English Summary

Study of Potential for the introduction of Renewable Energy
As a 2009 project, the Ministry of Environment appointed Ex Corporation Environmental & Urban
Planning, Research and Consulting, Itochu Techno-Solutions Corporation, Pacific Consultants Co., Ltd.,and Asia Air Survey Co., Ltd. to carry out an study entitled “Study of Potential for the introduction of
Renewable Energy” (hereinafter referred to as the “Potential Study”). The details of this study are
discussed here.
In this Potential Study, energy resources which can be estimated theoretically but do not take into
account various limiting factors (such as land application or application technology) are defined as“potential”; whereas, feasible energy resources where various limiting factors concerning energy
collection (extraction) and application are taken into consideration and which are estimated after
creating a scenario (assumption) for limiting factors are defined as “introduction potential”. Although theso-called targeted value are set within the introduction potential, the introduction potential should be
reviewed accordingly since limiting factors such as economical efficiency may change.

1.

Photovoltaic (PV) power generation

According to the “Photovoltaic (PV) Roadmap Toward 2030 (PV2030+)” compiled by the New Energy
and Industrial Technology Development Organization (NEDO) in June 2009 (hereinafter referred to as
the “PV2030+”), the potential of photovoltaic power generation, for which the latent capacity physicallyfeasible for installation in a building or low, unused sites is compiled, is estimated to be 7.98 billion kW
in total (of this, 7.29 billion kW is for unused land) (in the PV2030+, it is referred to as “scale feasible tophysically introduce”)1). In case of PV power generation, since the factor for locally uneven distribution
is small, the potential is often described as the grand total of products from a number of facilities andareas by setting basic unit by facility (for example, 4kW/building). Therefore, in the PV2030+ this isestimated in such a manner.
However, for non-residential buildings, roof types or shape of roofs are complicated and sunlight
conditions vary significantly. In addition, equipments such as air conditioning units are installed
outdoors in many cases. Hence, in the Potential Study, for non residential buildings, an investigation ofbasic unit based on sample drawings was carried out. In this investigation, based on the following
scenario, the areas where PV cells can be installed was estimated and after assuming the unit output perunit areas as 0.067kW/m2, the introduction potential was also estimated.

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The installation area over 150m2/site, over 20m2/site or over 10m2/site respectively cannot be
secured as area for installation
the range where each equipment or structure exists;
the range where power generation cannot be expected due to limited sunlight hours andPlaces without roof.
The result, as illustrated in table 1, was in the range of 2,400 to 56 million kW.
Table 1: Introduction Potential of PV Power Generation on Non-Residential Buildings
Classification Facility Category

Introduction Potential(10,000 kW)

PublicGovernmental buildings

30 to 150

Schools

740 to 1,100

Cultural facilities (such as

100 to 390

community centers)
Medical and welfare

10 to 110

institutions
Michi-no-eki (Roadside

10 to 260

stations)
Water supply and sewer

60 to 80systems
Industry

Subtotal

950 to 2,100

Plants1,500 to 3,400

Power stations, etc.

1 to 5

Subtotal

1,500 to 3,400

Total

2,400 to 5,600

The introduction potential estimated is within the introduction potential of the PV2030+ where theintroduction potential of PV power generation for buildings other than residences was estimated to be
8.88 to 91.56 million kW. The result also supported evidence that the ratio of plants, businessestablishments or schools tended to be high. Accordingly, the importance of policies to promote theinstallation of PV power generation to such facilities was suggested.
In the Potential Study, suitability of low and unused land suitable for “megawatt solar systems” which
are planned or have been constructed was also examined. As indicated in the findings in Table 2, it wasestimated to be in the range of 76 to 94 million kW. By combining the potential of non-residentialbuildings, and low and unused land, the total is estimated to be in the range of 100 million to 150 million
kW.

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Table 2: Potential for PV Cell Installation at Low and Unused Lots
Lot Classification

Introduction Potential(10,000 kW)

Abandoned cultivated

6,700

land (*)
Industrial estates (sold160 to 370

2

in lots) (* )Final disposal sites

310

3

390 to 2,000

Total

7,600 to 9,400

Others (* )(*) It is assumed that for land such as ones being used for forestry or wild land etc that cannot bereclaimed as farm land (because maintaining the physical conditions to reclaim as farm land is very
difficult), photovoltaic facilities are installed in parts of land not designated as farm land and land
located within designated farm lands but not suitable for farming purposes.
(*2) It is assumed that photovoltaic facilities are installed within a fixed area after subdivision.
(*3) Based on “Research and Development on PV Power Generation Application System andPeripheral Technologies, Research and Development on Diversified Installation Methods” (1995) ascompiled by the Central Research Institute of Electricity Power Industry (CRIEPI).
In the Potential Study, a questionnaire survey was conducted for prefectures, ordinance-designed cities,
major cities, special cities and special wards (170 municipalities in total) that enquired about conditions
for setting goals when introducing to public facilities. From the results, it was learnt that fifteen (15)municipalities set numerical targets for the introduction to public facilities and three (3) municipalities
had prepared introduction goals beginning FY2020. However, introduction goals remain under 20% of
the introduction potential for public facilities as described earlier and hence further promotion andencouragement of the introduction should be made.

