Input-Output Table for Environmental Analysis of Japan:
Construction and Application
Satoshi NAKANO
Keiichiro ASAKURA
August 2011 (revised)February 2010
KEO Discussion Paper No. 121

Input-Output Table for Environmental Analysis of Japan:
Construction and Application

Satoshi Nakano*
The Japan Institute for Labour Policy and Training
Keio Economic Observatory, Keio University
andKeiichiro Asakura
Faculty of Economics, Ryutsu Keizai University
August 2011 (revised)February 2010
Abstract
This paper presents the construction method of the 2000 Input-Output Table for Environmental Analysis
of Japan and its application study. The first half of the paper describes the construction of energy inputs
and CO2 emissions tables corresponding to the official Input-Output Table by the Ministry of Internal
Affairs and Communications, using economic and energy statistics. The second half quantifies the CO2
emission of new power generation technology; Solar Power Satellites (SPS) as one of the application
study.

Keywords
CO2 emissions, Input-Output Table, Life Cycle Assessment (LCA), Solar Power Satellites (SPS)*

Author for correspondence. The Japan Institute for Labour Policy and Training, 4-8-23 Kamishakujii,
Nerimaku, Tokyo 177-8502, Japan. Tel: +81-3-5903-6223. Fax: +81-3-5903-6118. E-mail:nakano@sanken.keio.ac.jp (or) nakano@jil.go.jp

11. Introduction
Greenhouse gas (GHG) reduction targets of developed countries, including Japan, areprovided in the Kyoto Protocol that came into effect in February 2005. Although Japanis required to reduce GHG emissions by 6% from 1990 levels during the firstcommitment period (2008–2012), domestic emissions have gradually increased instead.
Even so, Prime Minister Hatoyama pledged to reduce emissions by 25% from 1990
levels by 2020 at the UN Climate Change Summit in 2009.
After the third UNFCCC Conference of the Parties (COP3) in 1997,
international discussion regarding measures against global warming has continued, and
COP15 was held in 2009. COP15 introduced the Copenhagen Accord and outlined
measures to be implemented after 2013. However, forging an international consensus isa challenging task.
Our research group of environmental issues at Keio Economic Observatory,
Keio University, has tried to construct the Input-Output Table for Environmental
Analysis (IOTEA) 1985 and has addressed global warming issues based on the database.
We used officially published information as much as possible for constructing the
IOTEA 1995 (Asakura et al. 2001) and enhanced the repeatability of constructing thedatabase. The IOTEA 2000 (Nakano et al. 2008) was constructed using the 2000
Input-Output Table of Japan, and a framework for analyzing CO2 emission structures by
economic activities was prepared.1
The IOTEA is not only a basic reference for life cycle assessment (LCA) of
technologies but also a database for scenario analysis of recycling processes andmulti-sectoral economic models. If other countries construct the IOTEAs using common
concepts and classifications and these tables are linked, the environmental impact oftechnology transfer and carbon leakage can be assessed.
This paper presents the construction method for the IOTEA 2000 of Japan andits application to case studies. The first half of the paper describes the construction of
the table with energy inputs and CO2 emissions corresponding to the official 2000
Input-Output Table constructed by the Ministry of Internal Affairs and Communications
using economic and energy statistics. The second half quantifies the CO2 emission of anew power generation technology as an application case study.

1

Nakano (2009) has already constructed the IOTEA 2005. However, because studies have still not been
conducted using this database, we introduce the estimation method for the IOTEA 2000 and its
application study in this paper.

22. Composition of IOTEA of JapanThe IOTEA of Japan consists of six tables (Figure 1): (1) monetary inputs of raw
materials, including the energy goods listed in Table 1; (2) physical inputs of energy
goods (original unit); (3) physical inputs of energy goods (calorie basis); (4) physicalinputs of energy goods (CO2 basis); (5) physical inputs of energy goods for non-energyuse (CO2 basis); and (6) CO2 emissions.
The monetary input table shows the monetary inputs of raw materials by
activities valued at producer prices. We used the transaction table (basic sector
classification: 405 column sectors, 517 row sectors) of the 2000 Input-Output Table as
the monetary input table of the IOTEA. For analysis using the square table by sector
aggregation, the following aggregation method is employed. First, row sectors areaggregated using six digits from the top of the seven-digit row code to reduce thenumber of row sectors to 401. Next, the square monetary input table (399 × 399) is
derived by aggregating both column and row sectors based on Table 2.
The physical input table (original unit) shows the physical inputs of energy
goods listed in Table 1 for each activity, by weight or volume. These energy goods
include limestone, iron, and steel. Limestone, pig iron, crude steel (converters andelectric furnaces), iron scrap, and blast furnace dust are required to calculate the carbon
balance. These goods also include substitutable goods such as fly ash, blast furnace slag,
converter slag, and electric furnace slag for other inputs that contain carbon.
By using the heating value per weight or volume as listed in Table 1, we cantransform the physical input table (original unit) into the physical input table (calorie
basis). Because the physical input table (calorie basis) shows the total heating value ofenergy inputs, we can identify energy-intensive sectors.
We can obtain the physical input table (CO2 basis) by using the carbon content
per weight or calorie as well as the physical input table (calorie basis). The physicalinput table (CO2 basis) indicates that carbon in the inputs is fully emitted as CO2.
However, there are energy inputs for non-energy use. Hence, carbon in inputs for
non-energy use should be deducted from the physical input table (CO2 basis). This
deduction is described in the physical input table of energy goods for non-energy use(CO2 basis). The CO2 emissions table is constructed by deducting the energy inputs for
non-energy use from the energy inputs (CO2 basis).

3Activity

Commodityi = 1, …, 517

Energygoods

k = 1, …, 51

Physical input table (original unit)

Energygoods

k = 1, …, 51

Physical input table (calorie basis)

Energygoods

k = 1, …, 51

Physical input table (CO2 basis)

Energygoods

k = 1, …, 51

Physical input for non-energy use(CO2 basis)

Energygoods

k = 1, …, 51

j = 1, …, 405

CO2 emissions table

Monetary input table(Endogeneous sectors)(Final demand)

Figure 1: Composition of Input-Output Table for Environmental Analysis (IOTEA)

4

Table 1: Energy goods in IOTEA 2000
Energy goods

Original unit

Heating value
per original unit
MJ/Unit

CO2 emissions
per heating value
kg-CO2/GJ

1 Limestone
2 Fly ash
3 Blast furnace slag
4 Converter slag
5 Electric furnace slag
6 Coking coal
7 Steam coal
8 Crude petroleum
9 Natural gas
10 LNG
11 Gasoline
12 Jet fuel oils
13 Kerosene
14 Light oils
15 Heavy oil A
16 Heavy oil B and C
17 Naphtha
18 LPG (liquefied petroleum gas)
19 Oil produced by conversion
20 Hydrocarbon oil
21 Hydrocarbon gas
22 Petroleum coke
23 Coke
24 Coke oven gas

t
t
t
t
t
t
t
kl

1000m3

31814
25426
38721
41023
54418
35162
36418
37255
38511
38930
41023
33488
50232
33488
41023
39348
35581
30139
20093

25 Blast furnace gas

1000m3

3349

99.32

26 Converter furnace gas

1000m38372

141.4427 Electric furnace gas
28 Tar29 Crude benzene
30 Pig iron
31 Crude steel (converters)
32 Crude steel (electric furnaces)
33 Pig iron scrap
34 Steel scrap
35 Electricity
36 Private power generation
37 Gas supply
38 Steam and hot water supply
39 Black liquor
40 General waste
41 Scrap wood
42 Animal and plant residues
43 Paper scrap
44 Wood waste
45 Waste textile
46 Waste oil
47 Waste plastic
48 Sludge
49 Waste tire
50 Blast furnace dust
51 Used paper

