renewable energy potential and utilization in turkey

Renewable energy potential and utilization in Turkey

Kamil Kaygusuz a,*, Ahmet Sar b

a Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkeyb Department of Chemistry, Gaziosmanpasa University, 60100 Tokat, Turkey

Abstract

Renewable energy sources have been important for humans since the beginning of civilisation. Forcenturies, and in many ways, biomass has been used for heating, and cooking. Many centuries ago,mankind was already utilizing the clearly visible power of water for mechanical drive purposes, as was alsothe case with wind. Today, water mills are still used in our villages, although their numbers are going todiminish. On the other hand, Turkey is an energy importing country with more than half of the energyrequirement being supplied by imports, and air pollution is becoming a great environmental concern in thecountry. In this regard, renewable energy resources appear to be one of the most ecient and eectivesolutions for sustainable energy development and environmental pollution prevention in Turkey. Turkeysgeographical location has several advantages for extensive use of most of the renewable energy sources.Because of this and the fact that it has limited fossil fuel resources, a gradual shift from fossil fuels torenewables seems to be serious and the sole alternative for Turkey. This article presents a review of recentstudies on the renewable energy sources, their potential and present use in Turkey. 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Renewable energy; Sustainable energy development; Solar energy; Biomass

1. Introduction

Energy is essential to economic and social development and improved quality of life in Turkey,as in other countries. Much of the worlds energy, however, is currently produced and consumedin ways that could not be sustained if technology were to remain constant and if overall quantitieswere to increase substantially. The need to control atmospheric emissions of greenhouse and othergases and substances will increasingly need to be focussed on eciency in energy production,

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*Corresponding author. Fax: +90-462-325-3195.

E-mail address: [email protected] (K. Kaygusuz).

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transmission, distribution and consumption in the country. On the other hand, electricity sup-ply infrastructures in Turkey, as in many developing countries, are being rapidly expanded,as policymakers and investors around the world increasingly recognize electricitys pivotal role inimproving living standards and sustaining economic growth. On the contrary, in the comingdecades, global environmental issues could signicantly aect patterns of energy use around theworld, as in Turkey. Any future eorts to limit carbon emissions are likely to alter the compo-sition of total energy related carbon emissions by energy source in the country [1].Energy is considered a prime agent in the generation of wealth and also a signicant factor in

economic development. The importance of energy in economic development has been recognizedalmost universally. The historical data attest to a strong relationship between the availability ofenergy and economic activity. During the past two decades, the risk and reality of environmentaldegradation have become more apparent. Growing evidence of environmental problems is due toa combination of several factors, since the environmental impact of human activities has growndramatically because of the sheer increase of world population, consumption, industrial activityetc. Achieving solutions to the environmental problems we face today requires long term potentialactions for sustainable development. In this regard, renewable energy resources appear to be oneof the most ecient and eective solutions. That is why there is an intimate connection betweenrenewable energy and sustainable development [2].The Kyoto Protocol to the United Nations Framework Convention on Climate Change, agreed

to in December 1997, marks an important turning point in eorts to promote the use of renewableenergy worldwide. Since the original Framework Convention was signed at the Earth Summit inRio de Janeiro in 1992, evidences of climate change have spurred many countries to increase theirsupport of renewable energy. Even more ambitious eorts to promote renewables can be expectedas a result of the Kyoto pact, which includes legally binding emissions limits for industrialcountries, and for the rst time, specially identies promotion of renewable energy as a keystrategy for reducing greenhouse gas emissions [3].Sunlight can be used directly for heating and lighting residential and commercial buildings. The

heat of the sun can be harnessed for hot water heating, solar cooling and other commercial andindustrial uses. The suns heat can also be used to generate electricity, using a technology calledsolar thermal electric power. Sunlight can also be converted directly to electricity using photo-voltaic (PV) solar cells. Many other forms of renewable energy are indirectly powered by the sun.For example, the suns heat drives the winds which produce energy that is captured with windturbines. Winds, in turn, cause ocean waves, producing energy that can be converted to electricity.Sunlight also causes plants to grow, and the energy stored in those plants is known as biomassenergy (wood, straw, dung and other plant wastes). Biomass can be converted to liquid or gaseousfuels or burned to produce electricity [4].Turkeys geographic location has several advantages for extensive use of most of the renewable

energy sources. It is on the humid and warm climatic belt, which includes most of Europe, thenear east and western Asia. A typical Mediterranean climate is predominant at most of its coastalareas, whereas the climate at the interior part between the mountains that are a part of theAlpineHimalayan mountain belt is dry with typical steppe vegetation. This is mainly because thecountry is surrounded by seas at three sides: the Black sea at the north, the Marmara sea andAegean sea to the west and the Mediterranean sea to the south. The average rainfall nationwide isabout 650 mm, but this average masks large variations, from about 250 mm in the central and