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2. Wind power generation(i) Onshore wind power generation
The resource for onshore wind power generation is often predicted based on the assumption of installinga certain density of wind turbines under favorable wind conditions. Based on the wind conditions map“WinPAS” developed by the Itochu Techno-Solutions Corporation, the Potential Study estimated theresource assuming the installation of wind turbines at sites that are above 80m elevation and have anannual mean wind speed greater than 5.5m/s and the installation is in the range of 10,000 kW/km2. As aresult, the land wind energy resource was estimated to be 1.4 billion kW. The resource for onshore wind
power generation within national and quasi-national parks is 17 million kW, which is only 12% of thetotal.
For the above-mentioned resource map, the resource for onshore wind power generation was projectedbased on the following scenario by estimating areas feasible for wind turbine installation by overlaying
on geographic information system (GIS):
annual mean wind speed is over 7.5 m/s, over 6.5m/s or over 5.5 m/s;
altitude less than 1,000m;
maximum tilt angle of less than 20 degrees;
distance less than 10km from roads larger than 3m;
distance from residential area more than 500m;
prohibited development areas in protection forest areas, special protection zones and Class 1
special zones within national and quasi-national parks, wilderness areas, nature conservation
areas, state-designated wildlife protection areas and world natural heritage sites andprohibited development areas in fields, building lots, lots used as trunk transportation lines,
rivers and wetlands, or golf courses.
As shown in Table 3 and Figure 1, the potential of onshore wind power was estimated to be in the rangeof 70 million kW to 0.3 billion kW.
The results show that annual mean wind speed has a direct effect on capacity factor and generating cost.
For example, the annual mean wind speed of 7.0m/s is equivalent to a capacity factor of 27% 2). Basedon the findings of the Potential Study, it is possible to estimate the potential in proportion to generating
cost.

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Wind Power Generation■ Annual mean wind speed (above 80m elevation) over 7.5 m/s■ Annual mean wind speed (above 80m elevation) over 6.5 m/s■ Annual mean wind speed (above 80m elevation) over 5.5 m/s

Figure 1: Onshore Wind Power Generation Potential Distribution

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(ii) Offshore wind power generation
The resource for offshore wind power generation was also estimated assuming the installation of windturbines at sites with an elevation above 80m above sea level and with an annual mean wind speed ofmore than 6.5m/s in a range of 10,000 kW/km2 based on the WinPAS. From the results, the resource foroffshore wind power generation was estimated as 7.7 billion kW.
For the above-mentioned resource map, the potential of offshore wind power was estimated based on thefollowing scenario and by estimating areas feasible for wind turbine installation by overlaying on
geographic information system (GIS):
annual mean wind speed is over 8.5m/s, over 7.5 m/s or over 6.5m/s;
distance from coast line less than 30km;
water depth less than 200m (50m for fixed type, between 50m and 200m for floating type) andprohibited development area in marine park zones within national and quasi-national parks.
As shown in Figures 2 and 3, the potential for sea-based fixed type and floating type wind power
generation were estimated to be in the range of 5.1 million kW to 310 million kW and the range of 56
million kW to 1.3 billion kW respectively.
With respect to offshore wind power generation, promotion of technological development for practicalapplication is very important. In particular, presently the floating type is in research and development
stage globally and it is necessary to develop wind turbines that can withstand severe weather conditions
such as typhoons prevalent in Japan.

