The estimation of energy consumption and CO2 emission due to housing construction in Japan

The estimation of energy consumption and CO2 emission due to housing construction in Japan

ENE&G¥ AND II ELSEVIER . UILDING$ Energy and Buildings 22 (1995) 165-169 The estimation of energy consumption and CO2 emission due to housing const...

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ENE&G¥ AND

II ELSEVIER

. UILDING$ Energy and Buildings 22 (1995) 165-169

The estimation of energy consumption and CO2 emission due to housing construction in Japan Michiya Suzuki a, Tatsuo Oka b, Kiyoshi Okada b " Technology Division, Shimizu Corporation, Tokyo, Japan b Faculty of Engineerin& Utunomiya University, Tochigi Prefecture, Japan

Received 16 September 1994; accepted in revised form 14 December 1994

Abstract

Basic sector classification Input/Output Tables of Japan (Research Committee of International Trade and Industry, Tokyo, Japan, 1988) were applied to quantify the total energy consumption and CO2 emission including direct and indirect effects due to the construction of various types of houses. As a result, energy consumption for construction is calculated as 8-10 GJ per square meter of floor area for multi-family SRC (steel reinforced concrete) houses, 3 GJ for wooden single-familyhouses, 4.5 GJ for lightweight steel structure single-family houses. CO2 emission resulting from construction is 850, 250 and 400 kg/m2, respectively. Keywords: Japan; Residential buildings; Energy consumption; Carbon dioxide emission

1. Introduction The purpose of this study is to quantify the total amount of energy consumption and CO2 emission caused by the various types of housing construction. In Japan, the construction of houses accounted for a 52% share of construction in terms of the floor area in 1985 [1]. In addition, housing construction consumed 416 000 TJ of energy [2], which was approximately 4% of the total domestic energy consumption of Japan [3]. The construction of houses has an impact on many other industries because of the use of various kinds of materials which are produced in various categories of industry. In order to quantify the energy consumption and CO2 emission, it is necessary to obtain the total amount of domestic goods and services that were used directly and indirectly for house construction (referred to hereafter as total domestic product). For this quantitative analysis, the estimations of the houses are analyzed and then the Input/Output Table of Japan [4] is used for the calculation of the total domestic product. In the current table, the industries in Japan have been classified into approximately 400 groups.

2. Analytical method and houses analyzed Eight houses were analyzed by using the estimated construction price per square meters of floor area as listed in Table 1. Two of them were SRC multi-family 0378-7788/95/$09.50 © 1995 Elsevier Science S.A. All rights reserved

SSDI 0378-7788(95)00914-J

houses, four of them were wooden single-family houses and the rest of them were lightweight steel-framed single-family houses (prefabricated houses). The difference between the price of No. 1 multi-family house and No. 2 is mainly caused by the difference in the subsurface condition of the sites. To calculate the total domestic product using the Input/Output Table, it is necessary to estimate the total demand. First, the construction cost written in the estimate was separated into five categories: temporary work, structural work, finishing work, equipment work and general management cost. The cost of each category was then itemized and classified further into two categories (i) material cost (.which includes the cost of materials and other items and goods purchased from other categories of the industries), (ii) labor cost which includes the labor cost and other value added. The average labor/material cost data corresponding to each work category [5] are used to calculate the required labor cost and material cost of construction. The cost of materials, thus, is the cost to the consumer. It is necessary to subtract transportation cost, storage cost and profitability from the estimation of each house, because the Input/Output Table is based on the cost of the producer. In this paper, the average transportation cost, average storage cost and average profitability written in the table are used and subtracted from the price of the buyer to obtain the total demand.