1000m3
t
t
t
t
t
t
t
million kWhmillion kWh

8372
32065

183.2589.15

1000m3
t
kl
kl
kl
kl
kl
kl
kl
t
kl
t
1000m3tt

Carbon content(ratio by weight)
0.120

81.61
94.75
67.64
50.81
49.57
66.03
67.62
66.82
68.01
69.60
72.68
67.95
59.73
70.45
77.09
59.41
93.18
107.66
42.36

0.923
0.040
0.003
0.003
0.040
0.003
3599960
3599960
41860
1000
12558
6614
16744

1000m3GJ
bone-dry ttbone-dry t
t
t
t
t
t
t
t
t
t
t

49.68
94.17
84.40
76.99

18795
17581

90.45
96.69

27000
32341
14651
32341

108.10
79.02
75.08
54.31
0.300

Source) IOTEA 2000

5

Table 2: Sector aggregation for IOTEA 2000
IOTEA
Column sector
011300 Vegetables
031100Marine fisheries(domestic)

031200Inland water fisheries and culture

261101271109511100Pig iron
Other non-ferrous metals
Electricity

Row sector
011300 Vegetables
031100 Marine fisheries(domestic)
031200 Inland water fisheries and culture
261101 Pig iron
271109Other non-ferrous metals

511100Electricity

official IO
011301011302031101031102031103031201031202261101271109511101511102511103

Vegetables(outdoor)
Vegetables(under facilities)
Coastal fisheries
Off-shore fisheries
Distant water fisheriesInland water fisheriesInland water culture
Pig iron
Other non-ferrous metals
Electricity(nuclear power)
Electricity(thermal power)
Electricity(water power, etc.)

011300031100031200261101261201271109271201511100Vegetables
Marine fisheries(domestic)
Inland water fisheries and culture
Pig iron
Scrap iron
Other non-ferrous metals
Non-ferrous metal scrap
Electricity

3. Estimation
First, we construct the table that shows the physical inputs of energy goods (originalunit), using economic and energy statistics. Next, the energy input table (original units)
is converted into tables that describe the physical inputs of energy goods (calorie basis
and CO2 basis) by per unit heat quantity and carbon content. Third, we estimate theenergy inputs for non-energy use (CO2 basis) from the information on energy
consumption by usage. Finally, the CO2 emissions table is built by deducting the energy
inputs for non-energy use from the energy inputs (CO2 basis).
3.1. Physical input table (original unit)
3.1.1 Physical input table of 2000 Input-Output Table
The physical inputs of coking coal, steam coal, crude petroleum, gasoline, jet fuel oils,
kerosene, light oils, heavy oil A, heavy oil B and C, naphtha, Liquefied petroleum gas(LPG), coke, electricity, gas supply, and steam and hot water supply are based on thephysical input table of the 2000 Input-Output Table. Although the physical inputs ofcoal are available from the physical input table of the 2000 Input-Output Table, we
6cannot divide it into coking and steam coal. Therefore, we divided coal inputs in the2000 Input-Output Table using the coking and steam coal shares in the physical input
table of the 1995 Input-Output Table.
3.1.2 Natural gas and liquid natural gas (LNG)
Natural gas and LNG consumption is estimated by the transaction table of the 2000
Input-Output Table and Japan Exports & Imports 2000. The natural gas sector in thetransaction table includes natural gas and LNG. The transaction table shows not only themonetary input of domestic natural gas but also the monetary input of imported naturalgas. All LNG is imported, while all natural gas is domestically produced. Therefore, thedomestic natural gas in the transaction table denotes so-called natural gas, and theimported gas denotes LNG. Natural gas and LNG consumption is estimated by dividing
the monetary inputs of domestic and imported gas in the transaction table by the unit
prices of natural gas and LNG, respectively. Table 3 shows the unit prices of theseenergy goods.
Table 3: Unit price of LNG and natural gas in 2000
Unit
yen/t

LNG
Natural gas yen/1000m3

Price
28,19931,494

Source) 2000 Input-Output Table and Japan Exports & Imports 2000

3.1.3 Byproduct gas and other energy inputs
3.1.3.1 Mining and manufacturing sector
The consumption of oil produced by conversion, hydrocarbon oil, hydrocarbon gas,petroleum coke, coke oven gas, blast furnace gas, converter furnace gas, electric furnace
gas, and waste tires in the mining and manufacturing sectors (excluding ten iron andsteel sectors and the petroleum refinery products sector) is described in the Structural
Survey of Energy Consumption in Commerce and Manufacturing 2000.
The industry classification in the Structural Survey is based on theclassification in the Census of Manufacturers 2000. This classification is not consistent
with the sector classification of the 2000 Input-Output Table. Hence, we converted theenergy consumption of the former into the latter using a bridge table between the
Census of Manufacturers and the Input-Output Table that was included in the 2000
Input-Output Table.
The energy consumption in the Structural Survey includes the consumption for7boilers to obtain heat and electricity. The private power generation of each industry isreported in the private power generation sector of the Input-Output Table. Therefore, we
divided the energy consumption for boilers into the consumptions for generating
electricity and obtaining heat by using the amount of private power generation and thethermal efficiency for power generation (38.1%). The former was allocated to theprivate power generation sector of the Input-Output Table.
3.1.3.2 Ten iron and steel sectors
The consumption of hydrocarbon oil, petroleum coke, coke oven gas, blast furnace gas,
converter furnace gas, electric furnace gas, tar, and iron scraps in ten iron and steel
sectors, including pig iron, ferroalloys, crude steel (converters and electric furnaces),
hot-rolled steel, steel pipes and tubes, cold-finished steel, coated steel, cast and forgedsteel, and cast and forged materials (iron) was obtained from the Yearbook of Iron andSteel Statistics 2000. The byproduct gas yield is also available from this publication.
The energy consumption for power generation and boilers in the iron and steel sectors isdivided by the steam consumption for power generation and production process. Table 4shows the corresponding relationship between the Yearbook and IOTEA. The energy
consumption of ten iron and steel sectors (Table 5) was estimated based in Table 4.
Table 4: Bridge table between Yearbook of Iron and Steel Statistics and IOTEA
Yearbook of Iron and Steel Statistics
For sintering
For pellets
For iron-making
For ferro-alloys
For steel-making(LD converters)
For steel-making(electric furnaces)
For steel forgings
For steel castings
For rolled steel, and steel pipes and tubes

IOTEA
Pig iron

Ferro alloys
Crude steel (converters)
Crude steel (electric furnaces)
Cast and forged steel
Hot rolled steel
Steel pipes and tubes
Cold-finished steel
Coated steel
Private power generation
Ten iron and steel sectors
Coal products

Other iron and steel sector
For power generation, boiler and co-generation
Coke production sector8

