Energy Vol. 13, No. 3, pp. 245-251, 1988 0360~5442/88 $3.00 + 0.00 Printed in Great Britain. AU rights reserved Copyright IQ 1988 Pergamon Press plc

GEOTHERMAL ENERGY POTENTIAL AND UTILIZATION IN TURKEY

E. TASDEMIROCLU

Mechanical Engineering Department, Middle East Technical University, Ankara, Turkey

(Received 3 June 1987)

Abstract--The regional distribution of the geothermal energy potential in Turkey, recent surveys, and utilization areas are described. The present and future roles of geothermal energy and their economic aspects are discussed. ‘Ihe implications of geothermal energy exploration and utilization are noted. Recommendations are made to expand geothermal- energy development.

INTRODUCTION

Turkey is one of the countries with significant potential in geothermal energy. Resource assessments have been made many times by MTA (Mineral Research and Exploration Institute of Turkey) and TEK (Turkish Electricity Board).‘-” The data accumulated since 1962 show that there may exist about 45OOMW of geothermal energy usable for electrical power generation in high enthalpy zones. In addition, 31,000MW of geothermal energy potential is estimated for direct use in thermal applications. The regional distributions of these potentials are given in Table 1.“S12 The geothermal energy potential stored within the territory has also been estimated to be about 3.1 x ldo KJ, which equals approx. 2 x lo6 of the total energy consumption in 1986. l3

The available data are not yet believed to be sufficient for correct evaluation of the net potential. Additional investigations are being carried out and the results need to be evaluated. The aims of this paper are to provide information on recent surveys and potential assessments and to discuss the future of geothermal energy in the country.

GEOTHERMAL ENERGY ACTIVITIES

The beginnings of geothermal energy exploration in Turkey goes back to 1962. MTA, in cooperation with UNDP (United Nations Development Programme), conducted an inventory study on the distribution of hot-water springs and geothermally potential fields over the territory. 14*15 In this survey, geological, geophysical, geomorphological, and geochemical methods were used and a number of wells drilled at prospective sites.“”

In addition to the known hot-water sources utilized as balneological centers, some new areas with considerable geothermal energy potential were discovered. It was then proved that the Anatolian territory consists of a young tectonic belt and has numerous grabens, acidic volcanic activities, hydrothermal alterations, fumaroles, and more than 600 hot-water resources with temperatures changing between 20 and 100°C. Table 2 provides some information on the main

Table 1. Regional distribution of geothermal energy potential.