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M. Suzuki et al. / Energy and Buildings 22 (1995) 165-169

Table 1 Analyzed houses S R C multi-family house

Wooden single-family house

No. I

No. 2

No. 1

No.2

No. 3

No. 4

No. 1

No. 2

Total floor area (m 2) Number of storys Structure

10339 20, B1

5425 12

119 2

134 2

140 2

120 2

138 2

155 2

Estimate (yen/m z)

176000

steel reinforced concrete

Lightweight steel-structure single-family house

wooden ~amed (Japanese style)

367000

170000

lightweight steel ~amed

2× 4

164000

165000

163000

192000

193000

Multi-family - 1 Multi-family - 2 E Wooden - 1



General expenditure

Wooden- 2 ~ ! [ ] Equipmentwork Wooden - 3



Finishing work

Wooden- 4 [ ] Structuralwork

Light-weight steel - 1 Light-weight steel - 2 0

20

40

60

80

100

120

140

160

Fig. 1. Material cost for construction of house (1000 yen/m:).

The cost for general management was estimated by analyzing the financial statement of four representative house makers in Japan. In this paper, general management cost was divided into many sub-categories such as mail and telegram costs, advertising expenses and office supplies by using the statistic data [6]. Finally, each cost was converted to reflect the cost in 1985 by using the Construction Price Deflator for 1985. The calculated and revised costs for materials are divided by corresponding floor area of the house (as shown in Fig. 1). Material cost per square meter of floor area is 130 000-155 000 yen for multi-family houses, approximately 70 000 yen for wooden single-family houses and approximately 95 000 yen for lightweight steel-framed single-family houses. The material cost of temporary work and structural work is low in single-family houses compared with that of multi-family houses.

3. Calculation of total domestic product The Leontief inverse matrix was used to estimate the total domestic product and the calculation method was applied as mentioned in Section 2. The model for calculating the total domestic product is the following

expression: X = [ ( I - (I - M ) A ) ] - l [ ( I

--M)Y+E]

where X = production vector=total domestic product (yen/year/m:), I = unit matrix, h = coefficient of input matrix.

[mi ml M i = import of i product (yen/year/square meters)

M, m i = n i c i = E h i y X j + Yi J

C~= (domestic product + import-export) of i product (yen/year/ma), Y=total demand vector (yen/year/m2), E = export vector (yen/year/mE). The total domestic product (X) is separated into five categories of work (as shown in Table 2). The difference between multi-family house No. 1 and No. 2 is caused by the structural work. No. 1 uses approximately twice as much steel and concrete for the sub-structure and piling work because of its shape and the condition of the sub-surface.

M. Suzuki et al. / Energy and Buildings 22 (1995) 165-169

167

Table 2 Total domestic product (Unit: 1000 yen/m2)

Temporary work Structural work Finishing work Equipment work General expenditure Value added Total

Lightweight steelstructure singlefamily house

SRC multi-family house

Wooden single-family house

No. 1

No. 2

No. 1

No. 2

No. 3

No. 4

No. 1

No. 2

38 96 74 42 20 130 347

32 138 74 62 17 149 426

3 29 51 29 20 89 201

3 27 39 34 16 64 175

2 31 41 42 18 91 196

3 25 40 45 18 70 198

3 20 96 51 22 78 265

3 23 87 47 21 82 258

The amount of total domestic product is 350 000--430 000 yen per square meter for SRC multifamily houses, 175 0 ( 0 2 0 0 000 yen per square meter for wooden single-family houses and approximately 260 000 yen per square meter for lightweight steelframed single-family houses. The total domestic products for SRC multi-family houses are twice as much as that for wooden single-family houses.

4. Total amount of resource and energy consumption Table 3 shows the amount of major materials which results in the energy consumption and CO2 emission. The raw materials in different categories were calculated by using the Table of Materials of the Input/ Output Table. Iron ore and limestone are mainly used for structural work. City gas is used for various kinds of industrial heating processes. Wood is used for finishing and structure. Other materials such as glass and plastics do not appear in this table. However energy resources used for the production of these kinds of materials have been calculated and added to each

category of energy resources such as coal, oil, city gas and so on. The amount of energy consumption was calculated by using the amount of coal, oil, naphtha, LPG, coke, electric power and city gas listed in Table 3, Fig. 2 shows the energy consumption required for house construction. Energy consumption for the construction is 8-10 GJ per m 2 of floor area for multifamily SRC houses, 3 GJ for wooden single-family houses and 4.5 GJ for lightweight steel-structure singlefamily houses. It is reported that the energy consumption for the construction of a typical Danish single-family house is 4.5 GJ per m 2 of floor area which is calculated using the Danish Input/Output Table [7]. Energy consumption for the construction of a Japanese wooden single-family house is 2/3 of that for a Danish singlefamily house. The major reason seems to be the use of wood for the structure and in some finishing. The energy consumption for the construction of SRC multifamily houses is about three times more than that for wooden houses. Energy consumption for structural work for wooden single-family houses is only 11% of that for multi-family houses.