Table 5: Energy consumption of ten iron and steel sectors in 2000
Coke ovengas

Balst furnace Convertergasfurnace gas

Electric
furnace gas

1000m31000m31000m31000m3
Yearbook of Iron and Steel Statistics and Structural Survey of Energy Consumption in Commerce and Manufacturing
For sintering
157,390
57,197
29,4090
For pellets
52,235000For iron-making
1,533,700
31,657,698
1,097,780
0
For ferro-alloys
3,741
1,455
5,005
6,565
For steel-making(LD converters)
334,090
8,981
19,8570
For steel-making(electric furnaces)
27,534680
2,630
0For steel forgings
38,447
2,002
7,799
0
For steel castings
2,654
0
0
0
For rolled steel, and steel pipes and tubes
4,166,929
1,342,584
1,517,7280For power generation, boiler and co-generation
1,555,768
34,648,421
2,245,809
0Other iron and steel sector
380,777
1,559,431
34,6860
Coke production sector
1,474,748
16,407,326
206,7220Cast and forged materials (iron)
53
0
0
0
Total
9,728,066
85,685,775
5,167,425
6,565
Input-Output Table for Environmental Analysis
Pig iron
1,869,002
41,562,807
1,416,568
0Ferro alloys
4,011
1,907
6,290
6,565
Crude steel (converters)
358,175
11,77024,9550
Crude steel (electric furnaces)
29,519891
3,305
0
Hot rolled steel
2,597,832
1,023,167
1,109,1700Steel pipes and tubes
412,166
162,333
175,9780Cold-finished steel
1,457,328
573,975
622,220
0
Coated steel
408,227
2,043,656
43,5910Cast and forged steel
44,064
2,624
9,801
0
Cast and forged materials (iron)57000Private power generation
1,072,937
23,895,320
1,548,8250
Coal products
1,474,748
16,407,326
206,7220
Total
9,728,066
85,685,775
5,167,425
6,565

Hydrocarbon Petroleum
oil
coke
kl
t
0
0
0
0
0
0
0
0
0
0
0
142,0100
142,01000601,745
6,526
0
6,668
0
0
0
0
54
566,47401,181,467

0
0
0
0
0
0
0
0
0
0
0
142,010142,010

601,745
6,526
0
6,668
0
0
0
54
0
0
0
566,474
1,181,467

Source) Input-Output Table 2000, Yearbook of Iron and Steel Statistics 2000, Structural Survey of Energy
Consumption in Commerce and Manufacturing 2000, and IOTEA 2000

3.1.3.3 Three pulp and paper and petroleum refinery products sectors
The black liquor and scrap wood consumption of the pulp, paper, and paperboard
sectors is included in the Yearbook of the Current Survey of Energy Consumption in
Manufacturing 2000. The consumption of hydrocarbon oil, hydrocarbon gas, andpetroleum coke in the petroleum refinery products sector is also included in thispublication. The consumption for boilers of these sectors is divided into theconsumption for private power generation and the production process by the steam
consumption. Tables 6 and 7 show the black liquor and scrap wood consumption of thepulp and paper sectors, respectively. Table 8 shows the energy consumption of thepetroleum refinery products sector.

9

Table 6: Black liquor consumption of three pulp and paper sectors in 2000
(Unit: bone-dry t)Consumption incl.
Consumption for
Consumption excl.
Share of private
private power
private power
private power
power generation
generation use
generation
generation use
Pulp
5,933,778
0.463
2,750,183
3,183,595
Paper
7,898,600
0.463
3,660,837
4,237,763
Paperboard
762,1880.463
353,258
408,930
Source) Yearbook of Current Survey of Energy Consumption in Manufacturing 2000 and IOTEA 2000

Table 7: Scrap wood consumption of three pulp and paper sectors in 2000
(Unit: bone-dry t)Consumption incl.
Consumption for
Consumption excl.
Share of private
private power
private power
private power
power generation
generation use
generation
generation use
Pulp
71,3470.393
28,05443,293Paper
224,246
0.393
88,174136,072
Paperboard
53,071
0.393
20,86832,203
Source) Yearbook of Current Survey of Energy Consumption in Manufacturing 2000 and IOTEA 2000

Table 8: Hydrocarbon oil, petroleum oil, and hydrocarbon gas consumption of
petroleum refinery products sector in 2000
Unit
Hydrocarbon oil
Petroleum coke
Hydrocarbon gas

klt
1000m3

Consumption incl.
Consumption for
Consumption excl.
Share of private
private power
private power
private power
power generation
generation use
generation
generation use
203,346
0.289
58,845
144,501
142,624
0.289
41,273
101,351
8,848,048
0.043
382,927
8,465,121

Source) Yearbook of Current Survey of Energy Consumption in Manufacturing 2000 and IOTEA 2000

3.1.3.4 Electricity (thermal power) sector
The consumption of coke oven, blast furnace, and converter furnace gases in thethermal power electricity sector is described in the Outline of Electricity Demand andSupply FY 1999 and 2000. Table 9 shows the energy consumption of the electricity(thermal power) sector.

10Table 9: Coke oven gas, blast furnace gas, and converter furnace gas of electricity(thermal) sector in 2000
Unit
Coke oven gas

1000m

Consumption
2,350,952

Blast furnace gas

1000m340,385,092

3

1,477,861

Converter furnace gas

3

1000m

Source) Outline of Electricity Demand and Supply 1999 and 2000

3.1.3.5 Gas supply sector
The consumption of coke oven, hydrocarbon, and methane gases in the gas supply
sector is based on the Yearbook of the Gas Supply 2000. We related the coal and off
gases included in other gases to coke oven and hydrocarbon gases, respectively. Table
10 represents the energy consumption of the gas supply sector.
Table 10: Gas consumption of gas supply sector in 2000
Unit
Coke oven gas

1000m

Consumption
218,209

Hydrocarbon gas

1000m381,626

Methane gas

1000m3

720

Digestion gas

3

391

3

1000m

Source) Yearbook of Gas Supply 2000

3.1.4 General and industrial waste
The amount of incinerated general waste and industrial waste—including slag, metal
scrap, animal excreta, construction and demolition waste, animal and plant residues,
dust, paper scrap, glass and pottery waste, waste oil, combustion residue, animal carcass,wood waste, waste plastic, waste acid, waste textile, waste rubber, sludge, and waste
alkali—is estimated using the State of Discharge and Treatment of Industrial Waste andthe State of Discharge and Treatment of Municipal Solid Waste for FY 2000.
General waste management is allocated to the waste management service(public) sector in the Input-Output Table, and the incineration disposal amount ofgeneral waste is available from the report. Industrial waste management is allocated to
the waste management services (private) sector. Because industrial waste is incinerated
to reduce the volume in the intermediate process, we treat the reduced amount of
incinerated waste such as paper scraps and wood waste as the incinerated amount. The
11

incinerated amount of waste oil, waste plastic, and sludge is estimated using the ratio of
the incinerated amount to the total amount in the IOTEA 1990 (Ikeda et al. 1996). Table
11 shows the incinerated amount of general and industrial wastes in 2000.
Table 11: Incinerated waste in 2000
Unit
General waste
Industrial waste

paper scrap
wood waste
waste oilwaste plastic
sludge

t
t
t
t
t
t

Incinerated
IOTEA
amount40,304,000 Waste management services (public)
898,413 Waste management services (private)
2,901,729 Waste management services (private)921,106 Waste management services (private)
1,005,945 Waste management services (private)
5,340,089 Waste management services (private)

Source) State of Discharge and Treatment of Industrial Waste, State of Discharge and Treatment ofMunicipal Solid Waste and IOTEA 1990

3.1.5 Slag of blast furnace, converter and electric furnace, dust of blast furnace and flyash
The generation and utilization of blast furnace, converter, and electric furnace slag are
obtained from the Statistical Yearbook of Iron and Steel Slag. The information on fly ash
is based on a discussion with the Japan Fly Ash Association. The generation of blast
furnace dust is estimated using the dust generation per unit production of pig iron in the
IOTEA 1990.
3.2 Physical input table (calorie basis)
The physical input table (calorie basis) is converted from the physical input table(original unit) using the heating value per original unit (Table 1). This table shows
which sector is energy intensive.
3.3 Physical input table (CO2 basis), physical input table for non-energy use (CO2 basis),and CO2 emission table
The physical input table (CO2 basis) is calculated by multiplying the physical input
table (calorie basis) and CO2 emissions per heating value listed in Table 1. The physicalinput table for non-energy use (CO2 basis) is estimated using the combustion ratio or
carbon balance table methods. The CO2 emissions table is then built by deducting thephysical input table for non-energy use (CO2 basis) from the physical input table (CO2basis).
12