460 K. Kaygusuz, A. Sar / Energy Conversion and Management 44 (2003) 459478

Southeastern plateaus to as high as 2500 mm in the Northeastern coastal plains and mountains.In the western and southern coastal zones, a subtropical Mediterranean climate predominates,with short, mild and wet winters and long, hot and dry summers. Arid and semi-arid continentalclimates prevail in the central regions, where winter conditions are often extremely harsh,with frequent and heavy snowfall in the higher parts of the Anatolian Plain. On the Black Seacoast, winters are very wet and summers mild and humid. The average annual temperaturevaries between 18 and 20 C on the south coast, drops to 1416 C on the west coast and inthe central parts uctuates between 4 and 18 C. Local micro-climates can vary widely from theregional averages because of the highly variable terrain and exposure to hot and cold winds [5].Although Turkey has almost all kinds of energy resources, it is an energy importing country,

since these resources are limited. More than half of the primary energy consumption in thecountry is met by imports, and the share of imports continues to increase each year. Therefore, itseems that if the country wants to supply its demand by domestic resources (such as lignite, hardcoal, oil and natural gas), the transition to renewable energy resources must be realised in areasonable time period [6]. On the other hand, the total renewable energy production and con-sumption of Turkey are equal to each other, varying between 9.6 and 10.8 million tons of oilequivalent (toe) each for the 19921999 period (Table 1). Their share in total energy productionvaries on average between 37% and 43%, while in total consumption, it varies between 15% and22% for the same period. Among the production of renewables, biomass that includes wood anddung, is the highest in 1992, reaching 7.2 million toe. The second highest is hydroelectric pro-duction, which reached 3.5 million toe in 1998. The production of geothermal and solar energy isnegligible compared with biomass and hydroelectric power, varying from 122 to 388 thousandtoe between 1992 and 1999 (see Table 1). On the other hand, Turkeys rst wind farm wascommissioned in 1998 and has a capacity of 1.5 MW. Capacity is likely to grow rapidly, as plans

Table 1

Primary energy consumption of Turkey between 19921999 (ktoe)

1992 1993 1994 1995 1996 1997 1998 1999

Non-Renewable

Hard coal 6803 6671 6428 6690 9115 8495 8160 11 286

Lignite 10 743 9918 10 331 10 605 11 187 12 280 12 414 12 984

Oil 24 865 28 412 27 142 29 324 30 939 30 515 32 083 32 916

Natural gas 4197 4630 4921 6313 7384 9165 10 635 12 902

Total fossil 46 608 49 631 48 822 52 932 58 625 60 455 63 292 70 088

Renewable

Hydropower 2285 2920 2630 3057 3481 3424 3520 3240

Geothermal 90 97 115 138 162 179 256 274

Solar 32 38 45 52 80 80 98 114

Wood 5421 5451 5482 5512 5512 5512 5512 5512

Waste and dung 1788 1697 1627 1556 1533 1512 1492 1510

Total renewable 9616 10 203 9899 10 315 10 768 10 707 10 878 10 650

Total consumption 56 224 59 834 58 721 63 247 69 393 71 162 74 170 80 738

Total production 26 408 26 021 26 059 26 255 26 926 27 687 28 784 27 065

Source: Ref. [7].

K. Kaygusuz, A. Sar / Energy Conversion and Management 44 (2003) 459478 461

have been submitted for just under a further 600 MW of independent facilities, of which 57 MW isat an advanced stage in negotiations. The majority of the proposed projects are located in C esme(_IIzmir) and Canakkale [6].

2. Present energy use in Turkey

The energy demand of Turkey will be doubled between the years 20002010 and will be vefoldbetween 20002025. This rapid increase in demand is due to the high economic development rateof Turkey. The estimated amount of investments for the production facilities by the year 2010 isaround 45 billion dollars. Transmission and distribution facilities will require an additional 10billion dollar investment in the same period. The government has undertaken measures to attractnew local and foreign private sector investments and also to transfer operational rights of existingunits to the private sector for their renewal and ecient operation [6,7].Turkey is an energy importing country. More than half of the energy requirement has been

supplied by imports. Oil has the biggest share in total primary energy consumption. Because ofthe diversication eorts of energy sources, the use of natural gas, that was newly introduced intothe Turkish economy, has been growing rapidly. Turkey has large reserves of coal, particularly oflignite. The proven lignite reserves are 8.0 billion tons. The estimated total possible reserves are30 billion tons. A majority of these lignite reverses, mostly situated in Asn-Elbistan, Soma andTuncbilek, are characterized with high ash contents in the range of 1442%, high moisturecontents ranging from 15% to 50% and volatile matter contents of 1638% [6]. On the otherhand, important developments have been recorded in primary energy and electricity consump-tion during the last 40 years. In this period, primary energy consumption has increased byan average of 5.0% and electricity consumption by 10%, annually. Despite high growth rates,primary energy and electricity consumption are quite below the levels of OECD countries[8,9].In 1999, primary energy production and consumption has reached 27 and 80.7 million tons of

oil equivalent (mtoe), respectively (Table 1). The most signicant developments in production areobserved in hydropower, geothermal, solar energy and oil production. Oil production reached 4.5million tons in 1991, the highest level in its history. Thus, the share of indigenous oil in the totaloil supply rose to 20%. However, this development could not be maintained in the following years,and production of oil has entered a regression period. On the other hand, as of the end of 1999,the installed capacity and generation capacity of power plants reached 19 952 MW and 116 447GWh, respectively. As of 1999, the electricity demand, amounting to 88 billion kWh, was metcontinuously with a high reserve margin. However, it is crucial to ensure the continuity of in-vestments in order to meet the electricity demand continuously and safely in coming years, whichis increasing rapidly.The ndings of the Ministry of Energy and Natural Resources suggest that the primary energy

demand will be equivalent to 91 030 kilotonnes of oil equivalent (ktoe) in the year 2000, and314,353 ktoe in 2020 in Turkey. In line with this trend, in 2023, marking the centennial of thecountry, the primary energy consumption will reach 367 780 and 407 106 ktoe two years later in2025. According to the Ministrys production forecasts, domestic production of primary energy


will be 31 091 ktoe in 2000 and 79 399 ktoe by 2020. The projections foresee domestic generationto exceed 91 408 ktoe in 2023 and 95 946 ktoe in 2025. Table 2 gives the ndings related to primaryenergy resources and their domestic production planning.

