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The Current Status of Geothermal Energy Use in Turkey

Kamil B. VARINCA

Yildiz Technical University Environmental Engineering Department Davutpasa Campus, 34220, Istanbul, Türkiye

kvarinca@yidliz.edu.tr

ABSTRACT

Although Turkey has a great geothermal potential (Turkey is the seventh richest country in the world and the second richest country in Europe in geothermal energy potential), it uses only

about 4% of this potential efficiently and electricity generation from geothermal energy is rather low.

Geothermal energy has the potential to play an important role in the future energy supply of

Turkey. In spite of the complex legal issues related to the development of Turkey's geothermal resources, their use is expected to increase in the future, particularly for electricity generation and

for greenhouse heating. Present applications have shown that geothermal energy is clean and much cheaper compared to the other fossil fuels and other renewable energy sources for Turkey. Therefore, it is a promising alternative and development studies and investments in this sector

should be supported. This paper presents the status of energy needs and, potential, utilization and the importance of

geothermal energy in Turkey. Keywords: Geothermal energy, Turkey.

INTRODUCTION

Geothermal energy, as natural steam and hot water, has been exploited for decades to generate

electricity, and both in space heating and industrial processes. Geothermal energy (GE) is the heat (thermal) stored in the earth (geo). It is the thermal energy contained in rocks and fluids (that fill the fractures and pores within the rock) in the earth’s crust.

Turkey is located in the Mediterranean sector of Alpine–Himalayan Tectonic Belt and has a place among the first seven countries in the world in the abundance of geothermal resources.

Turkey presently has one operating geothermal power plant, located near Denizli City in Western Anatolia with an installed capacity of 20.4 MW and an electrical energy production of 89,597 MW h in 2001 [1].

Turkey’s total electricity production and installed capacity were 191.6 GW h and 41.7 GW, respectively, in 2007. The distribution of the produced electricity energy according to primary

energy sources was as follows: natural gas 49.6%, coal 27.9%, hydropower 18.7%, oil 3.4%, geothermal 0.08% (156 GWh) and wind 0.2% and total geothermal installed capacity is 30 MW (%0,07) [2].

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1.1 A brief historical development of geothermal energy

As for a brief history of geothermal energy development in Turkey, before the 1960s, geothermal resources were only used spontaneously in bathing and medical treatment in Turkey.

The General Directorate of Mineral Research and Exploitation (called MTA in Turkey) has carried out geothermal energy explorations in Turkey. Inventorial works and chemical analyses of hot

springs and mineral waters started in 1962. Since then, the following evolution in time of geothermal energy development has occurred [1]:

The first geothermal well was drilled in the Izmir-Balcova geothermal field in 1963.

The Denizli–Kizildere geothermal field was discovered in 1963.

The first space heating application by geothermal energy was in a hotel in Gonen-

Balikesir in 1964.

The first geological, geochemical, and geophysical studies were carried out with the

support of the United Nations Development Program (UNDP) in the Denizli-Kizildere geothermal field in 1966.

The investigations of geothermal energy in the country gained speed in the 1970s.

The first geothermal well was drilled in the Izmir-Balcova geothermal field in 1963.

The Denizli–Kizildere geothermal field was discovered in 1963.

The first space heating application by geothermal energy was in a hotel in Gonen-

Balikesir in 1964.

The first geological, geochemical, and geophysical studies were carried out with the

support of the United Nations Development Program (UNDP) in the Denizli-Kizildere geothermal field in 1966.

The investigations of geothermal energy in the country gained speed in the 1970s.

The first experimental study on a geothermal (ground-source) heat pump with a

horizontal loop configuration at the university level was carried out at the Mechanical Engineering Department, Middle East Technical University, Ankara, in 1986, while that

with a vertical loop configuration was performed in the Solar Energy Institute, Ege University, Izmir, in 2000.

Geothermal district heating applications started in 1987 in Turkey with the heating of 600

residences in Balikesir-Gonen.

After 1990, geothermal direct-use applications increased as steeply as 185% from 1990 to

1995.