The combustion ratio method for estimating the physical input table fornon-energy use (CO2 basis) calculates the combusted proportion of the total inputs ofenergy goods and removes the combustion amount from the total inputs. In contrast, thecarbon balance table method estimates the carbon content of outputs and uses it as thephysical input for non-energy use. We applied the carbon balance table method to fivesectors, including the coal products, pig iron, crude steel (converters), crude steel(electric furnaces) and gas supply sectors. The combustion ratio method was applied to
the rest of sectors.
3.3.1 Combustion ratio method (Structural Survey of Energy Consumption in Commerceand Manufacturing 2000)
We applied the combustion ratio method to 400 sectors in the IOTEA. The combustion
ratio in nine petrochemical products and chemical fertilizer sectors is based on the
Yearbook of the Current Survey of Energy Consumption in Manufacturing 2000, while
the ratio in the petroleum refinery products sector is estimated from the Yearbook of
Production Supply and Demand of Petroleum, Coal and Coke 2000 and the Structural
Survey of Energy Consumption in Commerce and Manufacturing 2000. We assumed
that all combustion ratios of the primary and tertiary industry sectors in the other 389
sectors are equal to one. The combustion ratio of the secondary industry sector in 389
sectors is based on the Structural Survey of Energy Consumption in Commerce andManufacturing 2000.
However, we have given the combustion rate of certain energy goods. We
converted the classification of the Structural Survey of Energy Consumption in
Commerce and Manufacturing into that of the Input-Output Table using only thecorresponding relationship between the shipment of the former and production of thelatter. Therefore, the converted energy consumption may be not consistent with theclassifications of the Input-Output Table. We used the following assumptions to tackle
the problem. All coke oven gas, blast furnace gas, converter furnace gas, electric
converter gas, gasoline, light oils, jet fuel oil, black liquor, scrap wood, general waste,
paper scrap, wood waste, waste oil, waste plastic, sludge and waste tire were burned for
all cases (i.e., the combustion ratio of these energy goods was equal to one). All coking
coal was combusted in the chemical fertilizer and ferroalloy sectors, which do not
produce coke, while no coking coal was combusted in the other sectors.
The

Structural

SurveyofEnergyConsumptioninCommerce

andManufacturing reports energy consumption as raw materials. The combustion amount isestimated by deducting the consumption as raw materials from the total consumption,
13

and the combustion ratio is obtained by dividing the combustion amount by the total
consumption.
3.3.2 Combustion ratio method (Yearbook of the Current Survey of Energy Consumptionin Manufacturing 2000)
The combustion ratios in nine petrochemical product sectors and the chemical fertilizer
sector are based on the Yearbook of the Current Survey of Energy Consumption in
Manufacturing 2000. The nine petrochemical product sectors include petrochemical
basic products, petrochemical aromatic products, aliphatic intermediates, cyclic
intermediates, synthetic rubber, thermo-setting resins, thermoplastics resins, highfunction resins, and other resins. We assumed the same combustion rate for the nine
petrochemical products sectors. Tables 12 and 13 show the combustion ratios of energy
goods in the nine petrochemical product sectors and the chemical fertilizer sector,
respectively.
Table 12: Combustion share of nine petrochemical products sectors in 2000
Unit
Kerosene
NaphthaLPG
Oil produced by conversion

kl
kl
t
kl

Consumption incl.
Consumption for
Combustion
non-energy use
non-energy use
share
1,094,258
992,762
0.093
35,639,148
35,639,148
0.000
4,395,741
3,985,356
0.093
16,823,249
16,823,249
0.000

Source) Yearbook of Current Survey of Energy Consumption in Manufacturing 2000

Table 13: Combustion share of chemical fertilizer sector in 2000
Unit
Natural gas
Naphtha
LPG
Hydrocarbon gas

1000m3kl
t1000m3

Consumption incl.
Consumption for
Combustion
non-energy use
non-energy use
share
167,873
87,3100.480
483,224453,2640.062
30,3096,949
0.771
344,954
228,348
0.338

Source) Yearbook of Current Survey of Energy Consumption in Manufacturing 2000

3.3.3 Combustion ratio method (Yearbook of Production Supply and Demand of
Petroleum, Coal and Coke 2000)
The combustion ratio in the petroleum refinery product sector is calculated using the
Yearbook of Production Supply and Demand of Petroleum, Coal and Coke 2000 and theStructural Survey of Energy Consumption in Commerce and Manufacturing 2000. If the14

ratios obtained from the two sources were different, we selected the lower one. Table 14
represents the combustion ratio of energy goods in the petroleum refinery products
sector.
Table 14: Combustion share of petroleum refinery products sector
Unit
Steam coal
Kerosene
Light oils
NaphthaPetroleum coke
LPG

t
kl
kl
kl
t
t

Consumption incl.
Consumtion for
Combustion
non-energy use
combustion
share
198,399
195,869
0.98725
92,07341,4550.450242,752
1480.05378
60,5570.3
0.00001
1,965
1,872
0.95303
180,042
37,1430.20630

Source) Yearbook of Production Supply and Demand of Petroleum, Coal and Coke 2000, and Structural
Survey of Energy Consumption in Commerce and Manufacturing 2000

3.3.4 Combustion ratio of limestone
Limestone initiates a chemical reaction when it is heated or added to acid and the CO2 isdischarged. Most sectors consume limestone through the chemical reaction. However,
the materials for ceramics sectors only crush the limestone, and the combustion ratio oflimestone is equal to zero in this sector. The combustion ratio of limestone is estimatedusing information for 1995 from the Central Research Institute of Electric Power
Industry (Hondo et al. 2002).
3.3.5 Physical input of gas supply
The Structural Survey of Energy Consumption in Commerce and Manufacturing 2000
reports LNG consumption of the chemical industries, while the Input-Output Table 2000
reports LNG consumption of only three sectors: gas supply, electricity (thermal), andprivate power generation. The LNG data of the Structural Survey includes the LNG
supplied by gas suppliers. On the other hand, the Input-Output Table reports the LNG
supplied by gas suppliers in the gas supply sector.
The cyclic intermediates, synthetic dyes, and organic pigment manufacturing
data of the Structural Survey consider LNG as a raw material. Therefore, if the sectors
shown in the Input-Output Table in relation to these manufacturing sectors burn all of
their gas supply, the CO2 emissions might be overestimated. Hence, when calculating
the combustion ratio of the gas supply, the combusted gas supply of the sectors that
consume LNG as raw material is estimated by deducting the gas supply as raw material
15

from total gas supply inputs.
3.3.6 Carbon balance table method
We applied the carbon balance table method to the coal product, pig iron, crude steel(converters), crude steel (electric furnaces), and gas supply sectors. The carbon balancetable shows the carbon content of inputs and outputs like a balance sheet. CO2
emissions are calculated by deducting the total carbon content of inputs from the total
carbon content of outputs.
We developed a material balance table that shows the physical inputs andoutputs (original unit) and then converted the physical quantity (original unit) of thematerial balance table into carbon using the information listed in Table 1. Tables 15–19
show the material balance table of the pig iron, crude steel (converters), crude steel(electric furnaces), and gas supply sectors. Tables 20–24 show the carbon balance tablebased on Tables 15–19.
Table 15: Material balance table of coal products sector in 2000
Unit
t
t
kl
kl
kl
kl
kl
t
1000m3tt

