life cycle greenhouse gas (GHG) emissions and energy analysis of the Engineering Pavilion (hereinafter
13 referred to as Building 216), at Curtin University Western Australia. The University utilises a Building Management System (BMS) to
14 reduce its overall operational energy consumption.
15 This LCA analysis employed a ‘mining to use’ approach, in other words, the analysis takes into account all of the stages up to the
16 utilisation stage. The life cycle GHG emissions and embodied energy of Building 216 were calculated to be 14,229 tonne CO
2
-e and
17 172 TJ, respectively. This paper identified the ‘hotspots’, or the stages in production and operation of Building 216 that were the cause
18 of the majority of the GHG emissions. From this, proposals for further improvements in environmental management may be made. The
19 usage stage of the building produces 63% less GHG emissions than the University average, due to the implementation of the BMS. This
20 system has played a significant role in reducing the total embodied energy consumption of the building (i.e., 20% less than the University
21 average).
22 Ó2014 The Gulf Organisation for Research and Development. Production and hosting by Elsevier B.V. All rights reserved.
23
24 Keywords: LCA; Building; BMS; GHG emissions; Embodied energy
25
26 1. Introduction
27 In general, buildings contribute approximately 30% to
28 total global GHG emissions (UNEP, 2009). In efforts to
29 reduce global warming, GHG reductions in this area would
30 make a significant contribution (UNEP, 2009). According
31 to the Intergovernmental Panel on Climate Change
32 (IPCC), there are three areas to focus on in reducing
33emissions from buildings: reducing energy consumption
34and building embodied energy, switching to renewable
35energy, and controlling non CO
2
emissions (Levine and
36Urge-Vorsatz, 2007)Q3. In Australia, regulation is already
37reshaping the built environment, with mandatory disclo-
38sure of the National Australian Built Environment Rating
39System driving higher levels of energy efficiency in commer-
40cial buildings. The carbon price also encouraged more
41informed decision-making across the economy (GBCA,
422013), although this is no longer the case due to change
43in government in 2013.
http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
2212-6090/Ó2014 The Gulf Organisation for Research and Development. Production and hosting by Elsevier B.V. All rights reserved.
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and Development.
International Journal of Sustainable Built Environment (2014) xxx, xxxxxx
HOSTED BY
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IJSBE 62 No. of Pages 8
20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
Western Australia
Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
44 Australia’s per capita greenhouse gas emissions are the
45 highest of any OECD country and are among the highest
46 in the world (Garnaut, 2008). The nation’s built environ-
47 ment is experiencing enormous pressure due to its popula-
48 tion increase, economic growth, and the government’s
49 existing energy and environmental policies (Department
50 of Environment, 2011). Almost a quarter (23%) of Austra-
51 lia’s total GHG emissions are the result of the energy
52 demand from the building sector (Department of
53 Environment, 2009). The building sector, comprising resi-
54 dential and commercial buildings, drives a large proportion
55 of Australia’s economic activity (Electrical Solutions,
56 2008). The building sector’s contribution to GHG emis-
57 sions is mainly driven by its end use of, or demand for, elec-
58 tricity (operational energy). For example, there are
59 approximately 21 million square metres of commercial
60 office space in Australia, spread across 3980 buildings
61 (The Parliament of the Commonwealth of Australia,
62 2010). However, in the main, these offices have not been
63 designed to consider energy efficiency or solar passive
64 design or their long-term environmental and social impact
65 (Department of Climate Change and Energy Efficiency,
66 2012; Property Council of Australia, 2008).
67 Along with GHG emissions, energy consumption is
68 often used to measure the environmental performance of
69 buildings. Recent studies have highlighted the importance
70 of both embodied energy and operational energy use attrib-
71 utable to buildings over their lifetime (Biswas et al., 2008).
72 Embodied energy is the energy consumed by processes
73 associated with the total production of a building, from
74 the acquisition of natural resources from processes includ-
75 ing mining and manufacturing, through transport and
76 other functions, and finally, the operational energy, involv-
77 ing the energy utilised by the building’s operations and use
78 (air conditioning, heating and lighting, office and kitchen
79 equipment).