Estimated Capacity (KW) Region

Electrical Thermal

Aegean Sea 2,000 14,000

Black eea 200 2,100 Central Anatolia a00 5.000

East and Northeast

Ana tolia 500 4,030

Marmara Sea 1,000 6,000

Total I I

4,500 1 31,100

245

246

t NO. Lr,cation

Present * Usable Field §

Utilization lemperature,

OC Works

1.1 timer-Cepek G.B,F 70 RG,G,R,Dd,Dh

1.2 Sandlkli B*D 67 RG,G,R

2.1 Kizilcahamam B 40 RG,G,R,Dd,Dh

2.2 Cubuk 35 RG,G,R,Dd,Dh

2.3 Ayas B 43 RG,G,R

3.1 Germencik B 101 RG,G,R,Dd,Dh

3.2 Salavatli B 38 RG

3.3 Aydin H 34 RG,G

3.4 Giimiiq B 40 RG,G

4.1 Slndlrgl B 98 RG.G,R

4.2 Havran B,G RC,Dd

4.3 GonerI G.D 54 RG,G,R,Dd

4.4 Kepekler II 60 RG,G,R

4.5 Pamukcu A

5.1 Nemrut 60 RG,G

5.2 Siiphan RG,G

6.1 Seben 60 RG

7.1 Bursa B 40 RG,G,R

8.1 Tuzla B 102 :G,G,R,Dd,Dh

8.2 Kestanbol B,G 50 RG,G,R,Ihd

8.3 Hidirlar B 87 RG,G,R

9.1 Krzildere G,I,E 99 :G,G,R,Dd,Dh

9.2 Tekkehamam B,G 99 RG,G,R,Dd

9.3 Pamukkale B 56 RG,G,R,Dd

10.1 Illca B 33 RG

10.2 Dumlu B 40 RG

10.3 Pasinler B 45 RG,G,R,Dd,Dh

11.1 Eskisehir B.D.G 42 RG,G,R,Dd,Dh

12.1 Te rmal B 65 13.1 Seferihisar B,G 85 RG,G,R,Dd,Dh

13.2 BalpWfa G,B,D 62 RG,G,R,Dd

13.3 Dikili-Bergam; B 90 RG,G,R,W

13.4 Ceqme B 58 A

14.1 Mahmutlu B 70 RG

14.2 Terms B 45 RG

14.3 Karakurt El 50 A

15.1 Simav B,D 98 RG,G,R,Dd,Dh

15.2 Gediz B 78 A

16.1 Salihli B @A RG,G,R,Dd

16.2 Urganll B 78 RG,G,R

17.1 Kosakl1 B 92 RG,G,R,Dd

17.2 Acigiil RG,G,R

18.1 Siirt A

19.1 Zilan 78 RG.G

E. TASDEMIROCLU

Table 2. The primary geothermal areas and some characteristics.

Reservoir

Pemperature,

oC

105 110

150 68

Maximum

ReservoiJ' Flow . Rate, Rock

Kg/s 183

50

35

240 100

2

10

5

60

165 60

150

112

90 250

5

5f-J

30

5

110

220

73 200

250 220

150 100

100

80

80

225

150 180

80

146

215

210

150 120

36 60

1

400

50

50 20

10 5

50 10

50

62 20

34

28

10

10

10

8

5

25

20

240 20

M

P

VPL

Q1C.M

L

D

M

L

V

M,Q M

M

LB L

L

F

V,L

L

L,G

M

M

L

H

L

tNumbers before the period refer to the name of the main city as follows: 1. Afyon, 2. Ankara, 3. Aydm, 4. .Bahkesir, 5. Bitlis, 6. Bolu, 7. Bursa, 8. Canakkale, 9. Den&h, 10. Erzurum, 11. Eskisehir, 12. Istanbul, 13. Izmir, 14. Kqehir, 15. Kiitahya, 16. Manisa, 17. Nevgehir, 18. Siirt, 19. Van. Numbers following the period refer to the specific location within the territory of the city.

$A-agricultural drying; B--bathing, swimming and/or balneological center; D-district heating; E-electricity production; F-fish and other animal farming; G-greenhouse heating; I-industrial process heating.

SRG-remote sensing, geological, geochemical; G-gravity; R-resistivity; Dd-deep well drilling; Ds-shadow well drilling.

flB-hasalt; C-talc-schist; D-diabase; F-flysch; D-dry hot rock granite; L-limestone; M-marble; Q-quartzite; V-volcanic rock.

Geothermal energy in Turkey 247

248 E. TASDEMIRO~LU

hot-water resources and is based on the latest available data. “+r9 In conjunction with Table 2, the distribution of these fields over the territory is also given in Fig. 1.

Among the high-enthalpy zones, the most important, in order of importance are as follows: (a) Denizli-Ktzildere (9.1, cf. Fig. 1) which was discovered in 1968. It is the site of the only commercial geothermal power plant in Turkey with 20.4 MW gross capacity and operational start in 1984. From this system 17.8 MW of net energy input are supplied to the national interconnected power system.20,21 Waste fluid at 100°C is also used for greenhouse heating and for bleaching material in the textile industry. (b) Aydm-Germencik (3.1) was discovered after deep drillings performed in 1982. Test studies are continuing. The potential for electricity production is estimated to be about 100MW.22 (c) Canakkale-Tuzla (8.1) which was first drilled in 1982. The expected potential is about 125 MW. The area is especially convenient for agricultural utilization.3 (d) Izmir-Seferihisar (13.1) which was discovered in 1982. Construction of a 150 MW plant is planned. Besides electricity generation, its energy potential can be used for greenhouse heating and building facilities. l2 Salt can also be produced because of suitable chemical composition of the water. (e) Van-Zilan (9.1), Bitlis-Nemrut (5.1) and Bitlis- Stiphan (5.2) which were recently discovered. Dry steam production is expected. The area may have 500 MW electrical and 4000 MW thermal potential.12 (f) Nevsehir-Acigiil (17.2) where geological surveys revealed the presence of an active heat source in 1982. A hot-dry-rock technique has been considered to be best suited for electricity production.16

In addition to these main high-enthalpy fields, there are other zones which may also be suitable for electricity generation. These are Afyon-Sandikh (1.2), Ankara-Kizilcahamam (2.1), Ankara-Afyon (2.3), Bahkesir-Smdirgi (4.1), Bahkesir-Gonen (4.3), Canakkale- Kestanbol (8.2), Denizli-Tekkehamam (9.2), Erzurum-Ihca (lO.l), Erzurum-Pasinler (10.3), Eski$ehir (ll.l), Izmir-Dikili-Bergama (13.3), Kuaehir (14.1, 14.2 and 14.3), Ktitahya-Simav (15.1), Manisa-Salihli (16-l), Manisa-Urganh (16.2), and NevSehir-Kazakh (17.1).