Table 3 Major resources required for house construction per m 2

Lime stone (kg) Coal (kg) Oil (!) Naphtha (1) LPG (kg) Coke (kg) Iron ore (kg)

Other metal (kg) Electric power (kWh) City gas (m 3)

Lightweight steelstructure singlefamily house

SRC multi-family house

Wooden single-family house

No. 1

No. 2

No. 1

No. 2

No. 3

No. 4

No. 1

No. 2

365 132 71 18 19 4 354 4 1 232

543 183 99 20 16 10 500 4 1 299

160 30 37 12 6 2 48 2 1 102

100 34 32 13 7 2 53 2 1 88

246 34 35 13 7 3 52 1 99

143 33 32 14 6 2 64 1 1 96

268 69 59 28 15 4 158 2 205

384 62 46 19 9 5 125 2 1 152

~

M. Suzuki et aL / Energy and Buildings 22 (1995) 165-169

168

Multi-family - 1 Multi-family - 2 Wooden - I •

General expenditure

[]

Equipment work



Finishing work

[]

Structural work

Wooden - 2 Wooden - 3 Wooden - 4 Light-weight steel - I Light -weight sttel - 2 0 Fig. 2. E n e r g y c o n s u m p t i o n

2000

400O

6000

8000

10000

12000

(MJ) per m 2 of floor area.

Multi-family- 1 Multi-family - 2

|

Wooden- 1



General expenditure

Wooden - 2 [ ] Equipment work Wooden - 3 •

Finishing work

Wooden - 4 [ ] Structural work Light-weight steel - 1 Light -weight sttel - 2 0 Fig. 3. C a r b o n

100

200

300

400

500

600

700

800

900

1000

d i o x i d e ( k g ) p e r m 2 o f floor a r e a .

5. Carbon dioxide emission The amount of carbon dioxide emission was calculated by using the amount of coal, oil, naphtha, LPG, coke, electric power and city gas listed in Table 3. For cement, the amount of produced carbon was estimated by using data which showed that 0.3 t of carbon dioxide is produced for every ton of cement production due to limestone dissolution [8]. Fig. 3 shows the CO2 emission resulting from housing construction. These values are 850 kg/m2 for SRC multifamily houses, 250 kg/m2 for wooden houses and 400 kg/m2 for lightweight steel-framed single-family houses. CO2 emission resulting from the construction of a typical Danish house was 350 kg/m2 [7] which is 40% greater than that for a Japanese wooden house. The difference between SRC multi-family house No. 1 and No. 2 is mainly caused by the structural work. The difference of CO2 emission per m 2 of floor area among the four wooden houses is very small.

unit construction price and CO2 intensity is the CO2 emission resulting from the construction of houses per unit construction price. Table 4 shows the energy and CO2 intensity in each category of work for each type of house construction. Energy intensity of SRC multi-family houses is approximately 32 M J/1000 yen, 19 MJ/1000 yen for wooden houses, 25 M J/1000 yen for lightweight steel-structure houses. The former report [9] shows that the energy intensity of office buildings was the same as that of SRC multi-family houses (32 M J/1000 yen). The energy intensity of wooden houses is lower than other types of houses because timber and wood panels required lower energy for production than other materials such as concrete and steel. The CO2 intensity is approximately 3.0 kg/1000 yen, 1.6 kg/1000 yen, 2.1 kg/1000 yen, respectively. The proportion among the CO2 intensity is almost the same as the energy intensity.