80 The building industry has now acknowledged its envi-
81 ronmental shortcomings, and through the Australian
82 Green Infrastructure Council (AGIC) will lead a new
83 approach to the delivering and operating of infrastructure
84 by undertaking a more detailed examination of the carbon
85 footprint (the total sets of greenhouse gas emissions caused
86 by product life cycle stages) associated with construction
87 activities.
88 Life cycle assessment (LCA) for green building design
89 has recently been developed around the understanding that
90 there is a shortage of holistic environmental assessment
91 tools in the building industry (Horne et al., 2009). The life
92 cycle assessment brings benefits to the decision-making
93 process in that it can be used to review sustainability initia-
94 tives throughout the entire life cycle of the building, includ-
95 ing the design, detailing, delivery and deconstruction
96 phases. A number of studies in North America, Europe
97 and Japan have used LCA as a useful tool for determining
98 the carbon footprint and embodied energy consumption in
99 assessing the environmental performance of buildings
100 (Lemay, 2011; Bribia
´n et al., 2009; Junnila and Horvath,
1012003; Junnila et al., 2006; Suzuki and Oka, 1998). In
1022000, Fay et al., applied the LCA in evaluating alternative
103design strategies for an energy efficient Australian residen-
104tial building. Since then, no LCA study has yet been pub-
105lished which assesses the environmental impact from
106modern buildings in the public sector in Australia.
107Energy consumption in Western Australia grew at an
108annualised rate of 6 per cent between 2008 and 2012, faster
109than the average increase across Australia of 1.1 per cent,
110linked to economic growth (CCA, 2013). This paper, thus,
111assessed the embodied energy and associated carbon GHG
112saving benefits of the use of an energy efficient building in
113Western Australia.
114The new Building 216 Engineering Pavilion Complex
115at Curtin University in Western Australia comprises two
116building wings located around an exhibition plaza. Using
117an LCA methodology, this paper presents a life cycle
118GHG emissions and energy analysis of Stage 2 of Building
119216 (Fig. 1). This paper identified the ‘hotspots’, or the
120stages which are the cause of most of the GHG emissions
121from the building construction and operational phases, so
122that further environmental management improvements
123can be made.
1242. Methodology
125Following Biswas (2014), this LCA is best termed as
126streamlinedLCA (SLCA), as it does not take into
127account the recycling of building materials or their disposal
128into landfill. This SLCA that was employed followed the
129ISO14040–44 guidelines (ISO, 2006) in calculating the life
130cycle GHG emissions and embodied energy of Stage 2 of
131Building 216. The LCA is divided into four steps: (1) goal
132and scope definition; (2) inventory analysis; (3) impact
133assessment; and (4) interpretation (as presented in the
134‘Results’ section of this report). This LCA has limited its
135focus to two impact categories only (Finkbeiner et al.,
1362011); global warming impact, or carbon footprint, and
137embodied energy. Finally, this LCA is process-based,
138where the input data, in the form of energy and chemicals
139for each of the processes of the building’s life cycle, has
140been utilised in assessing global warming and embodied
141energy consumption impact.
1422.1. Goal and scope definitions
143The goal of this research is to assess the environmental
144performance of Building 216 in terms of carbon footprint
145and embodied energy consumption. Carbon footprint is
146the total sets of greenhouse gas emissions caused by build-
147ing life cycle stages, including mining, manufacturing,
148transport and the use. In the current analysis, the embodied
149energy includes the energy consumed by processes associ-
150ated with the production of the building, from the acquisi-
151tion of natural resources to final consumption including
152mining, manufacturing, transport and the use of building.
153In this current research, energy consumption associated
2W.K. Biswas / International Journal of Sustainable Built Environment xxx (2014) xxx–xxx
IJSBE 62 No. of Pages 8
20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
Western Australia
Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
154 with the demolition and transportation to landfill have not
155 been considered. This LCA is limited to three stages: the
156 supply of construction materials, the construction stage
157 and finally the usage stage.