3. Water potential in Turkey

The annual average precipitation in Turkey is estimated at 643 mm, corresponding to a volumeof 500 km3. The average runo coecient is 0.37, and the annual runo is 186 km3 (2400 m3/ha).Subtracting from this gure the estimated water rights of neighbouring countries, minimumstream-ow requirements for pollution control, aquatic life and navigation, and topographic andgeologic constraints, the annual consumable water potential of 12 km3 should be added to this,bringing the total annual consumable potential to 107 km3 [10].Precipitation diers considerably, both from year to year and among the river basins. The

annual depth of precipitation is as high as 250 cm in the Eastern Black Sea region and as low as 30cm in some parts of Central Anatolia. Most of the countrys water potential lies in the southeast(28%) and the Black Sea region (8%). Turkeys water resources can be considered in 26 drainagebasins. Table 3 shows the water and energy potential of selected river basins in Turkey. The mostimportant rivers are the Frat River (Euphrates) and Dicle River (Tigris), both of which aretransboundary rivers originating in Turkey and discharging into the Persian (Arabian) Gulf.The Meric, Coruh, Aras, Arapcay and Asi Rivers are the other transboundary rivers. Some

Table 2

Primary energy production and consumption (in parenthesis) targets of Turkey (ktoe)

Energy sources 2000 2005 2010 2015 2020 2025

Hard coal and lignite 17 202 21 259 28 522 31 820 39 385 45 944

(20 256) (30 474) (50 311) (83 258) (129 106) (296 997)

Oil and natural gas 3408 2127 1735 1516 1604 1455

(59 250) (73 256) (92 637) (112 993) (136 365) (179 765)

Central heating 253 495 884 1336 2018 2748

(253) (495) (884) (1336) (2018) (2748)

Hydropower 3763 5845 7520 8873 9454 10 445

(3763) (5845) (7520) (8873) (9454) (10 445)

Wood and waste 6963 6760 6446 6029 5681 5393

(6963) (6760) (6446) (6029) (5681) (5393)

Geothermal 432 1380 3760 4860 4860 5400

(432) (1380) (3760) (4860) (4860) (5400)

Nuclear 0.0 0.0 3657 9143 18 286 29 200

(0.0) (0.0) (3657) (9143) (18 286) (29 200)

Solar 204 459 907 1508 2294 3248

(204) (459) (907) (1508) (2294) (3248)

Wind 55 250 620 980 1440 2134

(55) (250) (620) (980) (1440) (2134)

Source: Ref. [6,7].


22% of the boundaries between Turkey and the neighbouring countries are along internationalrivers [10].

3.1. Hydroelectricity

Hydroelectricity is well established as one of the principal energy producing technologiesaround the world, providing some 20% of the worlds electricity. In the developing countries, theproportion rises to around 40%. The capacity of large hydroelectric schemes can be several timesthat of a conventional power station. They are highly ecient, reliable and long lasting. They arealso very controllable and add an element of storage into an electricity supply system, therebyallowing compensation for the varying intensity of other renewable energy sources and forvariations in electricity demand. However, the dams and their large lake forms also have majorenvironmental and social impacts [1116].There are 436 sites available for hydroelectric plant construction, distributed on 26 main river

zones. Table 3 gives the water and hydroelectric energy potential of selected river basins inTurkey. The total gross potential and total energy production capacity of these sites are nearly 50GW and 112 TWh/y, respectively. As an average, 30% of the total gross potential may be eco-nomically exploitable. At present, only about 18% of the total hydroelectric power potential isexploited. The national development plan aims to harvest all of the hydroelectric potential by2010. The contribution of small hydroelectric plants to the total electricity generation is estimatedto be 510% [13,16].

Table 3

Water and energy potential of selected river basins in Turkey

Name of

Basin

Land area

(km2)

Average rain-

fall (mm/y)

Number of

dam

Stored water

(hm3)

Installed

capacity

(MW)

Average

generation

(GWh)

Susurluk 22 399 711.6 25 3509.3 537.0 1697

Gediz 18 000 603.0 14 3369.4 250.0 425

B. Menderes 24 976 664.3 19 2722.1 214.5 848

B. Akdeniz 20 953 875.8 24 1836.6 674.7 2495

Antalya 19 577 1000.4 15 2885.3 1251.6 4411

Sakarya 58 160 524.7 45 6920.3 1062.5 2362

B. Karadeniz 29 598 811.0 24 2518.8 592.7 2110

Yesilrmak 36 114 496.5 45 6301.8 1657.6 6468Kzlrmak 78 180 446.1 82 21 260.0 2007.0 6512

D. Akdeniz 22 048 745.0 11 9121.5 1495.9 5176

Seyhan 20 450 624.0 18 6124.5 1885.6 7117

Ceyhan 21 982 731.6 25 7719.5 1408.7 4634

Frat 127 304 540.1 83 112 791.5 9844.8 38 939

D. Karadeniz 24 077 1198.2 43 1522.5 3323.1 10 927

Coruh 19 872 629.4 20 7544.4 3227.4 10 614Aras 27 548 432.4 20 4084.8 585.2 2291

Dicle 57 614 807.2 36 30 295.0 5081.9 16 876

Total Turkey 77 9452 642.6 702 240 763.6 35 309.2 124 568

Source: Ref. [14].