The first residential geothermal heat pump system (or ground-source heat pump system)

was installed in a villa with a floor area of 276 m2 in Istanbul in 1998.

1.2 Geothermal energy utilization in Turkey

In Turkey, around 600 geothermal prospects and 170 geothermal fields with a temperature range of 40–242 °C have been discovered. The total proven geothermal electricity generation

capacity is 200 MWe, while the direct use capacity is 2046 MWt. This proven potential increases by 5% annually with new exploration and drilling activities. The geothermal electricity generation

capacity potential of Turkey is estimated at 2000 MW (16 TW h/year) and a generation capacity of 550 MW that utilizes geothermal sources is expected by the year 2013. The estimated geothermal power and direct use potential are reported as 4500 MWe and 31,500 MWt, respectively. It is

projected that, by the years 2010 and 2020, the total installed capacity will increase to 3500 MW (500,000 residence equivalent, which is about 30% of the total residences in the country) and 8300

MW (1,250,000 residence equivalent) for space heating, respectively. The potential for geothermal development in Turkey is generally considered large in terms of moderate and low temperature resources (<150 °C). Out of Turkey’s total geothermal potential, around 94% is appropriate for

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thermal use (temperature less than 150 °C) and the remainder for electricity production (temperature more than 150 °C) [1, 2].

Most of the development in the direct use has been in district heating, which now serves

103,000 residences (827MWt and 7712.7 TJ/yr), and in individual space heating (74 MWt and 816.8 TJ/yr). A total of 800,000 m2 of greenhouses are heated by geothermal fluids (192 MWt and 3633

TJ/yr). Geothermal heated pools used for bathing and swimming account for a capacity of 402MWt and utilize 12677.4 TJ/yr. About 120,000 tonnes of liquid carbon dioxide and dry ice are produced annually at the Kizildere power plant. By the year 2010, Turkey aims at having 500 MWe dedicated

to electricity generation and 3500MWt for space heating. Heat pumps are not being used at present, because of the high cost of electricity [3, 4].

1.3 Electricity generation

About 95% of the 170 geothermal fields in Turkey are low-medium enthalpy fields, which are

suitable for direct use applications. The list of high-temperature geothermal fields suitable for conventional electricity generation in Turkey is shown in Table 1; the locations of the geothermal

fields are illustrated in Fig. 1, while the four fields of highest temperature are summarized below.

Table 1. Geothermal fields suitable for conventional electricity generation in Turkey [1, 2]. Geothermal field Temperature Geothermal field Temperature

Denizli–Kizildere 200–242 °C Izmir–Seferihisar 153 °C

Aydin–Germencik 232 °C Manisa–Salihli–Caferbey 150 °C Manisa–Salihli–Gobekli 182 °C Aydin–Yilmazkoy 142 °C

Canakkale–Tuzla 174 °C Izmir–Balcova 136 °C Aydin–Salavatli 171 °C Izmir–Dikili 130 °C

Kutahya–Simav 162 °C

Fig. 1. Location of major geothermal fields in Turkey. In the Aegean Coastal Belt: (A1) Seferihisar, (A2) Çesme, (A3) Balçova, (A4) Aliağa, (A5) Dikili-Bademli, (A6) Edremit, (A7)Tuzla, and (A8)

Kestanbol; in the Western Anatolian grabens: (B1) Germencik, (B2) Aydın, (B3) Salavatlı-Sultanhisar, (B4) Kızıldere, and (B5) Denizli; (B6) Salihli-Kurs ̧ unlu, Caferebeyli and Sart, (B7)

Turgutlu-Urganlı, (B8) Alaşehir-Kavaklıdere, (B9) Dikili-Kaynarca, (B10) and Bergamaand (B11) Simav; inCentral Anatolia: (C1) Afyon, (C2) Cappadocia, (C3) Kırşehir, (C4) Kozaklı, and (C5) Kızılcahamam; in Eastern Anatolia: (D1)Nemrut Caldera, (D2) Erciş-Zilan, and (D3) Diyadin; in

the North Anatolian Fault Zone: (E1) Erzincan, (E2) Çerkes ̧ , (E3) Bolu, (E4) Düzce, (E5) Bursa and (E6) Gönen. NAFZ: North Anatolian Fault Zone; EAFZ: East Anatolian Fault Zone.