158 The ‘supply of construction materials’ stage includes the
159 amount of greenhouse gas emissions associated with the
160 mining, processing, and production of construction materi-
161 als (e.g., concrete, steel, glass) along with transportation to
162 the construction site (i.e., Curtin University). The locations
163 for the gathering of the construction materials were advised
164 by the Curtin University Project Management Department.
165 The ‘construction stage’ includes the GHG emissions
166 associated with the construction process, including fencing,
167 site-clearing, excavation and filling, installation of a tower
168 crane, concrete pouring, pre-casting, shuttering and mortar
169 preparation.
170 The ‘usage stage’ includes the GHG emissions associated
171 with the energy consumption of end use appliances within
172 the building, including lighting, computing, office and
173 kitchen equipment, air conditioning, lifts, fans and heating.
174 The duration of the usage stage’ of the building was
175 assumed at 50 years, and the end use energy consumption
176 pattern has been considered to remain the same during this
177 period. An increase in cooling load due to climatic change
178 was also taken into account in order to determine the
179 future energy consumption of the air conditioning system
180 (Guan, 2009).
181 This LCA analysis identified the stages causing the most
182 significant greenhouse emissions, the inputs (energy or
183 materials) creating the largest carbon footprints (measured
184 as weight of CO
2
-e) and the production activities with the
185 most embodied energy.
186 2.2. Inventory analysis
187 A life cycle inventory considers the amount of each
188 input and output for processes which occur during the life
189 cycle of a product. Undertaking a life cycle inventory is a
190 necessary initial step in carrying out an LCA analysis.
191The inputs in terms of energy and material for Building
192216 were obtained from the Curtin University Project
193Management Department.
194The total amount of construction materials was esti-
195mated for the construction of the building. The building
196materials inventory was conducted in accordance with given
197schematic design drawings. Every item was calculated dis-
198cretely and classified according to its base material, such
199as concrete or steel or glass. In the case of insufficient data,
200standard material specifications were assumed after con-
201sulting with the project architect. Since the estimation was
202based on schematic designs, the type and amount of mate-
203rials which were finally selected showed some variation.
204Tables 1–3 show the amount and sources of construc-
205tion materials, energy consumption in construction, and
206end use applications, respectively. Electrical energy is
207mainly used for construction purposes and end use applica-
208tions. Diesel engines were used for transportation, crane
209and mortar operations during the construction stage.
210Along with greenhouse gas emissions from electricity gen-
211eration, and the combustion of diesel during the transpor-
212tation, construction and usage stages, greenhouse gas
213emissions from other processes associated with the produc-
214tion of these inputs or construction materials (e.g., con-
215crete, steel, glass, aluminium) were also included. Table 3
216provides the data for calculating energy consumption over
21750 year usage period.
218All these inputs, including the energy and construction
219materials highlighted above were used to calculate the total
220GHG emissions associated with the life cycle of the produc-
221tion and use of Building 216.
2222.3. Impact assessment
223The greenhouse gas emissions assessment of the produc-
224tion and use of this building involves two steps. The first
225step calculates the total gases produced in each process,
226and the second step converts these gases to a CO
2
-equiva-
227lent (CO
2
-e).
Fig. 1. Building 216.
W.K. Biswas / International Journal of Sustainable Built Environment xxx (2014) xxx–xxx 3
IJSBE 62 No. of Pages 8
20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
Western Australia
Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
228Step 1: The input (i.e., construction materials and
229energy) data in the life cycle inventory were put into the
230Simapro 7.2 (PRe
´Consultants, 2011) software to ascertain
231the greenhouse emissions associated with the production
232and use of the new building. The recorded units of input
233and output data from the life cycle inventory depend on
234the prescribed units of the relevant materials in Simapro
235or its libraries (PRe
´Consultants, 2011).
236In order to make the LCA results more representative of
237Australian conditions, local databases and libraries were
Table 1
Amount and sources of different construction materials.