Input
Output
67,858,120
60,000
56
8,069
260
1,670
383
142,092356
566,672
38,562,016

Coke oven gas

1000m3

13,994,001

Blast furnace gas

1000m318,904,221

Converter furnace gas
Tar
Crude benzene
Gas supply

1000m3tt363,9161000m3605

Coking coal
Steam coal
Gasoline
Kerosene
Light oils
Heavy oil A
Heavy oil B and C
Hydrocarbon oil
Hydrocarbon gas
Petroleum coke
Coke

Source) IOTEA 2000

16

1,561,026
519,867

Table 16: Material balance table of pig iron sector in 2000
Unit
t
t
t

Limestone
Coking coal
Steam coal
Natural gas
Kerosene
Heavy oil A
Heavy oil B and C
LPG
Petroleum coke
Coke
Coke oven gas

1000m3
kl
kl
kl
t
t
t
1000m3

Input
Output17,753,143
397,518
5,043,956
1,334
75
1,507
33,9588,259
601,745
35,960,569
2,379,125Blast furnace gas

1000m3

41,562,807

Converter furnace gas

1000m3ttt

1,416,568

Tar
Pig iron
Pig iron scrap
Gas supply
Blast furnace dust

132,380,518

52,695
81,105,642
2,488
1,532

3

1000m
t

1,217,351

Source) IOTEA 2000

Table 17: Material balance table of crude steel (converters) sector in 2000
Unit
t
t

1000m3

Input
Output17,794,346
730
222
9,711
18,4882,473
851
96,054455,934

Blast furnace gas

1000m3

11,770Converter furnace gas

1000m3t24,955

Limestone
Steam coal
Natural gas
Kerosene
Heavy oil A
Heavy oil B and C
LPG
Coke
Coke oven gas

1000m3
kl
kl
kl
t
t

Pig iron
Crude steel (converters)
Pig iron scrap
Steel scrap
Gas supplyttt

8,437,446

77,145,345
75,793,461

1000m3557,251
6,274,734
15,057

Source) IOTEA 2000

17

Table 18: Material balance table of crude steel (electric furnaces) sector in 2000
Unit
t
t

Limestone
Steam coal
Natural gas
Kerosene
Heavy oil A
Heavy oil B and C
LPG
Petroleum coke
Coke
Coke oven gas
Blast furnace gas
Converter furnace gas

1000m3
kl
kl
kl
t
t
t

Input
Output
1,003,835
558
1,048
9,002
10,466
2,002
1,048
6,668
74,0841000m337,576

3

1000m

891

3

3,305

1000m

3

Electric furnace gas
Pig iron
Crude steel (electric furnaces)
Pig iron scrap
Steel scrap
Gas supply

98,148

1000m
t
t
t
t

1,780,351
30,665,213
742,01430,028,684
21,2451000m3

Source) IOTEA 2000

Table 19: Material balance table of gas supply sector in 2000
Coking coal
Steam coal
Natural gas
LNG
Kerosene
Heavy oil B and C
Naphtha
LPG
Hydrocarbon gas
Coke oven gas
Gas supply
Methane gas

Unit
t
t

Input

Output1000m340,298442
1,397,788
15,562,894
412
427
1,027,075
1,808,427
408,377

1000m3615,2873

1000m

305,9723

720

1000m3
t
kl
kl
kl
t

1000m

Source) IOTEA 2000

18

25,734,147

Table 20: Carbon balance table of coal products sector in 2000 (Unit: t-C)
Coking coal
Steam coal
Gasoline
Kerosene
Light oils
Heavy oil A
Heavy oil B and C
Hydrocarbon oil
Hydrocarbon gas

Input
Output48,046,942
39,421
35
5,478
186
1,234
311
122,554
227

Petroleum coke

512,407

Coke

34,125,070

Coke oven gas
Blast furnace gas
Converter furnace gas
Tar
Crude benzene
Gas supply
Total
CO2

3,248,008
1,714,726
117,525
1,216,929
479,837
343
50,561,390

39,069,844
11,491,546

Source) IOTEA 2000

Table 21: Carbon balance table of pig iron sector in 2000 (Unit: t-C)
Limestone
Coking coal
Steam coal
Natural gas
Kerosene
Heavy oil A
Heavy oil B and C
LPG
Petroleum coke
Coke
Coke oven gas
Blast furnace gas
Converter furnace gas
Tar
Pig iron
Pig iron scrap
Gas supply
Blast furnace dust
Total
CO2

Input
Output2,130,377
281,462
3,313,980
758
51
1,114
27,613
6,758
544,122
31,822,946
552,195
3,769,996 12,007,707
457,472
41,0793,244,226100
869
365,205
42,950,892 15,617,138
27,333,754

Source) IOTEA 2000

19

Table 22: Carbon balance table of crude steel (converters) sector in 2000 (Unit: t-C)
Input
Output2,135,322
480
126
6,593
13,6622,011
696
85,002
105,8221,068
8,059 2,724,823
3,085,814
227,380
22,29018,8248,540
5,494,310 2,952,203
2,542,107

Limestone
Steam coal
Natural gas
Kerosene
Heavy oil A
Heavy oil B and C
LPG
Coke
Coke oven gas
Blast furnace gas
Converter furnace gas
Pig iron
Crude steel (converters)
Pig iron scrap
Steel scrap
Gas supply
Total
CO2

Source) IOTEA 2000

Table 23: Carbon balance table of crude steel (electric furnaces) sector in 2000 (Unit:
t-C)
Limestone
Steam coal
Natural gas
Kerosene
Heavy oil A
Heavy oil B and C
LPG
Petroleum coke
Coke
Coke oven gas
Blast furnace gas
Converter furnace gas
Electric furnace gas
Pig iron
Crude steel (electric converters)
Pig iron scrap
Steel scrap
Gas supply
Total
CO2

Input
Output120,460
367
596
6,112
7,734
1,628
858
6,029
65,560
8,721
81
1,067
41,067
71,214
91,996
29,681
90,086
12,050422,243 133,063
289,181

Source) IOTEA 2000

20

Table 24: Carbon balance table of gas supply sector in 2000 (Unit: t-C)
Input
Coking coal
Steam coal
Natural gas
LNG
Kerosene
Heavy oil B and C
Naphtha
LPG
Hydrocarbon gas
Coke oven gas
Gas supply
Methane gas
Total
CO2

28,533
290
794,656
11,450,399
280
347
637,423
1,479,763
260,373
142,808
173,541387
14,968,802

Output14,595,893
14,595,893
372,909

Source) IOTEA 2000

4. Results
Table 25 shows the results obtained by aggregating the sector classifications. Japan’s
CO2 emission in 2000 was approximately 1.354 billion tons CO2, which represents anincrease of 3.1% compared with 1995 emission levels.2 The National Institute forEnvironmental Studies estimate (Nansai and Moriguchi 2006) was 1.326 billion tons
CO2.
The top three sectors in terms of CO2 emissions are as follows: the electricity,gas, and heat supply sector (0.393 billion tons CO2); the transport sector (0.193 billion
tons CO2); and consumption expenditure (private, 0.174 billion tons CO2), in that order.
The emissions in the consumption expenditure (private, 24 million tons CO2) and theelectricity, gas, and heat supply sector (21 million tons CO2) showed the largest
increase.
The emissions for the communication and broadcasting, public administration,and electrical machinery have rapidly been increasing (57.6%, 47.8%, and 39.4%,
respectively), while the emissions of textile products, consumption expenditure outside
households, and petroleum and coal products have been considerably reduced (－30.7%,－25.5%, and －19.6%, respectively).
Table 26 shows CO2 emissions by energy goods in 2000. The negative value ofthe table denotes the carbon content of outputs.