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Geothermal district-heating systems: (1) Gönen-Balıkesir, (2) Simav-Kütahya, (3) Kırşehir, (4) Kızılcahamam-Ankara, (5) Balçova-İzmir, (6) Afyon, (7) Kozaklı-Nevşehir, (8) Sandıklı-Afyon, (9)

Diyadin-Ağrı, (10) Salihli-Manisa, (11) Dikili-İzmir, 12 Sarayköy-Denizli, (13) Edremit-

Çanakkale, (14) Bigadiç -Balıkesir, (15) Bergama-İzmir, (16) Kuzuluk-Sakarya, (17) Armutlu-Yalova, (18) Güre-Balıkesir, (19) Sorgun-Yozgat and (20) Yerköy-Yozgat. Geothermal

greenhouses: (1) Dikili-İzmir, (2) Salihli-Manisa, (3) Turgutlu-Manisa, (4) Balçova-İzmir, (5) Kızıldere-Denizli, (6) Gümüşköy-Aydın, (7) Diyadin-Ağrı, (8) Karacaali-Urfa, (9) Sındırgı-

Balıkesir and (10) Simav-Kütahya. Geothermal power plants: (1) Kızıldere-Denizli, (2 and 3) Dora-

1 and Dora-2, Salavatlı-Aydın, (4) Gürmat, Germencik-Aydın (5) Bereket, Kızıldere-Denizli and (6) Tuzla-Çanakkale [5].

The Denizli–Kizildere geothermal field

Turkey’s first commercial geothermal power plant is the Denizli–Kizildere geothermal power

plant (DKGPP), located near Denizli City ((31 km away from the city’s center) in Western Anatolia. It was discovered by the MTA in 1968 and a power plant was installed there in 1984 with

a capacity of 20.4 MW. The total capacity of the field is estimated to be 200 MWe [1, 2]. Studies of the geology, geophysics (gravity, resistivity, seismicity) and geochemistry and

gradient drilling were carried out between 1965 and 1968. To date, a total of 20 deep wells varying

in depth from 370 to 1241 m have been drilled, while the encountered temperatures were in the range of 170–212 °C [1].

The most significant characteristic of the field is the high amount of non-condensable gases (2.5% in the reservoir, 5% by volume of steam, 10–21% by weight of steam and average 13% by weight of steam at the turbine inlet), with a CO2 content of 96–99%, H2S content of 100–200 ppm

and NH3 content of 72 ppm. A liquid CO2 and dry ice production process with a capacity of 40,000 tons/year was built adjacent to the field in 1986. The capacity of the process was increased to

120,000 tons/year in 1999. Besides electricity and dry ice production, the resources of the field have also been used for greenhouse heating and space heating of offices and staff houses of the plant [1].

The electricity generation of the Denizli–Kizildere geothermal power plant between 1984 and

2001 is illustrated in Fig. 2. As can be seen in this figure, the plant produced on average an electrical energy of 84,920 MW h in the period between 1984 and 2002, representing an average

electric power of 10.45 MWe in the same period.

Fig. 2. Electricity generation of the Denizli–Kizildere power plant between 1984 and 2001 [1].

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The Aydin-Germencik geothermal field

This area is placed on 100 kmwest of Kızıldere in western Anatolia. Aydin-Germencik geothermal field, which is the second economical geothermal field for generating electricity, was

discovered by the MTA. This field, where geothermal studies started in 1967, is located in the west of Buyuk Menderes Graben about 40 km from the Aegean Sea. After geological, geophysical and

geochemical studies, 10 exploration wells with depths between 285-2398 m have been drilled. The temperatures of the first and second reservoirs are found to be 203-217 °C and 216-232 °C. The average flow rate is 300 tone/h and steam ratio changes from13 to 20%. The collected data indicate

that the field has important geothermal potential. Disposed hot water can be used in electricity generation, district heating, and industry and in touristic and balneological centers. A binary cycle

power plant with an installed capacity of 25 MWe will be constructed at Aydın/Germencik in 2004. The field capacity is estimated to be 100 MWe [1, 3, 6].