Materials Location Distance (km) Amount Unit (tkm)
Bricks (midland bricks) Midland 25 27.3 m
3
1251.3
Concrete Precast Madington 15 362.5 m
3
13050.0
Concrete Readymix Welshpool 8 1844.3 m
3
35409.8
Cement (for mortar) 10 2.0 m
3
35.8
Sand (for mortar) 10 5.98 m
3
107.64
Steel Structural (one steel) Bibra lake 22 84.7 tonne 1863.3
Steel Reinforcing (one steel) Forrestfield 15 58.9 m
3
6982.0
Window frame + glass Wangara 37 1932.8 m
2
185.9
Door frame + glass Wangara 37 75.0 m
2
7.2
Other glass Wangara 37 18.9 m
2
1.8
Metal roof cover Madington 14 399.6 m
3
13426.6
Drainage gutter Madington 14 23.3 m
3
782.208
Trafficable grating 15 2580 m
2
38.7
Ceiling suspension system Welshpool 10 32,440 m
2
m
2
Paints + accessories Osbourne park 17 m
2
m
2
53.6
Carpet + relevant accessories Osbourne park 17 3593 m
2
73.3
Vinyl floor Osbourne park 17 330 m
2
28.0
Tiles Osbourne park 17 383 m
2
84.6
Plasterboard (Boral) Canning vale 12 182 m
2
21.8
Insulation (Boral) Canning vale 12 m
2
m
2
792.2
Timber-cladding Osbourne park 17 1.0 m
2
12.6
Timber-doors Osbourne park 17 4.5 m
2
57.9
PVC pipe Osbourne park 17 320.0 m 1.3
Notes: Distances assumed as the nearest available supplier/retailer from Curtin University.
Actual location of manufacturing factory may vary. ‘tkm’ means that a km travelled to carry a tonne of construction material.
Table 2
Energy consumption during the construction stage.
Main activities Sub-activities Total
power
Unit
Builders moving to
site
Diesel for transportation 12 Litre
Crane operation 206,000 kWh
Computers (200 watt) 1500 kWh
Printer (350 watt) 175 kWh
Air conditioner (1000 watt) 5000 kWh
Telephone (10 watt) 25 kWh
Lighting (100 watt) 2,500 kWh
Fencing around the
site
Fences 24 Litre
Tree chipper 240 Litre
Site clearing Transfer/removal of green
waste
250 Litre
Levelling 500 Litre
Excavation and
filling
Diesel for transportation 12 Litre
Operation of excavator 1000 Litre
Installing tower
crane
Installation by crane 1030 kWh
Operation 38,250 kWh
Concrete pouring Diesel for Ready mix truck 1456 Litres
Concrete pump 59 Litres
Operation 7175 kWh
Precast concrete Diesel for transporting
materials
102 Litre
6180 kWh
Mortar preparation Diesel for transport 12 Litres
Operation 8250 kWh
Waste removal 48 Litre
Table 3
End-use energy consumption by different end-use appliances.
Appliances Number of
appliances/area
Avg. operating
hour/day
Capacity
Lighting 500 7.75 12 W
Computer desktop 188 12 190 W
Computer laptop 120 4 17 W
Projector 16 6.5 325 W
Photocopier 5 3 3500 W
Printer 20 1 387.5 W
Fax machine 2 0.5 20 W
Telephone 60 0.5 10 W
Microwave oven 6 1 1500 W
Refrigerator 3 24 400 W
Coffee maker 2 1 1000 W
Lift 1 8
Air conditioning 3495 m
2
10 41.2 kW
Heating/cooling 1.4 kW
Fan 7 kW
Note: In the case of air conditioner, the variable air volume (VAV) system,
is connected to Curtin’s central air conditioning system.
4W.K. Biswas / International Journal of Sustainable Built Environment xxx (2014) xxx–xxx
IJSBE 62 No. of Pages 8
20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
Western Australia
Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
238 used. In the absence of Australian databases, European
239 databases were included to carry out the analysis.
240 The Australian LCA database (RMIT, 2007) was the
241 library used for construction materials information in
242 order to calculate greenhouse gas emissions from the pro-
243 duction of construction materials, such as aluminium, steel,
244 concrete, and glass. The emissions factors for plaster
245 board, paint and floor covers were obtained from the Euro-
246 pean database (Frischknecht et al., 1996), as Australian
247 databases or libraries were unavailable (RMIT, 2007).