2

According to IOTEA 2005, Japan’s CO2 emission in 2005 was approximately 1.400 billion tons CO2.

21

Table 25: CO2 emissions by sector in 1995 and 2000
1995
2000
GrowthEmisssions
Share Emissions
Share 1995-2000
t-CO2
%
t-CO2
%
%
20,446,520
1.6
16,848,417
1.2
-17.6
770,8610.1
763,4090.1-1.0
14,977,620
1.1
14,662,041
1.1-2.1
5,251,253
0.4
3,639,174
0.3-30.7
30,497,052
2.3
30,524,256
2.3
0.1
46,361,400
3.5
48,271,757
3.6
4.1
90,380,493
6.9
72,629,713
5.4
-19.6
99,611,766
7.6
88,969,799
6.6
-10.7
96,826,806
7.4
131,702,770
9.7
36.0
5,271,842
0.4
5,163,190
0.4-2.1
3,799,588
0.3
4,281,744
0.3
12.7
3,007,966
0.2
3,734,340
0.3
24.1
3,949,852
0.3
5,505,275
0.4
39.4
4,896,870
0.4
5,706,417
0.4
16.5
398,7260.0
532,365
0.0
33.5
6,072,431
0.5
7,682,751
0.6
26.5
15,508,430
1.2
13,844,529
1.0
-10.7
372,257,006
28.3
393,005,951
29.0
5.6
49,270,767
3.8
47,096,719
3.5-4.4
13,882,135
1.1
12,680,898
0.9-8.7
1,109,870
0.1
1,220,418
0.1
10.0
3,175,160
0.2
3,214,177
0.2
1.2
208,086,963
15.8
193,469,233
14.3
-7.0
1,017,307
0.1
1,602,811
0.1
57.6
10,697,508
0.8
15,806,927
1.2
47.8
9,951,649
0.8
11,387,279
0.8
14.4
12,330,404
0.9
13,517,487
1.0
9.6
1,199,628
0.1
1,196,242
0.1-0.3
5,534,919
0.4
6,290,060
0.5
13.6
22,118,376
1.7
21,720,041
1.6
-1.8
0
0.0
0
0.0
0.0
3,009,736
0.2
1,679,750
0.1-44.2
1,872,853
0.1
1,395,770
0.1-25.5
149,812,625
11.4
174,168,007
12.9
16.3
1,313,356,384 100.0
1,353,913,717 100.0
3.1

Agriculture, forestry and fishery
MiningFoods
Textile products
Pulp, paper and wooden products
Chemical products
Petroleum and coal products
Ceramic, stone and clay products
Iron and steel
Non-ferrous metals
Metal products
General machinery
Electrical machineryTransportation equipment
Precision instruments
Miscellaneous manufacturing products
Construction
Electricity, gas and heat supply
Water supply and waste management services
Commerce
Financial and insurance
Real estateTransport
Communication and broadcasting
Public administration
Education and research
Medical service, health and social security and nursing care
Other public services
Business services
Personal services
Office supplies
Activities not elsewhere classified
Consumption expenditure outside households (column)
Consumption expenditure (private)
Total emissions

Source) IOTEA 1995 and 2000

22

Table 26: CO2 emissions by energy goods in 2000
Energy goods
Limestone
Fly ashBlast furnace slag
Converter slag
Electric furnace slag
Coking coal
Steam coal
Crude petroleum
Natural gas
LNG
Gasoline
Jet fuel oils
Kerosene
Light oils
Heavy oil A
Heavy oil B and C
Naphtha
LPG (liquefied petroleum gas)
Oil produced by conversion
Hydrocarbon oil
Hydrocarbon gas
Petroleum coke
Coke
Coke oven gas
Blast furnace gas
Converter furnace gas
Electric furnace gas
Tar
Crude benzene
Pig iron
Crude steel (converters)
Crude steel (electric furnaces)
Pig iron scrap
Steel scrap
Electricity
Private power generation
Gas supply
Steam and hot water supply
Black liquor
General waste
Scrap wood
Animal and plant residues
Paper scrap
Wood waste
Waste textile
Waste oil
Waste plastic
SludgeWaste tire
Blast furnace dust
Used paper
Methane gas
Total

Emissionst-CO2
79,476,080
0000
178,048,012
192,810,593
22,771,945
6,117,678
144,953,340
134,497,181
27,166,966
73,053,949
114,576,169
80,968,073
133,921,818
2,547,629
55,564,072
0
7,224,162
36,418,264
14,176,152-579,939
0000-4,311,449-1,759,403-319,725-833,728-337,317
190,924
399,3380015,7260
17,259,665
22,498,257
449,4980
1,527,301
4,932,940
02,688,401
2,570,859
5,874,103
693,849-1,339,086
0
1,420
1,353,913,717

Source) IOTEA 2000

23

5. Application
5.1 Introduction
For a case study application of the IOTEA, we focused on Solar Power Satellites (SPS)
as a future alternative power generation technology. SPS technology involves a satellite
carrying photovoltaic (PV) panels in geostationary orbit (GEO) that continuously
generates electricity independent of the weather or time of day and transmits this power
to the Earth’s surface. This study measured the CO2 emissions from the latest SPS
technology — multi-bus tethered-SPS presented by Sasaki (the Japan Aerospace
Exploration Agency, JAXA) — using the IOTEA; several previous types of SPS were
included for comparison. The results revealed that the CO2 emissions from multi-bus
tethered SPS per unit of energy generated is a little more than that from a nuclear powersystem. However, the generated emissions are much less than an LNG-fired powersystem or a coal-fired energy system. Hence, we concluded that the latest SPS iscurrently one of the most effective alternative technologies for future CO2 reduction inelectric power generation.
5.2 Basic Concept of SPS
The PV cells have been receiving increasing attention as a means of electricity
generation that produces no CO2, NOx, or SOx pollution. However, because solar
energy generation is impossible at night and the poor efficiency during cloudy weather,stable electricity generation is difficult. However, if solar panels are launched into space,
they can produce continuous power independent of the weather or the day-and-nightcycle. The solar power satellite (SPS) concept is very simple: a satellite carrying PV
panels in GEO generates electricity and transmits it to the Earth’s surface.
The basic concept of SPS was first published by Glaser (1968); the US
Department of Energy (DOE), and the National Aeronautics and Space Administration(NASA) published a reference system in 1978, which is referred to as the ―DOE/NASAreference system‖ in this paper. Although the reference system was published more than
30 years ago, no other equally detailed system including ground facilities and spacetransportation system has been proposed since then; therefore, it remains therepresentative plan for future SPS systems.
Figure 2 shows the concept of the DOE/NASA reference system. The satellite
is shown in the upper part: it has a rectangular structure 10 km long by 5 km wide and
300 m deep. It carries PV panels over its surface and transmits the generated powerfrom the 1-km diameter antenna using high-frequency microwaves. The lower halfshows the rectenna on the Earth, which receives and rectifies the microwaves from the24satellite; it is elliptical in shape and has dimensions of 13 km by 10 km. Eachsatellite-rectenna pair has an output of 5 GW, and the reference system is comprised of
60 such satellites. The total annual output of electric energy has been estimated to be
2,628 billion kWh.