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Offshore Wind Power Generation (Fixed Type)■ Annual mean wind speed (above 80m elevation) over 8.5 m/s■ Annual mean wind speed (above 80m elevation) over 7.5 m/s■ Annual mean wind speed (above 80m elevation) over 6.5 m/s

Figure 2: Offshore Wind Power Generation Introduction Potential Distribution (Fixed Type)Offshore Wind Power Generation (Floating Type)■ Annual mean wind speed (above 80m elevation) over 8.5 m/s■ Annual mean wind speed (above 80m elevation) over 7.5 m/s■ Annual mean wind speed (above 80m elevation) over 6.5 m/s

Figure 3: Offshore Wind Power Generation Introduction Potential Distribution(Floating Type)S-21

A characteristic feature of the introduction potential of wind power generation is that the local
distribution is extremely uneven. So the simple potential for wind power generation at supply areas ofelectric power companies in Hokkaido, Tohoku and Okinawa were estimated to exceed the generating
system capacity of each electric power company. Change in generated energy from wind power
generation to some extent cannot be avoided due to change in weather conditions. Moreover, theinterconnection of line capacity between electric power companies is limited. Hence these issues will
become limiting factors and hence the capacity that can be assigned to wind power generation is limited
to a portion of the local electricity demand. Further, it is also difficult to install windmills in all areas in
the range of 10,000 kW/km2 and hence the realistic potential will be lower than the potential indicated inTable 3. The Japan Wind Power Association prepared an introduction roadmap by setting a long-term
introduction goal based on the scenario that wind power generation will provide 10% of the electricity
demand nationwide, on the assumption that electric power companies will interconnect to some extent
and windmills will be installed in the 1,500 to 1,650kW/km2 2) range.
From the results of the roadmap study, although the distribution of the potential of wind power
generation could be obtained from GIS, when establishing project sites, it needs to be stated that local
information which cannot be grasped in the GIS level should be accumulated through other means.

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3.

Medium and small-scale hydro power generation

Although the term “medium and small-scale hydro power generation” has not been strictly defined, theterminology used here will take into consideration the cost of approved projects for medium andsmall-scale hydro power generation development as conducted by the Ministry of Economy, Trade andIndustry, medium and small-scale hydro power generation of less than 30,000kW output.
Although the Study on Potential Hydroelectricity of Unused Fall Head 5) conducted by the Agency for
Natural Resources and Energy is a study on undeveloped hydro power generation potential, with respect
to small-scale studies, due to the technical nature of questionnaire surveys, there is a risk that someresults may be lower than the actual condition due to the degree of interest of those who responded tothe survey. Consequently, in the Potential Study, with respect to water channel alignment data (including
altitude data) compiled by the Geographical Survey Institute, catchment flow quantity data anddistribution channel water intake data compiled by the Ministry of Land, Infrastructure, Transport andTourism and prefectures, throughout the entire country was divided into 319 watershed blocks,
maintained water volume and water intake flow quantity were taken into account, and the usable water
volume was set up. In addition, assuming the installation of hydroelectric power stations at riverjunctions with catchments within blocks (180,000 locations in total), the usable water volume wasestablished. The annual electric power generation of P (kWh) was estimated assuming 72% generating
efficiency as follows:
P (kWh) ＝ 9.8×0.72× assumed annual usable water volume at a generating plant /3,600× effective
head at the assumed generating plant.
The construction cost for each assumed electric power station can be estimated by this annual electric
power generation, horizontal water conveyance distance and fall head. The potential was estimatedassuming the installation of hydroelectric power stations at sites where construction unit cost would beless than ¥2.6 million/kW (installed capacity).
For the above-mentioned potential map, the introduction potential was estimated based on the following
scenario and by estimating areas feasible to install windmills by overlaying on the geographic
information system (GIS):
construction unit cost less than ¥500,000/kW, less than ¥1 million/kW, less than ¥1.5 million/kWor less than ¥2.6 million/kW;
distance less than 10km from roads larger than 3m;
maximum tilt angle of less than 20 degrees andprohibited development in special protection zones and Class 1 special zones within national andquasi-national parks, wilderness areas, nature conservation areas, state-designated wildlife
protection areas and world natural heritage sites.

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From the results shown in Table 3 and Figure 4, the introduction potential of hydraulic power generation
was in the range of 0.8 to 1.5 million kW.
Since the construction unit cost of small-scale hydro power generation is directly related to electricity
sales prices for commercialization, based on the findings of the Potential Study, the introduction
potential corresponding to the electricity sales prices can be estimated.
Local distribution is also extremely uneven even in the introduction potential of medium and small-scalehydro power generation. Accordingly, the potential was estimated to be concentrated at electricity supply
areas in Hokuriku, Tokyo, Chubu and Tohoku.
From the findings of the roadmap, although the potential distribution of medium and small-scale hydropower generation could be obtained from GIS data, it is essential to note that some relevant data, such as
fresh-water fisheries rights, have not yet been accumulated. Furthermore, hydro power generation has
already been developed at some locations, which is considered to have introduction potential. On theother hand, in cases where water intake for utilization for power generation exists in areas upstream
from the flow rate observatory, the flow rate may be underestimated. In addition, although it is assumed
that only a single power station will be constructed at a large-scale water channel section of more than
10km, the potential may increase if it is divided allowing for multiple stations. Further, agricultural
water channels are not included in the calculation and the standard construction cost is regarded to be aprerequisite for calculating the potential as a threshold value. However, since some locations are actuallylarger and have been commercialized, the details for these should continue to be examined.
In this Potential Study, the potential and introduction potential of water supply, sewerage and water forindustrial use have been examined andthe potential and industrial potential were respectively

estimated to be approximately 180,000kW and a range of 140,000 to 160,000kW.