248 The library for the supply chain of construction materi-
249 als to the point of use, was incorporated in order to assess
250 the greenhouse gas emissions arising from the transporta-
251 tion of materials to the site. The unit for the transport
252 library is tonne-kilometre (tkm). For example, 1863 tkm
253 is required to carry 84.7 tonne kg of structural steel from
254 Bibra Lake, which is 22 km away from the construction site
255 (84.7 tonne 22 km).
256 The library for Western Australian electricity generation
257 was used to calculate the greenhouse gas emissions associ-
258 ated with the electric power used in the construction pro-
259 cess (RMIT, 2007). In addition, the Australian database
260 for diesel combustion was used to calculate the GHG emis-
261 sions from crane and mortar operations (RMIT, 2007).
262 Step 2: Simapro 7.2 software calculated the greenhouse
263 gas emissions, following the linking of the inputs and out-
264 puts to the relevant libraries. The programme sorted green-
265 house gas emissions from the selected libraries, and then
266 converted each selected greenhouse gas to CO
2
-e. The Aus-
267 tralian Greenhouse Gas method, developed by RMIT
268 (RMIT, 2007), was used to assess the GHG emissions.
269 The Cumulative Energy Demand Method was used to
270 determine the embodied energy within the engineering
271 building. Simapro software developed the process networks
272 for determining the breakdown of GHG emissions and
273 embodied energy from the production and use of Building
274 216.
275 3. Limitations
276 Foreign databases for some construction materials were
277 used, due to the absence of local library information on
278 these materials. Emission factors for plaster board, floor
279 coverings and paint were obtained from the Eco-invent
280 database, which is based on European production and
281 energy sources. This may affect the accuracy of the LCA
282 estimates provided.
283 4. Results and discussion
284 4.1. Carbon footprint analysis
285 Q4 The Life cycle GHG emissions and the embodied energy
286 assessment of Building 216 considered a total building
287 weight of 5633 tonnes and a gross area of 4020 m
2
. The car-
288 bon footprint, including GHG emissions from the mining,
289 construction and usage stages of the new building was 14,
290229 tonnes CO
2
-e (Table 4). The usage stage’ produced a
291carbon footprint of 12,145 tonne CO
2
-e, representing about
29285% of the total life cycle GHG emissions. This is approx-
293imately seven times more carbon intensive than the supply
294of construction materials stage’ (1778 tonne CO
2
-e and 13%
295of total emissions), and 40 times more carbon intensive
296than the construction stage’ (2% of total emissions) of
297the new building.
298Whilst the usage stage’ could contribute 0.06 tonne
299CO
2
-e per m
2
per year during the 50 year life of the build-
300ing, it is 63% lower than the University building usage
301stage’ average (i.e., 0.16 tonne CO
2
-e) (Australian
302Government, 2009) due to the utilisation of an energy effi-
303cient Building Management System (BMS). The BMS has a
304computer based control system to monitor and control the
305automatic cooling of the air throughout the building to
306achieve the desired ambient temperature (i.e., 25 °C). The
307BMS operates the air conditioning system only when the
308inside temperature exceeds 25 °C.
309Ngo et al. (2009) estimated that the GHG emissions
310associated with the production and supply of materials,
311construction and use stages of a typical Australian com-
312mercial building using no BMS was around 9.1 tonnes of
313CO
2
-e/m
2
. The percentage saving of GHG emissions has
314been estimated to be about 60% associated with the
315replacement of a traditional commercial building with a
316building like Curtin Engineering Pavilion.
317Fig. 2 shows the GHG contributions of all end-use
318appliances during the usage stage’. The cooling load
319(68.8%), lifts (15.0%) and fans (9.6%) are the major electric-
320ity consuming appliances and contribute more than 93% of
321the total emissions during the usage stage’. Since the cool-
322ing load accounts for a significant proportion of the total
323energy consumption during the usage stage’(Fig. 2), a
324reduction in the cooling load could decrease the life cycle
325GHG emissions significantly. Amenity utilities (i.e., office
326and kitchen appliances) like coffee machines, printers, pro-
327jectors, telephones and microwave-ovens contribute a small
328portion 3%) of the total GHG emissions. Although refrig-
329erators are a base load appliance, they account for only
3301.3% of the total GHG emissions.