3.2. Southeastern Anatolia project (GAP)

The Southeastern Anatolia Project (GAP) is one of the largest power generating, irrigation anddevelopment projects of its kind in the world, covering 3 million ha of agricultural land. This isover 10% of the cultivable land in Turkey. The land to be irrigated is more than half of thepresently irrigated area in Turkey. GAP is an integrated development project. It is expected toaect the entire structure of the region in its economic, social and cultural dimensions through aprocess of transformations to be triggered by agricultural modernization. It is envisaged as themeans of bridging the gap between the southeastern region and the more advanced areas ofTurkey and of increasing the welfare of the region. The GAP project on the Euphrates and TigrisRivers encompasses 22 dams and 19 hydroelectric power plants. Once completed, 27 billion kWhof electricity will be generated and 1.7 million ha irrigated [12,14].The Atatuurk Dam has been important in the completion of the Lower Euphrates Project and

even the entire GAP project, for it is the water source of the four projects aimed at irrigation of852 781 ha. The total area to be irrigated from the Atatuurk Dam will reach approximately1 000 000 ha. The Atatuurk Dam, which is the sixth largest volume dam (48.7 billion m3) in theworld, is installed in the Urfa province by the DSI. The type of dam is rock packed, 169 m highfrom the river bed and 1664 m long crest. The body packed volume of the dam is 84.5 million m3.The Atatuurk Dam has eight units with 300 MW installed capacity of each unit, and the meanvalue of electrical energy production is 8.5 billion kWh/y.The energy potential of the Tigris and Euphrates is estimated as 12 000 and 35 000 GWh res-

pectively. These two rivers constitute 10% and 30% of the total hydroelectric energy potential. TheGAP region will be an important electric power producer with 1000 MW installed capacity fromthe Karakaya Dam, 2400 MW installed capacity from the Atatuurk Dam and 1360 MW installedcapacity from the Keban Dam. Table 4 shows the GAP and Turkey comparative gures forhydropower. There are also thermal power plants, fuelled by coal or lignite in the region.Moreover, there are the Caggcagg III, the small hydroplant power with 14.5 MW installed capacity,and the Kralkz on the river Tigris with 90 MW capacity. A Tigris hydropower plant (HPP) andthe 185.6 MW Batman HPP are under construction. When these power plants are completed,the installed capacity in the region will reach 5960 MW with total annual energy production of

Table 4

The GAP and Turkey comparative gures for hydropower

Years GAP hydraulic

(GWh)

National production GAP/Turkey

Thermal

(GWh)

Hydraulic

(GWh)

Total (GWh) Hydraulic (%) Total (%)

1995 16 114 52 548 31 973 84 521 50 19

1996 19 314 54 448 40 423 94 871 48 20

1997 19 385 63 299 39 764 103 063 48.7 18.8

1998 20 053 68 677 42 224 110 901 47.5 18

1999 14 781 81 800 34 629 116 429 42.7 12.7

2000a 6992 43 531 17 632 61 163 39.7 11.4

Source: Ref. [16].a For rst 6 months of the year.


21 900 GWh. The GAP region, with this capacity, will supply 25% of Turkeys electricity and 85%of its hydroelectric energy.The Sanlurfa Irrigation Tunnel system, the largest of its kind, numerous irrigation networks,

and canal systems constitute the physical groundwork in water resources. The tunnel systemcontains two parallel tunnels with each tunnel 26.4 km long. The inner diameter of each tunnel is7.62 m, and the irrigated area by the two tunnels is 476 000 ha. The irrigation aspect of the waterresource development eorts will help in removing an obstacle to development of the region. Inother words, irrigation is crucially important for the regions development. Naturally, the changescreated by irrigation will aect both the people of the region and the countrys welfare positively[12,14].

4. Biomass

Biomass energy includes fuelwood, agricultural residues, animal wastes, charcoal and otherfuels derived from biological sources. It is used by approximately half of the worlds population ascooking and/or heating fuel, and it currently accounts for about 14% of world energy con-sumption. Biomass is the main source of the energy for many developing countries, providingmore than 90% of the energy supply in some developing countries. Fuelwood and other biomassfuels are handled and combusted primarily by women, who are largely responsible for repetitivechores, such as cooking, and are often involved in any household industries. Women and children,generally, have the main responsibility for collecting fuel [1734].Among the renewable energy sources, biomass is important because its share of total energy

consumption is still high. Since 1980, the contribution of biomass resources in the total energyconsumption dropped from 20% to 10% in 1998. Biomass in the forms of fuelwood and animalwastes is the main fuel for heating and cooking in many urban areas. The total recoverablebioenergy potential is estimated to be about 16.92 mtoe. The estimate is based on the recoverableenergy potential from the main agricultural residues, livestock farming wastes, forestry and woodprocessing residues and municipal wastes as given in the literature [20]. Table 5 gives the total andrecoverable bioenergy potential of animal wastes, and Table 6 gives total recoverable bioenergypotential in Turkey. Table 7 shows the present and planned biomass energy production in Turkey.Using vegetable oils as fuel alternatives has economic, environmental and energy benets for

Turkey. Vegetable oils have heat contents of approximately 90% of that of Diesel fuel. A major

Table 5

Total and recoverable bioenergy potential of animal wastes in Turkey, 1998

Kind of animal Total number

of animalsa

(thousand head)

Coecient of con-

version (ktoe per

thousand animals)

Total energy

potential (ktoe)

Recoverable

energy potential

(ktoe)

Sheep and goats 75 095 0.048 3604 1081

Donkey, horse, mule and camel 1370 0.235 322 97

Poultry 311 500 0.003 935 281

Cattle and bualo 12 121 0.245 2970 891aData obtained from Ref. [5].