The Canakkale-Tuzla geothermal field

The third field with power generation potential is the Canakkale-Tuzla field in northwest

Anatolia. The first well was drilled in 1982, and the temperature encountered was 174 °C in a reservoir at a depth of 333–553 m in volcanic rocks. A second well was drilled to 1020 m. Temperatures up to 174 °C were recorded, but the permeability was low. Another two shallow wells

with depths of 81 and 128 m also produced fluid at 146 and 165 °C [1].

The Aydin-Salavatli geothermal field

This field is placed close to the central part of the Buyuk Menderes graben and at the same distance from the Denizli–Kizildere and Aydin-Germencik geothermal fields. Ten exploration wells

with depths of 1510 and 962 m were drilled in 1987 and 1988, and their reservoir temperatures were 162 and 171 °C, respectively. It was planned to build a 5 MWe binary or Kalina cycle plant in

the field, but this has not been realized yet [1, 6].

The Izmir-Seferihisar geothermal field

Between 1986–1997 period, 15 wells were drilled and the reservoir temperature was measured as 153 °C. The 9.7 MWt heat is discharged from five wells by downhole heat exchanger

system. It is estimated that 3600 m2 greenhouse can be heated with this energy [6].

CONCLUSION

Geothermal energy provides a clean, renewable energy source that could dramatically improve our environment, economy and energy security. Geothermal energy generates far less

(almost none) air emissions than fossil fuels and decreases the reliance on imported energy. Today, in most ways, geothermal energy has come of age; the technology has improved, the economics has become more appealing, and substantial progress has been achieved in reducing environmental

impacts. Turkey is an energy importing country. In order to be less dependent on other countries,

Turkey needs to use its sustainable sources. From this point of view, geothermal energy is a very attractive choice, since it is economical, sustainable, environmental friendly and a familiar energy source in Turkey. Furthermore, Turkey has several advantages for the use of geothermal energy in

terms of its location and geological background.

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REFERENCES

[1] Hepbasli, A., & Ozgener, L. (2004). Development of geothermal energy utilization in Turkey: a review. Renewable and Sustainable Energy Reviews (8), 433-460.

[2] Erdogdu, E. (2009). A snapshot of geothermal energy potential and utilization in Turkey. Renewable and Sustainable Energy Reviews (13), 2535-2543.

[3] Akpınar, A., Kömürcü, M. İ., Önsoy, H., & Kaygusuz, K. (2008). Status of geothermal energy amongst Turkey’s energy sources. Renewable and Sustainable Energy Reviews (12), 1148-1161.

[4] Akpınar, A., Kömürcü, M. İ., Kankal, M., Özölçer, İ. H., & Kaygusuz, K . (2008). Energy situation and renewables in Turkey and environmental effects of energy use. Renewable and

Sustainable Energy Reviews (12), 2013-2039. [5] Serpen, U., Aksoy, N., Öngür, T., & Korkmaz, E. D. (2009). Geothermal energy in Turkey:

2008 update. Geothermics (38), 227-237.

[6] Kaygusuz, K., & Kaygusuz, A. (2004). Geothermal energy in Turkey: the sustainable future. Renewable and Sustainable Energy Reviews (8), 545-563.

BIOGRAPHY

Kamil B. VARINCA (Ms.C.) was born Bayburt (Turkey) in 1981. He works as a research assistant at Yıldız Technical University Environmental Engineering Department. Varınca received his BSc in

Environmental Engineering in 2002 from İstanbul University, İstanbul, Turkey, and his MSc in Environmental Engineering in 2006 from Yıldız Technical University, İstanbul, Turkey. He is still

PhD student on Hazardous Waste Management at Yıldız Technical University Environmental Engineering Department. His main subject areas are Solid and Hazardous Waste Management and Renewable Energy

Mr. Varınca is a member of Chamber of Environmental Engineers (CEE) and Turkish National Committee on Solid Wastes (TNCSW).

He may be contacted at kvarinca@yildiz.edu.tr or kvarinca@gmail.com.