5km

Solar Power Satellite
PV panel

10km

Geostationary Orbit
36,000km

antenna
1km

MicrowaveElectric power
5GW

Rectenna

Earth’s Surface

Diameter; 10km

Figure 2: DOE/NASA reference system
Source) DOE/NASA (1980) SPS-FY79 Program Summary

The SPS concept of the DOE/NASA reference system is very clear, but it may be toolarge in scale for construction; therefore, smaller types of SPS have been presented by
the Institute for Unmanned Space Experiment Free Flyer (USEF), the New Energy andIndustrial Technology Development Organization (NEDO) and JAXA that haverelatively higher feasibility.3 In this study, we focused on the new multi-bus tethered
SPS that was developed by Sasaki (2006a, 2009).

3

See the New Energy and Industrial Technology Development Organization (1994), Sasaki et al. (2004,
2006a, b).

25

Bus system
Tether2～10kmPV Panel

Microwave

Multi - module.
･Cell efficiency; 35%･Upper panel:2.8GW･Lower panel:2.5GW･On the Earth:1GW

One module in Multi-BusTethered SPS

Figure 3: Features of multi-bus tethered satellite
Note) This technology presented by Sasaki (2006a, 2009)

Figure 3 shows the satellite structure of the multi-bus tethered SPS; the new
SPS system has two features. First, the satellite has a multi-module structure, and thetethers link the bus system with a PV panel in each module. Second, each module itself
functions as an electric power generator. The attached PV panel has a high power
conversion efficiency of 35%, and the total electric power generated by 625 modules is
2.8 GW in the upper panel and 2.5 GW in the lower one.4 The generated electricity is
charged by a battery, controlled to 1.36 GW and changed to microwave beams; themicrowave is then transmitted to the rectenna, which receives and rectifies the
microwaves and supplies 1 GW of electricity to industries and households.

4

The current conversion efficiency of space solar cells has not yet reached 35%.

26

Satellite

Geostationary Orbit
36,000km
PV panel
2.5km ×2.5km

Upper:2.8GW
Lower:2.5GW

Low Earth Orbit

Orbital Transfer Vehicle（OTV）
Payload; 50ｔt
Propellant；LAr, 30t
1unit;145t
Total：171unit, 600 round trips

Microwave

Electric power

1GW
Rectenna
Diameter;3.5km

Reusable Launch Vehicle（RLV）
Payload ：50 t
Propellant；LH2,250t, LOX,1,500t
1unit;2,000t
Total:14unit,1000 round trips

Earth’s Surface
Figure 4: Construction on multi-bus tethered satellite- Key Items
Note) This Picture was drowned by authors based on Sasaki (2006a, 2009) and the viewpoint ofcalculation of CO2 emissions from SPS.

We then proceed to the SPS construction process in Figure 4, which is deeply
related to the calculation of the CO2 emissions. First, the Reusable Launch Vehicle(RLV) carries the Orbital Transfer Vehicle (OTV) and satellite to low-earth-orbit; theOTV then carries the satellite to geostationary orbit; finally, the satellite deploys
automatically, and the SPS satellite is completed when the 625 modules are connectedto each other. We discuss the RLV and OTV structures in more detail here.
The total mass of the RLV is 2,000 tons; it is comprised of the payload (50tons), structure (200 tons), liquid oxygen (LOX) (1,500 tons), and liquid hydrogen(LH2) (250 tons); the latter two serve as propellants. Fourteen RLVs make 1,000 roundtrips in total.5
5

Total mass-payload ratio was assumed to be 2.5%, which is very high and a future target. The present
ratio is about 1.5%.

27

The OTV has 2,151 kW of PV panels which ionize liquid argon (LAr) for
space propulsion. The total mass of the OTV is 145 tons, which is comprised of the
payload (50 tons), structure (54 tons), PV panels (22 tons), and liquid argon (LAr) (30tons, round trip). One hundred seventy-one OTVs make 600 round trips in total.
5.3 The model
The CO2 emission that would be produced by constructing and operating the SPS
system is estimated using the IOTEA 2000, which was presented in the first part of thispaper. The input-output model for environmental analysis based on open input-output
model is given by;
CO2k = C(I - A)-1 fk
C: CO2 emission coefficient matrix (diagonal)(1)(I - A)-1: Leontief inverse matrix
fk: final demand (FD) vector of kth item of the SPS system(e.g., k = 1, satellite; k = 2, OTV; k =3, rectenna ;…)CO2 k: CO2 emission of kth item of SPS system.
C on the right-hand side of equation (1) is derived in the first part of this paper,
calculated by (CO2 emission) /(domestic production) in each sector and (I - A)-1 can becalculated from the official 2000 Input-Output Table; therefore, we have to determine
the FD vectors for each item such as the satellite, OTV, RLV, rectenna, propellant (LAr,
LOX and LH2), and PV panel, as shown in Figure 4, to solve for CO2k.
Figure 5 shows the basic procedure for determining an FD vector, using thesatellite as an example. First, the unit price and amounts of material inputs are gathered;second, these are linked according to the Input-Output Table classification; finally, thetrade and transport margins are added.

28

①Material Input Information(e.g. Satellite)
Resource
Requirements
silicon transistor
silicon diode
CPU
DRAM
・
・
・
③Add Margin
I-O
Classification
semiconductor devices
semiconductor devices
integrated circuits
integrated circuits
・・・
trade and transport margin②I-O sector

Material
Input

Unit Price

a
b
c
d
・
・
・

p_a
p_b
p_c
p_d
・
・
・

I-O
Classification
semiconductor devices
semiconductor devices
integrated circuits
integrated circuits
・・・

Prices
a×p_a
b×p_b
c×p_c
d×p_d
・
・
・

Prices
a×p_a
b×p_b
c×p_c
d×p_d
・
・
・
m1
m2
・
・

Figure 5: Procedure to determine FD vectors
Note) Main data source of FD vectors estimated are DOE/NASA (1980), Society of Chemical Engineers(1995), Yearbook Machinery Statistics, Unit price information in Input output databases, Naruo etal.(1996) and Sasaki(2006a,2009) etc.

Here, we summarize the basic information to determine the FD vectors of the SPS total
system.
Satellite: A satellite needs the following electronic components per square
meter: 4 silicon transistors, 68 field-effect transistors, 4 diodes, 4 MUPs, 4 DRAMs, 8chip resistors, 8 tantalum electrolytic capacitors, 1 m2 multilayer printer boards, and 4lithium ion batteries. Each satellite is comprised of 4,400 tons of rolled and drawn
aluminum products and 45 tons of tether. Each unit price is from the 2000 Yearbook of
Machinery Statistics and the table on domestic products by sector and commodity of the2000 Input-Output Table.
OTV: The unit price of LAr in OTV is based on the annual average price in the
Economic Research Association (2000). The OTV structure was estimated from Sasaki
and Yamagiwa (2000), the cargo orbit transfer vehicle (COTV) developed by
DOE/NASA (1980), the table on domestic products by sector and commodity, and the
airplane activity vector in the 2000 Input-Output Table.
29