obstacle deterring their use in the direct injection engine is their inherent high viscosities, whichare nearly 10 times that of Diesel fuel. In vegetable oil research, alternative fuel oil studies werealso investigated. In order to have an idea on this subject, the suitability of used frying sunoweroil and crude rape seed oil was investigated. The overall evaluation of the results indicated thatthese oils and biodiesel can be proposed as possible candidates for fuel [27]. On the other hand,organic wastes are of vital importance for the soil, but in Turkey most of these organic wastes areused as fuel through direct combustion. Animal wastes are mixed with straw to increase thecaloric value and are then dried for use. This is the principal fuel of many villages in rural regionsof Turkey, especially in mountainous regions.Anaerobic digestion for methane production is a possible solution to recover the wastes as

fertilizers and produce energy. In Turkey, much eort has been put into biogas research anddevelopment projects since 1960s. In addition to feasibility studies on biogas utilization, manydigesters have been constructed at dierent places in the country. Universities, national researchinstitutes, companies and international organizations have actively been involved with the subject.Unfortunately, due to the lack of collaboration and organization between these dierent projects,further development has not resulted.Fuelwood is important for rural areas in Turkey, as in other developing countries. About half

of the worlds population depends on fuelwood or other biomass for cooking and other domestic

Table 6

Total recoverable bioenergy potential in Turkey, 1998

Type of biomass Energy potential (ktoe)

Dry agricultural residue 4560

Moist agricultural residue 250

Animal waste 2350

Forestry and wood processing residues 4300

Municipality wastes and human extra 1300

Firewood 4160

Total bioenergy 16 920

Table 7

Present and planned biomass energy production in Turkey (ktoe)

Years Classic biomass Modern biomass Total

1999 7012 5 7017

2000 6965 17 6982

2005 6494 766 7260

2010 5754 1660 7414

2015 4790 2530 7320

2020 4000 3520 7520

2025 3345 4465 7810

2030 3310 4895 8205

Total 34 658 17 853 52 511

Source: Ref. [6].


use. In 1998, an estimated 12.5 million steres of fuelwood were produced by the state, while fromboth public and private sectors, the recorded production was estimated at about 14.2 millionsteres from undeclared production [33]. In other words, approximately half of the total demandfor fuelwood is met by informal cutting in State forests and other sources of fuelwood in agri-cultural areas.Although energy forests are considered a renewable energy source, they can disappear in time

due to continued usage and if no improvement studies are made by governments in Turkey. Shortrotation energy forestry involves growing species of willow, planted close together as capping. Thecrop is planted as cuttings using clonal material at around 12 m spacing. Management of thecrop is intensive, with complete weed control absolutely essential if the crop is to be economicallyviable. The crop is harvested on cutting cycles of 46 years, depending on the species and site. Thisis very important for the countrys economic and social conditions. Because the forest cannotsupply enough for heating and cooking purposes, plantations of energy forests should be plannedand implemented very carefully in the country. The harvest intervals of energy forests should belonger than 46 years. The drawback of the longer cutting cycle is that there are bigger gaps in theincome to the villager or farmer in rural areas of Turkey. The economic benets of energy foreststo the country are given in Table 8. As shown in Table 8, at present conditions, approximately500 000 tons of fuelwood can be obtained from 230 000 ha of destroyed energy forests in thecountry [3234].Turkey is a developing country with rich agricultural potential. Important agricultural products

and estimated agricultural residues are given in Table 9. In agricultural residues, the total residuesamount calculated on the dry base has been measured approximately between 40 and 53 milliontons. If it is accepted that 80% of cereal can be used and its average humidity rate is 15%, then thetotal amount of agricultural residues used in power plants would be, as an average, between 27and 36 million tons. As the average energy equivalent of agricultural residues is 17.5 MJ/kg [26],the annual energy equivalent of agricultural residues varies from 470 to 620 PJ. So, agricultural

Table 8

Predictions of energy forest eects on production and contribution to countrys economy in Turkey

Years Forest area

(ha)

Energy forest

area (ha)

From existing forest area From establishing forest area

Mean wood

(ster/ha)

Total wood

(ster)

Mean wood

(ster/ha)

Total wood

(ster)

1990 30 000 34 655 5 150 000 25 866 375

1991 30 000 26 545 5 150 000 35 929 075

1992 35 000 22 530 5 175 000 45 1 013 850

1993 35 000 26 989 5 175 000 55 1 484 395

1994 40 000 13 146 5 200 000 55 723 030

1995 40 000 12 808 5 200 000 65 832 520

1996 45 000 13 004 5 225 000 65 845 260

1997 45 000 5573 5 225 000 79 440 267

1998 50 000 5356 5 250 000 79 423 124

1999 50 000 5240 5 250 000 79 413 960

Total 400 000 165 846 2 000 000 7 971 856

Source: Ref. [32].


residues have a high potential to take the place of lignite (40 million tons) and hard coal (1.3million tons) used in electricity production.Biogas systems are considered to be strong alternatives to the traditional space heating systems

(stoves) in rural Turkey. The economics of biogas systems have been compared with traditionalheating systems fuelled by wood, coal and wood mixture and dried animal waste in three dierentclimatic regions in the country. The technical data used in the analysis were based on experimentalresults. Seven dierent comparisons were made between biogas and traditional systems. Thepayback periods, cumulated life cycle savings and cost of biogas were calculated for a wide rangeusing two unstable economic parameters, discount and ination rates. The quality of the modeland the assumptions were discussed. The results provide evidence of the economic viability ofbiogas systems over the traditional space heating systems of rural Turkey in many instances[17,30].