Direct thermal energy use from low-enthalpy geothermal sources was initiated 11 yrs ago.21 The fields presently used for heating are Afyon-Sandikh (1.2), Afyon-bmer-Gecek (1. l), Bahkesir-Giinen (4.3), Canakkale-Kestanbol (8.2), Denizli-Tekkehamam (9.2), Eskisehir (ll.l), and Kiitahya-Simav (15.1).

GEOTHERMAL ENERGYIN THE GLOBAL ENERGYBALANCE

In 1986, the total energy consumption in Turkey was recorded to be 149 TJ. The shares of the residential, industrial, transport, agricultural and non-energy use sectors are 44, 29, 18, 4, and 5%, respectively. During the same year 65% of 38 TWh of electricity was generated from thermal conversion plants and the rest from hydraulic resources. Electricity was mostly consumed in industry (63.6%) and in the residential sector (35%). The balance was used in both the transport and agricultural sectors and did not exceed 1.4% of the total.“‘12

The share of geothermal energy production, both for electrical and non-electrical uses, is negligible when compared with these huge quantities. Electricity generated from the Denizli-Ktzildere geothermal power plant during the last 3 yrs is given in Fig. 2. Yearly average generation is about 15 GWh for 7000 h of operation.

When the geothermal energy potential in Turkey is considered (cf. Table l), the utilized fraction is seen to be very small. This is especially important for the country, because almost half of the total commercial energy consumption is supplied by imported fuels. If present trends continue, the energy gap will be three times larger by the year 2000.23

Positive steps should be taken toward exploration of indigenous resources, especially for geothermal energy. Installations of new geothermal power plants are planned by the TEK.9,‘0 Among estimates made by official sources, there are some inconsistincies concerning future depletion of geothermal energy.‘c12,16 Projections provided by the Ministry of Energy and Natural Resources to the year 2010 are given in Table 3.i2 The contributions of other energy sources to total energy production are also illustrated. The figures seem to be optimistic, especially those for renewable energies and geothermal energy. However, even if half of the

Geothermal energy in Turkey 249

1 6-

5-

4-

x 3 0 3-

2-

I-

o-

1964 1985 I966

I 1 Months

Fig. 2. Electricity generation from the Denizli-Klzddere geothermal power plant.

Table 3. Contribution of different energy sources to energy production projected up to 2010 in Turkey.

-r Solid Years Fllel.5 Petroleum

Geothermal Solar

Natural

Gas Hydraulics Thermal Electricity Biomass and Nuclear

Wind

19% 44.6

1990 47.8

1935 40.4 2000 37.0 2010 39.4

9.5

6.8 5.5

4.7

3.1

1.7 11.1 32.9 - - 1.8 19.5 0.05 0.1 23.9 0.05 - 1.4 29.0 0.2 3.5 18.5 0.5 1.0 1.1 32.3 0.4 7.4 14.7 0.5 1.5 0.8 30.0 1.0 5.0 9.4 2.1 9.2

estimates are realized by 2010, petroleum imports would be decreased by 3.2%, while the contribution of geothermal energy would be increased by 3%.

ECONOMIC ASPECTS

The Denizli-Krzrldere plant cost 5.5 x lo9 Turkish Liras in 1984 prices (1 U.S.$ = 300 TL).2”26 Exploration expenditures were approx. 20% of the total installation expenditures of the plant.

For the year 1984, the cost of electricity produced by the plant was forecast to be 3.3 TL/KWhr. The costs of other energy sources for the same year are shown for comparison in Table 4.‘* As is highlighted in Table 4, electricity production from geothermal energy is about 6.5 times less expensive than electricity produced from other energy sources.

Electricity generated from the plant saved 45 X lo9 TL/yr. Moreover, the waste fluid is also used for greenhouse heating and in the textile industry. Together with other uses, the plant made a total contribution of 60 x lo9 TL/yr to the economy of the country.

250 E. TASDEMIRO~LU

Table 4. Cost of energy sources in TL/KWh for 1984.