RLV: The unit price of LH2 is based on estimates from Naruo et al. (1996), andthe price for LOX is from the 2000 Yearbook of Machinery Statistics. The RLV structure
was estimated from the heavy lift launch vehicle (HLLV) developed by DOE/NASA(1980), the table on domestic products by sector and commodity, and the airplane
activity vector in the 2000 Input-Output Table.
Rectenna: The rectenna cost structure, its installation cost, and the number ofdiodes and antennas are estimated based on another type of rectenna from DOE/NASA(1980), large-scale solar power systems on the ground (e.g., Society of Chemical
Engineers 1995, Kato et al. 1994, Nomura et al. 1995), and the electric power facilities
construction activity in the 2000 Input-Output Table. Inverters and relay switches are
estimated from work done by the Society of Chemical Engineers (1995), Kato et al.
(1994) and Nomura et al. (1995)
PV: PV that are attached to the satellite and OTV are assumed to havehigh-conversion efficiency, be resistant to radiation, and workable except for the coverglass, which is similar to current copper indium gallium diselenide (CIGS) thin-film PV
cells; however, it is difficult to obtain the structural information for this particular type.
Therefore, we use recent solar cell activity estimated by Nakano (2006) under the strong
assumption that solar cell activity does not change according to the conversion
efficiency.
5.4 Overview of CO2 Emissions
In this section, we describe the main results for estimates of CO2 emissions from SPS
construction. Table 27 shows that the released CO2 would be 11 million tons. The
largest amount is released from the production processes of LOX and LH2 in RLV,
which account for 60% of the total CO2 emissions. The second largest amount comesfrom the PV attached to the satellite and the OTV in total, which account for 22% of thetotal emissions.

30

Table 27: CO2 emissions from SPS by items
Item
Satellite
OTV

RLV

kiloton share(%)
1116.910.4
2194.9
20.4
75.3
0.7
61.0
0.6
152.3
1.4
47.0
0.4
6406.9
59.6
693.4
6.5
10747.7
100.0Structure
PV
Structure
LAr
PV
Structure
LOX, LH2

Recttna
TotalNote) OTV: Orbital Transfer Vehicle, RLV: Reusable Launch Vehicle, PV: Photovoltaic cell, LAr:
Liquid argon, LH2: Liquid hydrogen, LOX: Liquid oxygen. Figures are calculated by eq. (1).

Table 28 shows the four highest-ranking sectors of CO2 emissions in the SPS
system. For LH2 and LOX in RLV, which induced the largest emissions according toTable 27, the production process of these propellants, such as compression and cooling,
require large amounts of electricity; therefore, electricity-related sectors were ranked
high as a result. In short, Table 28 shows that each item in the SPS system requires
various kinds of materials directly, but direct and indirect CO2 emissions are mainly
induced by electrical power generation.

31

Table 28: CO2 emissions from SPS by sectors(a) satellite (structure)

Share(%) (b) OTV (structure)

Share(%)

1 electricity
2 private power generation
3 pig iron
4 coal productotherstotal

35.4 electricity
10.4 private power generation
6.2 pig iron
5.5 coal product42.5 others
100.0 total(1,117 kilotons)

32.7
13.0
6.5
5.7
42.1
100.0
(75 kilotons)

Share(%) (d) RLV (structure)

Share(%)

73.1 electricity
7.9 private power generation
3.7 coal product2.2 pig iron13.2 others
100.0 total(61 kilotons)

30.9
15.1
7.8
7.7
38.5
100.0
(47 kilotons)(C) OTV (LAr)
1 electricity
2 compressed gas and liquefied gas
3 private power generation
4 coal productotherstotal(e) RLV (LH2, LOX)

Share(%) (g) Rectena

1 electricity
2 road freight transport
3 compressed gas and liquefied gas
4 private power generation
otherstotal

63.9 pig iron
7.5 electricity
6.7 private power generation
3.6 coal product18.3 others
100.0 total(6,407 kilotons)(h) PV (satellte and OTV)
1 electricity
2 private power generation
3 coal product4 pig ironotherstotal

Share(%)
24.0
23.2
8.7
7.9
36.2
100.0
(693 kilotons)

Share(%) (i) SPS total
47.6 electricity
10.7 private power generation
7.5 road freight transport
4.7 coal product29.5 others
100.0 total(2,347 kilotons)

Share(%)
54.4
6.3
5.2
4.1
30.0
100.0
(10,748 kilotons)Note) Figures are calculated by eq. (1).

5.5 Comparison of CO2 Emission.
Lastly, we compare the CO2 emissions of the multi-bus tethered SPS system withdifferent kinds of electricity generation systems.
First, the annual energy production of SPS can be calculated as:
1 GW × 24 h × 365 day = 8,760 GWh.
Furthermore, if we assume a lifetime is 40 years, and the CO2 emissions from SPS
construction is 10,748 kilotons, the CO2 emission per kWh can be estimated as:32

10,748 kilotons/40 years/8,760 GWh × 1000 =30.7 g CO2/kWh.

g-CO2 / kWh

1,000

975

900

Operation

Construction

800
742
608

76

100

58

53
22

20

49

31

11

Several Types of SPS

Figure 6: CO2 emissions per kWh of energy production
Notes) 1) Figures for Coal, Oil, LNG, Nuclear, and PV1 were estimated by Hondo (2000). 2) Figure forPV2 is a recalculation of Nakano (2006) using eq. (1). 3) Figures for several types of SPS are estimatedby our group; DOE/NASA and DOE/NASA Breeder are from Asakura et al. (2002), NEDO from Ohashi
et al. (2001), USEF from Asakura et al. (2003). 4) Lifetime assumption for multi-tethered satellite
system: 40 years.

Figure 6 compares the CO2 emissions per kWh of electrical energy produced
by several types of existing electric power generation systems and the SPS systems.
When comparing SPS systems, the DOE/NASA reference system has the lowest CO2
emissions per kWh, as it has a very efficient transport system; i.e., the total
mass-payload ratio is relatively higher than those for NEDO, USEF, and multi-bus
tether, which means relatively less propellant is needed.
When the CO2 emissions of the multi-bus tethered SPS is compared withexisting electric power generation systems, the SPS CO2 emission is a little higher thanthat of nuclear power; however, it is much lower than that of fossil fuel electric power
33

generation, 1/30 of coal, 1/24 of oil, and 1/20 of natural gas.
This study clearly shows that construction of the SPS system releases large
amounts of CO2; however, the CO2 emissions per kWh for SPS are much lower thanthat of existing power plants. In addition, our recent calculations show that the CO2 per
kWh of SPS is in double digits even when the structures are different, such as
DOE/NASA, NEDO, USEF, and multi-bus tether.
Further investigation is required on how to reduce CO2 emissions by ―solar
breeding,‖ in which installed SPS supplies electricity for producing further SPS or
liquid fuel. This is a very challenging research target, and we will try to further develop
the next stages.
6. Concluding remarks
This paper is a report on the estimation method for the IOTEA 2000 and its application
study. Energy and economy statistics are considerably developed in Japan comparedwith other countries. This has led to the detailed estimation of the Input-Output Table.
The amount of information for energy and environmental analyses is increasing. For
instance, we can estimate the energy consumption for co-generation and the recycling
sector in the Input-Output Table. However, at the same time, the Structural Survey ofEnergy Consumption in Commerce and Manufacturing has already become out of date.
The IOTEA provides information on the detailed structure of CO2 emissions,which is necessary to assess ecofriendly technologies and to introduce measures against
global warming. Hence, ensuring that the necessary statistics are up-to-date andcontinuously estimating the IOTEA is a major challenge. Effective utilization of theSurvey of Energy Consumption and Comprehensive Energy Statistics should be
discussed.
Acknowledgements
We thank Susumu Sasaki (Japan Aerospace Exploration Agency, JAXA) and Yoshihiro
Naruo (JAXA) for providing us technical information on the SPS system. Our thanks
are also due to Kanji Yoshioka (Keio University) and Hitoshi Hayami (Keio University)
for many valuable comments and suggestions on this study. The authors are solely
responsible for any errors.

34

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