5. Geothermal energy

Turkey is one of the countries with signicant potential in geothermal energy. Data accumu-lated since 1962 show that there may exist about 4500 MW of geothermal energy usable forelectrical power generation in high enthalpy zones. The heating capacity in the country runs at 350MWt, equivalent to 50 000 households. These numbers can be increased some sevenfold to 2250MWt, equal to 350 000 households, through a proven and inexhaustible potential. Turkey musttarget 1.3 million households, equivalent 7700 MWt. Geothermal central heating, which is lesscostly than natural gas, could be feasible for many regions in the country. In addition, 31 000 MWof geothermal energy potential is estimated for direct use in thermal applications. The totalgeothermal energy potential of Turkey is about 2268 MW in 1998, but the share of geothermalenergy production, both for electrical and thermal uses, is only 1200 MW. There are 26 geo-thermal district heating systems existing now in Turkey. Main city geothermal district heatingsystems are in Goonen, Simav and Krsehir cities [3540].

Table 9

Important agricultural products of Turkey and estimated residue amounts in 1998

Product Harvest area

(1000 ha)

Production

(1000 ton)

Yield (kg/ha) LHV dry basis

(MJ/kg)aEstimated resi-

due amounts

(1000 ton)

Wheat 9400 21 000 2234 18.40 30 00040 000

Barley 3750 9000 2400 17.10 12 00016 000

Oats 158 310 1956 17.70 400600

Rye 133 232 1744 17.60 350450

Rice 60 189 3150 15.40 250350

Maize 550 2300 4182 16.80 40005000

Sunower 586 860 1468 14.28 25003000

Cotton seed 755 1318 1745 17.07 26003100

Sugar beet 505 22 282 44 168 16.72 15002000

Source: Ref. [5].aDry basis (wt.%) LHV lower heating value.


5.1. Geothermal heat pump

Geothermal heat pumps are a relatively new application of geothermal energy that has grownrapidly in recent years. They use the earth as a heat sink in the summer and a heat source in thewinter and, therefore, rely on the relative warmth of the earth for their heating and coolingproduction. On the other hand, the biggest benet of geothermal heat pumps is that they use 2550% less electricity than conventional heating or cooling systems. Geothermal heat pumps canalso reduce energy consumption, and corresponding air pollution emissions, up to 44% comparedto air source heat pumps and up to 72% compared to electric resistance heating with standard airconditioning equipment [41].Detailed technical and economic analyses have been performed for geothermal heat pump

district heating systems for Turkey by several researches that are given in the literature [4244].These studies shows that there is a good potential for geothermal heat pump heating and re-frigeration applications in the country. A study conducted by Kilkis and Eltez [42] show that theuseful energy extracted from a given geothermal reservoir in a district can be increased by 70%through a hybrid/integrated system, when compared to a simple open loop system. Coupled withproper demand side management design, it is projected that about 115% more customers can beserviced with the same amount of geouid extracted, without thermal peaking. This also showsthat when district heating and cooling is involved in a geothermal system, heat pumps and hybridHVAC systems seem to play the key roles.

6. Solar energy

Turkey lies in a sunny belt between 36 and 42N latitudes. The yearly average solar radiationis 3.6 kWh/m2 day, and the total yearly radiation period is approximately 2640 h, which is suf-cient to provide adequate energy for solar thermal applications. Table 10 shows the solar energypotential in Turkey. In spite of this high potential, solar energy is not now widely used, except forat plate solar collectors. They are only used for domestic hot water production, mostly in thesunny coastal regions. In 1998, about 3.0 million m2 of solar collectors were produced, and it ispredicted that the total solar energy production is about 0.080 mtoe [6]. The global solar radiationincident on a horizontal surface and bright sunshine hours are measured by all recording stationsin Turkey. Solar radiation calculations have been performed by several researchers for Turkeythat are given in the literature [4554].

6.1. Solar water heating and energy storage

Although solar energy is the most important renewable energy source, it has not yet becomewidely commercial, even in nations with high solar potential such as Turkey. There are limitedapplications, and most of them are inecient, both in terms of energy use and economical bene-ts. The economical feasibility of a solar energy system is mainly determined by its initial cost andlong term eciency. The cost of the conventional energy replaced by solar means is, of course,another important parameter. Therefore, in the use of solar energy systems, careful considerationis vital to determine the system capacity for optimum useful energy collection at the installation


site [55,56]. On the other hand, thermosyphon type at plate collectors have been used in Turkeysince 1950, and at present, about 30% of the installed systems are still of this type. Typical solarwater heaters in Turkey are of the thermosyphon type and consist of two at plate solar collectors,having an absorber area between 3 and 4 m2, a storage tank (water used as a sensible heat storage(SHS) medium) with capacity between 150200 l and a cold water storage tank, all installed on asuitable frame. The cold water tank is used to store water because, due to shortage problems, thesupply is intermittent. However, the installations are mostly by trial and error. There are quite alarge number of dierent manufacturers producing collectors with varying types and perfor-mances [5761].The eciency and economics of conventional power plants may be improved by using energy

storage. In solar energy, the application of energy storage is required for a reliable energy supply.In this section, only thermal energy storage (TES) will be discussed briey. There are three types ofTES systems: sensible heat, latent heat and thermochemical energy storage. The term SHS refers tosystems that store thermal energy by increasing the temperature of a medium without phasechange, such as melting, boiling or freezing. The amount of energy stored by a sensible heat deviceis proportional to the dierence between the storage input and output temperatures, the mass of thestorage medium and the mediums heat capacity. Each medium has its own advantages, but theadvantages of SHS in liquids include pump ability and high volume utilization. Water usually isthe preferred liquid for temperatures between 0 and 100 C. It is plentiful, essentially free, non-toxic, non-ammable, easily pumped, has excellent thermal properties and is only mildly corrosivein the absence of oxygen. So, in solar water heaters, water is used as the storage medium.Latent heat storage (LHS) is based on the heat absorption and release when a storage material

undergoes a reversible phase change, usually from the solid state to the liquid state in the storage