Electric1 ty Coal (thermal or Kerosene LPG

Electricity

Gas hydraulics)

Fuelrood (geothermal) Lignite Coal

21.5 12.9 9.5 6.9 5.2 3.3 2.6 2.2

Evaluations made with 1986 prices for Afyon show that a geothermal well with a 33% use factor could be amortized in 2 yrs compared with amortization for coal compared with a fuel oi1.16 A similar forecast was made for Izmir-Balcova, 14% use factor could be amortized in 1 and 4yrs when compared with respectively. l6

and in 6 months where a well with fuel-oil and coal,

IMPLICATIONS OF GEOTHERMAL ENERGY EXPLORATION AND UTILIZATION: RECOMMENDATIONS

Potential assessment and exploration studies are conducted in Turkey by MTA, whereas TEK is engaged in commercial electricity generation, in accord with an article recently included into the General Mining Law.*’ However, the efforts devoted by these governmental organizations are not sufficient because of their limited facilities. Problems may be discussed from different perspectives.

Since geothermal energy is a new concept in Turkey, specific regulations related to all aspects of geothermal energy and applications do not exist. Consideration of the legal status of geothermal energy within the existing mining law will lead to confusion since its exploration can not be pursued according to the same exploration rules used for other minerals. Geothermal energy should also be considered separately because of utilization of balneological centers.

Urgent need exists for the passage of a new law. This law must clearly define the nature of geothermal energy sources, including fluid specifications, location, rules for permission of exploration, utilization, management, cooperation among governmental organizations and/or private companies, financial resources necessary for exploration, development of R and D projects, security issues, and environmental conditions.

The machinery, drilling rig and other equipment necessary for geothermal energy exploration may not be provided in time because of financial constraints. This fact led to postponements of scheduled activities in several areas. Shortages of experienced personnel in geothermal work have also been one of the limiting factors for expansion of geothermal exploration and development.

Well drilling does not require advanced technology but rather large capital investments. There is a cooperative program with Italy which is one of the most experienced countries in the world in the geothermal area. Carefully planned technology transfer from Italy will help the development of our technological capacity. On the other hand, some parts of the machinery and drilling equipment can possibly be produced from locally available materials. For this purpose, production strategies should carefully be examined.

In the Kizildere geothermal power plant, encasing occurred due to silica scaling in wellheads and pipes. This fact caused problems on the disposal side of the network, downstream of the heat-transfer region. When disposal facilities are obstructed, scales have been removed by reaming in periodic drillings every 6 months. CO2 injection into the wells was also planned in order to prevent down-hole scaling. In Afyon and Izmir-Balsova, the down-hole heat exchangers were placed in the wells to avoid the effects of scaling and corrosion.

In the Krzrldere plant, the waste fluid contains a large amount of borax, the disposal of which has environmental implications. At present, there are three different solutions for considera- tion for this problem. These are reinjection, purification and drainage of the wastewater into the Aegean Sea; reinjection, if it can be achieved, will be the best solution.

Geothermal energy in Turkey 2.51

REFERENCES

1. A. K. Tezcan, “Gravity and Resistivity of Results of Denizli-Saraykoy Geothermal Energy Research,” (in Turkish), MTA Report No. 3896, Ankara, Turkey (1967).

2. H. Uysalh, “Geological Studies and Geothermal Energy Possibilities in the Tekke-Krzrldere Hot Water Fields,” (in Turkish), MTA Report No. 3874, Ankara, Turkey (1967).

3. E. Samilgil, “Geological and Hydrological Studies Performed for Geothermal Energy Surveys in the Canakkale-Tuzla and Kestanbol Fields,” (in Turkish), MTA Report No. 4274, Ankara, Turkey (1970).

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5. A. Ekingen, “Gradient Studies in iihe Denizli-Derekoy Field,” (in Turkish), MTA Report No. 4788, Ankara, Turkey (1970).

6. H. Uysalh and B. Keskin, “KD-1, KD-II, TH-L, KD-l/A, KD-III, IV, VI, IX, XII, XIII, VIII, and XIV Deep Wells Completion Report in the Denizli-Saraykiiy Field,” (in Turkish), MTA Report No. 4441, Ankara, Turkey (1971).

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of N. Turkish Energy Congress, Vol. 1, pp.

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Geothermics, Special Issue 2, 553

21. S. Simaek, “Present Status and Future Development of the Denizli-Kmldere Geothermal Field and Geothermal Update Report of Turkey,” Volume, p. 203, Hawai, HI (1985).

Proc. of Int. Symposium on Geothermal Energy, Int.

22. S. Simsek, “Aydm-Germencik-Omerbeyli Geothermal Field of Turkey,” Proc. of UN Seminar on Utilization of Geothermal Energy for Electric Power Production and Space Heating, Ep/Sem.9/R.37, Florence, Italy (1984).

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24. N. Btike and C. Karakaya, “Kizrldere Geothermal Field and Denizli Geothermal Power Plant,” Turkish Electricity Board, unpublished.

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27. Turkish Mining Law, revised version approved by No. 3213 (4 June 1985).