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Medium and Small-scale Hydraulic Power Generation■ Less than 2.6 million construction unit cost/kW■ Less than 1.5 million construction unit cost/kW■ Less than 1 million construction unit cost/kW■ Less than 0.5 million construction unit cost/kW

Figure 4: Medium and Small-scale Hydro Power Generation Introduction Potential Distribution

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4.

Geothermal power generation

In this Potential study, potential was estimated by using information based on geothermal resources
density distribution (greater than 150ºC applicable for flash steam generation, 53ºC to 120ºC applicablefor Carina cycle generation) prepared by Murakami et al. of the National Institute of Advanced
Industrial Science and Technology (AIST) and by newly preparing a geothermal resources density
distribution for Rankine cycle generation applicable in 120ºC to 150ºC and by assuming the constructionof geothermal power stations at locations with resources density greater than certain level (for example,
over 10kW/km2 at over 150ºC). As a result of the estimation, the potential was estimated to be 24
million kW at over 150 ºC, 1.1 million kW at 120ºC to 150ºC, and 8.5 million at 53 to 120ºC
respectively. The potential for national and quasi-national parks with respect to over 150ºC was 19
million kW, which accounted for 83% of the total.
For the above-mentioned potential map and the following scenario, the introduction potential for casesof temperature over 150 ºC and a range of 120ºC to 150 ºC were estimated. Areas feasible for the
installation of power stations was estimated through overlaying on the geographic information system(GIS) and a scenario where the power generation cost was designated as a parameter was set.
Introduction potential for over 150 ºC and a range of 120ºC to 150 ºC
the distance from residential areas is over 100m;
prohibited development in special protection zones and other special zones (Class 1, Class 2 andClass 3) within national and quasi-national parks, wilderness areas, nature conservation areas,state-designated wildlife protection areas and world natural heritage sites andprohibited development on lots used for trunk transportation routes, other lots, rivers andwetlands, and sea waters.
Introduction potential for 53ºC to 120ºC:
prohibited development in special protection zones and Class 1 special zones within national andquasi-national parks, wilderness areas, nature conservation areas, state-designated wildlife
protection areas and world natural heritage sites.
prohibited development on lots used for trunk transportation routes, other lots, rivers andwetlands, and sea waters.
From the results shown in Table 3 and Figures 5 to 7, the introduction potential of geothermal power
generation was 1.1 to 2.2 million kW for over 150ºC, 8,000 to 210,000 kW for 120ºC to 150ºC and lessthan 7.4 million kW for 53ºC to 120ºC.
Since resources density has a high degree of correlation with generating cost, it is possible to estimate
the introduction potential corresponding to generating cost based on the findings of the Potential Study.

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With respect to the introduction potential of thermal power generation for over 150ºC, local distribution
is extremely uneven and one third (1/3) of the potential exists in Hokkaido and power supply areas ofKansai, Chugoku, Shikoku and Okinawa electricity have very little potential for geothermal power
generation. However, as was seen in wind power generation, there are no areas where the estimatedvalue was expected to exceed the generating facility capacity of an electric company. Locally uneven
distribution was recognized to be somewhat relaxed in areas with temperature range of 53ºC to 120ºC.
In addition to the points mentioned above, introduction of hot spring power generation at pre existing
hot springs and other naturally occurring hot springs was considered. There is a less degree of risk in thedevelopment of hot spring power generation to generate power by utilizing existing hot springs, and its
potential is estimated to be 720,000kW for locations with capacity of over 30kW/location3). Althoughgenerating cost is considered to be less than ¥36/kW, compared with the generating cost of flush steam
generation, economic side could be a challenge and hence technologies for lowering the cost need to be
developed.