Table 10

Solar energy potential for seven regions and some cities in Turkey

Region Radiation energy Sunshine duration period

Average

(kWh/m2 y)

Maximum

(kWh/m2 y)

Minimum

(kWh/m2 y)

Average (h/y) Maximum

(h/month)

Minimum

(h/month)

Southeast An-

atolia

1492 2250 600 3016 408 127

Diyarbakr 1448 2400 620 2947 390 112

Mediterra-

nean

1453 2112 588 2924 360 102

Antalya 1378 2160 528 3062 386 140

Central Ana-

tolia

1434 2112 504 2712 381 98

Ankara 1492 2448 506 2662 380 80

Aegean 1407 2028 492 2726 371 96_IIzmir 1230 1965 456 2770 387 109East Anatolia 1395 2196 588 2694 374 167

Erzurum 1299 2016 580 2618 354 100

Marmara 1144 1992 396 2528 351 88_IIstanbul 1329 2220 456 2370 357 78Black Sea 1086 1704 408 1966 274 84

Trabzon 1009 1728 420 1672 202 96


charging mode and vice versa in the storage discharging mode. The storage material used is calleda phase change material (PCM). Typical materials are water/ice, salt hydrates, paran wax andcertain polymers. The energy densities for LHS are greater than those for SHS, resulting insmaller and lighter storage devices and lower storage losses. The relatively constant temperatureof storage can maximize collector eciency and minimize storage heat loss. Especially in a solarassisted heat pump system for domestic heating, the PCM stores energy from the solar collectorsas a latent heat at a nearly constant transition temperature (during melting and solidication). Itcan be used more preferably as a heat source than water and rock storage for a heat pump becausethe energy storage temperature of the PCM is around 2535 C for both calcium chloridehexahydrate and sodium sulfate decahydrate (these salt hydrates are the ones most commonlyused). These temperature intervals are suitable for solar assisted heat pump applications in themoderate climatic regions of Turkey [6267].Many PCMs have been investigated. While many studies on phase change TES systems have

been performed at relatively low temperatures (below 100 C) for heat storage in home heatingand cooling units, studies are sparse for higher temperature heat (about 200 C) used for somesolar energy systems and also for intermediate-temperature phase change TES. An ideal PCMmust have the following features: appropriate phase change temperature, high latent heat, lowcost, ready availability, non-toxicity and non-ammability, uniform phase change characteristics(no subcooling or separation) and long life under repeated phase change [6871].

6.2. Solar drying

Sun drying of agricultural products has been practised all over the world since the dawn ofcivilisation. The methods generally used for basic drying processes were simple, more labourintensive and less quality control oriented. The characteristic technical problems faced by basicsun drying processes were: (a) cloudiness and rain, (b) insect infestation, (c) high level of dust andatmospheric pollution and (d) intrusion from animals and man. However, with the general de-velopment of knowledge and technology, human endeavours have been directed forward sup-planting the traditional drying of crops with certain articial means in order to achieve betterquality control, to reduce spoilage and to lessen the losses and ineciencies of the traditional sundrying methods [7274].Drying has a long tradition as a conservation method in Turkey. During the drying season,

insect and mold development in harvested crops is promoted due to the high air temperature andrelative humidity. Furthermore, intensive solar radiation causes several quality reductions, likevitamin losses or color changes, in dried crops. In Turkey, solar energy has been used since thedawn of history for open air drying of agricultural products, such as hazelnut, beans and a varietyof other products. There is enough potential for solar drying in Turkey, and this applicationshould be increased by government and private companies [7579].

6.3. Solar heat pump combination

The largest number of heat pumps currently being used are small reversible units, which canprovide both heating and cooling in individual rooms, houses, shops, oces, schools and insti-tutional buildings. Annually, over 10 million units are produced worldwide, and over 65 million


units are in operation in Japan, the USA, China and Europe. These heat pumps are cost eectivein many regions of the world, as they cost little extra compared to a cooling-only air conditioner.On the other hand, in cold to moderate climates, heating-only heat pumps are used to heat tapwater and homes. In commercial buildings and industrial processes, heat pumps are often appliedwhere simultaneous heating and cooling is required, or heating in winter and cooling in summer.Worldwide, over 10 million systems are installed in commercial and institutional buildings [31].Experimental and theoretical studies have been performed by several researchers [8089] for

solar heat pump combinations in Turkey. Solar energy and heat pump systems are two promisingmeans of reducing the consumption of fossil fuel resources and, hopefully, the cost of deliveredenergy for residential heating. An intelligent extension of each is to try to combine the two inorder to further reduce the cost of delivered energy. Solar heat pump systems can be classied,according to the source of heat that supplies the evaporator of the heat pump, as either parallel,series or dual. In parallel systems, the heat pump receives energy from the outdoor air, and thecollected solar energy is supplied directly for either space heating or for heating water. In the seriessystem, solar energy is supplied to the evaporator of the heat pump, thereby raising its temper-ature and increasing the coecient of performance. In the dual source conguration, the evap-orator is designed so that it can receive energy from either the outdoor air or from the solar energystore. Our studies show that there is a great potential for using a solar heat pump combination fordomestic heating/cooling applications in Turkey.