331When supply of construction materials and construction
332stages were combined, it appeared that concrete accounted
333for a significant proportion (42%) of total emissions, from
334the mining to material production sub-stage (Fig. 3). How-
335ever, the emissions from concrete on a per unit weight basis
Table 4
Carbon footprint and embodied energy consumption of a new Engineer-
ing Pavilion (Building 216).
Stages Carbon footprint tonnes
of CO
2
-e
Embodied
energy TJ
Supply of construction
materials
1778 19
Construction stage’ 306 3
Usage stage 12,145 150
Total 14,229 172
W.K. Biswas / International Journal of Sustainable Built Environment xxx (2014) xxx–xxx 5
IJSBE 62 No. of Pages 8
20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
Western Australia
Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
336 (0.14 tonne of CO
2
e-per tonne of concrete) were signifi-
337 cantly lower than for aluminium (19 tonne of CO
2
e-per
338 tonne of aluminium). This is due to the higher energy
339 requirements in converting alumina to aluminium.
340 Transport constitutes only 0.53% of the total GHG
341 emissions in the mining to building construction stage’
342 (i.e., 2083 tonnes of CO
2
-e)Q5 . The construction sub-stage,
343using diesel fuel for crane and mortar operation purposes
344(i.e., 305 tonne of CO
2
-e), produces around 6 times less
345GHG emissions than the mining to material production
346sub-stage (i.e., 1767 tonne of CO
2
-e).
3474.2. Embodied energy analysis
348The total life cycle embodied energy of Building 216,
349with a projected 50-year life cycle is 172 TJ (terajoules)
350(Table 4), which is 20% less than the University’s annual
351building energy consumption (215.4 TJ) (Australian
352Government, 2009), indicating the significant thermal com-
353fort performance improvement of Building 216 (NDY
354Consulting Ltd., 2010). The usage stage accounts for
35587% of the embodied energy in Building 216, with the sup-
356ply of construction materials generating 11%, and the con-
357struction stage 2%. The energy consumption of the usage
358stage is 6.8 times higher than the energy consumption asso-
359ciated with actually constructing Building 216 (including
360the mining, processing, transportation and application of
361construction materials). The specific energy consumption
362of the usage stage is 0.75 GJ per m
2
per year, as opposed
363to 0.92 GJ per m
2
per year for the University building
364average.
365Fig. 4 shows the contribution of embodied energy for
366different end use appliances as a percentage of the total
367embodied energy for the use stage. Electricity for thermal
368applications alone, including heating and cooling alone,
369account for 80% of the total embodied energy, followed
370by lifts (16%). Central lighting accounted for only 1 per
371cent of the total energy, as the building has been designed
372to receive more sunlight in order to avoid the need for
373lighting during the day, and all lamps used in this building
374are equipped with energy saving globes. The embodied
Fig. 2. Percentage contribution of inputs to GHG emissions during the
’Usage stage’.
Fig. 3. GHG emissions from mining to production of construction
materials.
Fig. 4. Embodied energy consumption for different end use appliances.
6W.K. Biswas / International Journal of Sustainable Built Environment xxx (2014) xxx–xxx
IJSBE 62 No. of Pages 8
20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
Western Australia
Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
375 energy associated with class rooms (i.e., computers, over-
376 head projectors), offices (telephones, photocopiers, fax
377 machines and printers), and kitchen appliances (i.e.,
378 micro-wave ovens, coffee machine) accounted for around
379 3% of the total energy consumption during the usage stage.
380 The embodied energy consumption of the mining to
381 material production, transportation and construction
382 sub-stages contributes 18 TJ, 0.08 TJ and 3.75 TJ, respec-
383 tively. Although Fig. 5 shows that concrete has the highest
384 share of the total GHG emissions, followed by aluminium;
385 in the case of embodied energy it is reversed, with alumin-
386 ium having the highest share (i.e., 39%) followed by con-
387 crete (i.e., 31%). This is because the production of
388 aluminium requires about 200 times more energy than
389 the production of concrete, and as a result GHG emissions
390 from aluminium production are 19 times higher than those
391 from concrete production (RMIT, 2007).