6. Energy intensity and

7. Conclusions

CO 2

intensity

Energy intensity is the energy consumption including direct and indirect effects for house construction per

Various types of housing construction were analyzed and the amount of energy consumption and CO/emis-

M. Suzuki et al. / Energy and Buildings 22 (1995) 165-169

169

Table 4 Energy intensity (units: MJ/1000 yen) and CO2 intensity (kg/1000 yen) SRC multi-family house

Wooden single-family house

No. 1

No. 2

No. 1

No. 2

No. 3

No. 4

No. 1

No. 2

Energy intensity Temporary work Structural' work Finishing work Equipment work General expenditure Total

21 52 32 20 8 30

16 49 29 27 8 34

18 11 31 27 6 17

8 16 30 53 6 21

16 21 18 36 5 17

29 16 20 40 6 19

27 71 26 43 6 26

18 52 27 33 6 24

CO2 intensity Temporary work Structural work Finishing work Equipment work General expenditure Total

1.5 5.6 2.7 1.4 0.6 2.8

1.2 5.3 2.2 2.3 0.6 3.2

1.4 1.7 2.5 2.2 0.4 1.4

0.6 1.7 2.3 4.3 0.4 1.8

1.5 1.5 1.5 3.5 0.4 1.6

2.2 1.6 1.6 3.4 0.4 1.6

2.0 7.3 2.1 3.1 0.4 2.1

1.4 5.3 2.5 2.8 0.4 2.2

sion was calculated by using the Input/Output Table of Japan. The major results are as follows; (1) Energy consumption for construction is 8-10 GJ per m 2 of floor area for multi-family SRC houses, 3 GJ for wooden single-family houses, 4.5 GJ for lightweight steel-structure single-family houses. Energy consumption due to construction of a wooden house is approximately 1/3 of that of a SRC multi-family house and 60% of that for a lightweight steel-structure singlefamily house. In terms of the construction, the wooden house has less impact on the global environment. (2) Energy consumption for the structural work of wooden single-family houses is only 11% of the energy consumption for multi-family houses. (3) CO2 emission resulting from construction is 850, 250 and 400 kg/m2, respectively. (4) Energy intensity for SRC multi-family houses is approximately 32 MJ/1000 yen, 19 MJ/1000 yen for wooden houses, 25 M J/1000 yen for lightweight steelstructure houses. (5) CO2 intensity is approximately 3.0, 1.6 and 2.1 kg/1000 yen respectively. Construction of house requires a huge amount of energy and accounts for a substantial portion of the nation's energy use. The construction of wooden house has less impact on the global environment compared with other types of house. However, the endurance among the three types of house is different and furthermore household energy usage would vary among the three.

Lightweight steelstructure singlefamily house

To evaluate the life-cycle figures of energy consumption and CO2 emission, it is necessary to establish evaluation methods for energy consumption and CO2 emission resulting from the operation and maintenance of the house and for the endurance of the house.

References [11 Annual Report of Construction Statistics, Research Committee of Construction Price, Tokyo, Japan, 1993 (in Japanese). [2] K. Okada and T. Oka, Application of input/output analysis to buildings: Part 9. Energy consumption and CO2 emission due to the construction divided into house components, Proc. Annual

Meet., The Society of Heating, Air-Conditioning and Sanitary Engineering of Japan, 1994 (in Japanese). [3] Annual Report of Energy, Ministry of International Trade and Industries, Tokyo, Japan, 1985 (in Japanese). [4] 1985 Input/OuOgut Table of Japan, Research Committee of International Trade and Industry, Tokyo, Japan, 1988 (in Japanese). [5] Standard Pricing of Construction Works, Research Committee of Construction Price, Tokyo, Japan, 27th edn., 1986. [6] Cost Analysis Information for Building Works, Management Research Society for Construction Industry of Japan, Tokyo, Japan, 1986 (in Japanese). [7] D. Pedersen, Economic assessment of energy use and environmental impact of construction, CIB W-55 Symposium, 1993. [8] Report of Investigation on Green House Effect of C02 Gas and Measures of Oil lndustry of Japan, Oil Industry Activation Center, Tokyo, Japan, 1988 (in Japanese). [91 T. Oka, M. Suzuki and T. Konnya, The estimation of energy consumption and amount of pollutants due to the construction of buildings, Energy Build., 19 (1993) 303-311.