6.4. Photovoltaic energy

Turkey, currently, does not have an organized PV program. Global energy strategies andpolicies are laid down in periodic ve year development plans. The government has no intention inPV production. On the other hand, it encourages investment in the energy sector by some -nancial incentives. Plans for industrial scale production of PV modules are concentrated in thinlm areas rather than crystalline materials. PV cells are produced in various research establish-ments in order to study the feasibility of local manufacturing. So far, none of these studies yieldeda positive result in order to justify a mass production facility in Turkey. The potential of Turkeyas a PV market is very large, since the country is very suitable in terms of insolation and largeavailable land for solar farms. There are more than 30 000 small residential areas where solarpowered electricity would likely be more economical than grid supply. Another potential for thePV market is holiday villages at the long coastal areas. These facilities are frequently far from themain grid nodes and require additional power when solar insolation is high. Unfortunately, en-ergy demand in Turkey is so large that utilities are concentrating on large conventional powerplants and peak load facilities. The newest ve year development plan being prepared foresees amore ambitious program and estimates approximately 40 MW installed power by the year 2010[9092].

7. Wind energy

More than 20 000 wind turbines are in use around the world for generating electricity and overa million for pumping water. Although experimental wind turbines up to several megawatts in size


have been built, the optimum size currently appears to be around 300500 kW. There are manyareas in which wind energy is plentiful. In Europe, it has been estimated that as much as 25% of itscurrent electricity demand could be met from wind energy sources, once technical and environ-mental constraints have been taken into account [4].There are a number of cities in Turkey with relatively high wind speeds (see Table 11). These

have been classied into six wind regions, with a low of about 3.5 m/s and a high of 5 m/s at 10 maltitude, corresponding to a theoretical power production between 1000 and 3000 kWh/(m2 y).The most attractive sites are the Marmara Sea region, Mediterranean Coast, Aegean Sea Coastand the Anatolia inland [9398]. Turkeys rst wind farm was commissioned in 1998 and has acapacity of 1.5 MW. The capacity is likely to grow rapidly, as plans have been submitted for justunder a further 600 MW of independent facilities. The majority of the proposed projects arelocated in the C esme, _IIzmir and Canakkale regions. The electrical power resources survey anddevelopment administration (EIE) conducts wind measurements at various locations to evaluatethe wind energy potential over the country and has started to compile a wing energy atlas (incooperation with other organisations). Approval of independent wind energy projects requires atleast a six months history of wind measurements.

Table 11

Wind characteristics for some selected cities in Turkey

Station name Latitude N

(degree)

Longitude E

(degree)

Altitude (m) Average

energy densiy

(W/m2)

Average wind speed (m/s)

At 5 m At 50 m

Akhisar 38.55 27.51 93 44 2.7 4.0

Anamur 36.06 32.50 5 52 3.1 4.3

Antakya 36.12 36.10 100 84 4.0 5.8

Ayvalk 39.19 26.42 4 54 3.1 4.2

Balkesir 39.38 27.53 147 58 2.8 4.2

Bandrma 40.21 27.58 58 301 5.8 6.9

Bergama 39.01 27.11 45 61 3.5 4.9

Bodrum 37.02 27.26 27 85 3.7 5.1

Bozcaada 39.50 26.04 40 317 6.2 8.4

Canakkale 40.08 26.24 2 92 3.9 5.4Corlu 41.10 27.47 183 103 3.8 5.3Etimesgut 39.57 32.40 806 49 2.5 3.1

Gookceada 40.12 25.54 72 70 3.5 5.5_IInebolu 41.59 33.46 64 63 3.7 5.2Karapnar 37.43 33.33 997 45 2.8 3.9

Malatya 38.21 38.19 898 51 2.7 3.7

Mardin 37.18 40.44 1080 114 4.3 6.0

Samsun 40.21 36.15 44 41 2.7 3.6

Saryer 41.10 29.03 56 42 2.9 4.1

Seydisehir 37.25 31.51 1131 45 2.7 3.8Silifke 36.23 33.56 15 50 2.9 3.9

Sinop 42.02 35.10 32 84 3.6 5.1


8. Conclusions

To achieve even the modest environmental goals of the Kyoto Protocol accords requires thesustained and orderly commercial development of viable renewable energy options. It is not en-ough for governments to support the development of renewable energy technologies. They mustalso support their commercial application in the country. If support of renewable energy researchand development is an appropriate use of public funds, so too is purchasing the fruits of theseresearch programs. Like health care, education, construction and maintenance of roads andnational defence, renewable energy is a public good. In the case of Turkey, due to some tech-nological and economical consequences, renewable energy resources do not have wide applica-tions, but renewable energy usage should be increased year by year by government and privatecompanies because Turkey is an energy importing country and domestic fossil fuels are limitedand the economical condition of the country is not good. The present study shows that there is animportant potential to use renewable energy for Turkey. Especially hydropower, biomass, geo-thermal, solar and wind energy seem to be the most interesting domestic and clean energy sources.So, a step-wise (i.e. combined use) shift from fossil fuels to renewable ones seems to be serious andthe sole alternative for Turkey.

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Renewable energy potential and utilization in TurkeyIntroductionPresent energy use in TurkeyWater potential in TurkeyHydroelectricitySoutheastern Anatolia project (GAP)

BiomassGeothermal energyGeothermal heat pump

Solar energySolar water heating and energy storageSolar dryingSolar heat pump combinationPhotovoltaic energy

Wind energyConclusionsReferences

renewable energy potential and utilization in turkey

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