392 4.3. GHG emissions mitigation using cleaner production
393 strategies
394 Whilst the usage stage contributes the largest portion of
395 both GHG emissions and embodied energy consumption,
396 there are no opportunities, other than using renewable
397 energy, for improving the energy performance of the build-
398 ing. This is because this new building has implemented the
399 Building Management System along with modern electrical
400 equipment. It was therefore, seen as worthwhile to examine
401 opportunities to reduce the environmental impact of mate-
402 rial production on a life cycle basis. In addition, given the
403 high energy intensities involved in the manufacture of
404 concrete and aluminium, a number of areas could be
405 further investigated in order to enhance the environmental
406 performance of building construction materials.
407Research has highlighted the benefits of the following
408mitigation strategies in reducing the carbon footprint of a
409new building like Building 216 including:
4101. The replacement of 30% by weight of cement with
411fly ash in concrete formulations (Nath, 2010).
4122. The substitution of new aluminium with recycled
413aluminium, reducing GHG emissions by around
41470% (Damgaard et al., 2009).
4153. The substitution of new steel with recycled steel,
416reducing GHG emissions by around 60%
417(Damgaard et al., 2009).
418
419
Assuming the above substitutions can be made with
420functional equivalence between the alternative materials,
421it was estimated that 47% of the total GHG emissions in
422the mining to material production stage can potentially
423be avoided by replacing 30% of cement with fly ash, new
424aluminium with recycled aluminium and new steel with
425recycled steel. These material substitutions reduced the
426total GHG’s emitted during the ‘cradle to use’ life cycle
427of Building 216 by a further 7% (i.e., 13, 241 kg CO
2
-e).
4285. Conclusions
429Life cycle assessment is increasingly being used to deter-
430mine the environmental impacts of building and construc-
431tion projects. The Life cycle GHG emissions and
432embodied energy of Stage 2 of Building 216 are 14,229
433tonne CO
2
-e and 172 TJ, respectively. The ‘usage stage’ of
434this building produces 63% less GHG emissions than the
435University’s building average, due to the implementation
436of an energy efficient Building Management System. As a
437result of the introduction of this system, embodied energy
438consumption of the life cycle of the building is 20% less than
439the university average. The current research estimated that
440there is a potential for saving around 60% carbon footprint
441associated with the replacement of a traditional conven-
442tional building with this Building 216 in Australia.
443However, opportunities for GHG mitigation still exist in
444the construction and material life cycle of a new building
445with the use of revised cement formulations and recycled
446aluminium and steel where possible. Applying these mitiga-
447tion strategies could further reduce the total life cycle GHG
448emissions of Building 216 by a further 7%.
4496. Uncited references
450(Fay et al., 2000; GBCA, 2008). Q6
451
Acknowledgements
452Engineer PradipNath for inventory development and A/
453Prof Michele Rosano for editorial support. Dr. Odile
454Pouliquen-Young and Architect Charles Boyle for provid-
455ing useful information on university buildings and the
456building plan for the life cycle assessment analysis. Mr John
Fig. 5. Percentage of the total embodied energy of construction materials.
W.K. Biswas / International Journal of Sustainable Built Environment xxx (2014) xxx–xxx 7
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457 Chapman, who was involved in the electrical system design
458 of the building for Engineering Pavilion Stage 2, for provid-
459 ing information on electrical loadings and the Building
460 Management System. Finally, thank you to the Environ-
461 ment and Sustainability Office, Curtin University, Western
462 Australia for funding this project.
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20 November 2014
Please cite this article in press as: Biswas, W.K. Carbon footprint and embodied energy consumption assessment of building construction works in
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Q1 . International Journal of Sustainable Built Environment (2014), http://dx.doi.org/10.1016/j.ijsbe.2014.11.004
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