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Introduction Potential with over 150ºC■ Generating cost: less than ¥20/kWh
Density Category: over 1,020kw/km²■ Generating cost: less than ¥16/kWh
Density Category: over 2,760kw/km²■ Generating cost: less than ¥12/kWh
Density Category: over 7,490kw/km²

Figure 5: Geothermal Power Generation Introduction Potential Distribution (over 150ºC)

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Introduction Potential with over 120 to 150ºC■ Generating cost: less than ¥48/kWh
Density Category: over 7kw/km²■ Generating cost: less than ¥36/kWh
Density Category: over 88kw/km²■ Generating cost: less than ¥24/kWh
Density Category: over 1,050kw/km²

Figure 6: Geothermal Power Generation Introduction Potential Distribution (120ºC to150ºC)

Introduction Potential with over 53 to 120ºC■ Generating cost: less than ¥48/kWh
Density Category: over 17kw/km²■ Generating cost: less than ¥36/kWh
Density Category: over 164kw/km²■ Generating cost: less than ¥24/kWh
Density Category: over 1,590kw/km²* No area is applicable to less than generating
cost of ¥24/kWh and density category of over
1,590kw/km².

Figure 7: Geothermal Power Generation Introduction Potential Distribution (53ºC to120 ºC)

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Acknowledgements
During the course of this Study, a part of the Study was re-commissioned to the Nagai Lab, the Collegeof Industrial Technology at Nihon University, the National Institute of Advanced Industrial Science andTechnology (AIST), E & E Solutions Inc., and NTT GP-ECO Communication, Inc. In addition, thefollowing specialists provided advice and instructions as external advisors. We would like to take thisopportunity to express our sincerest gratitude to these individuals.
(1) Yoshikazu OKABAYASHI: Secretary General, Japan Photovoltaic Energy Association(2) Tetsuo SAITO: Chief of Planning Section, Japanese Wind Power Association(3) Masaru NAKAJIMA: Secretary General, Japanese Association for Water Energy Recovery(4) Hiroki HONDO: Associate Professor, Graduate School of Environment and Information Sciences,
Yokohama National University

Sources(1) New Energy and Industrial Technology Development Organization (NEDO), Photovoltaic (PV)Roadmap Toward 2030 (PV2030+), June 2009, p115
(http://www.nedo.go.jp/library/pv2030/pv2030+.pdf)(2) Japanese Wind Power Association, Long-term Wind Power Generation Introduction Goal andRoadmap, V1.1, January 2010, p13(http://log.jwpa.jp/content/0000288882.html)(3) Yukio ETO and Hirofumi MURAOKA et al., Contribution of Geothermal Energy to 2050 Natural
Energy Vision, Journal of the Geothermal Research Society of Japan (GRSJ), 30 (3), 2008

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Table 3: Renewable Energy Potential and Introduction Potential
Unit: 10,000kW
2Wind Power Generation

OnshorePotential

Offshore(Floating
type)

Offshore(Fixed type)

140,000

770,000

Medium- andSmall-scale
Hydro Power
Generation(*)

Geothermal Power Generation (* )(Reference)
Generating Capacity ofOver 150ºC

120 to 150

53 to120

Electric Companies(FY2008)

1,800

2,400

110

850

80 to 1,500

110 to 220

0.8 to 21

0 to 740

7,000 to 30,000(bySummary
Value by
Scenario

electricity

Hokkaido

3,000 to 15,000

470 to 12,000

3,800 to 28,000

2 to 130

39 to 71

0.6 to 7

0 to 246

650

supplyTohoku2,100 to 7,400

7 to 4,400

1,000 to 18,000

14 to 410

38 to 76

0 to 50 to 194

1,680

region)Tokyo

100 to 450

32 to 2,800

640 to 5,200

15 to 220

10 to 18

0 to 1

0 to 112

6,398

Hokuriku

44 to 520

0 to 420

0 to 5,900

19 to 190

0 to 0.3

0.1 to 3

0 to 26

796

Chubu

250 to 870

0 to 1,900

110 to 1,900

16 to 270

1.2 to 5.5

0 to 1

0 to 88

3,263

Kansai

330 to 1,300

0 to 160

0 to 2,400

2 to 38

0 to 0.2

00 to 83,386

Chugoku

190 to 1,000

0 to 460

0 to 15,000

4 to 64000 to 15

1,183

Shikoku

110 to 530

0 to 390

0 to 3,800

3 to 73000 to 4666

Kyushu630 to 2,200

2 to 5,400

48 to 40,000

3 to 100

25 to 49

0.1 to 3

0 to 52

2,002

Okinawa

280 to 560

1 to 2,800

1 to 6,300

0 to 0.2

0

0

0

192

Introduction
Potential

20,2185,600 to510 to 31,000
130,000(*) Less than 30,000kW of facility capacity: water supply, sewerage and water for industrial use (approximately 180,000kW of the potential) are notincluded.
(*2) The potential of hot spring power generation is not included.

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