Development of geothermal energy utilization in Turkey: a review

Renewable energy is accepted as a key source for the future, not only for Turkey but also for the world. Turkey has a considerably high level of renewable energy sources that can be a part of the total energy network in the country. 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. The share of its potential used is, however, only about 2–3%.The main objective of the present study is to review the development of geothermal energy (GE) utilization in Turkey, giving its historical development and opportunities. GE is used for electric power generation and direct utilization in Turkey, which is among the first five countries in the world in geothermal direct use applications. Direct use of geothermal resources has expanded rapidly last 36 years from space heating of single buildings to district heating, greenhouse heating, industrial usage, modern balneology and physical treatment facilities.Turkey presently has one operating geothermal power plant, located near Denizli City in Western Anatolia with an installed capacity of 20.4 MW_e and an electrical energy production of 89,597 MW h in 2001. Recently, the total installed capacity has reached 820 MW_t for direct use. The total area of geothermal heated greenhouses exceeded over 35 ha with a total heating capacity of 81 MW_t. Ground-source (or geothermal) heat pumps (GSHPs) have also been put on the Turkish market since 1998. Though there are no Turkish GSHP manufactures as yet, 207 units have been installed in the country to date, representing a total capacity of 3 MW.GE is a relatively benign energy source, displaying fossil fuels and thus reducing greenhouse gas emissions. So, it is expected that GE development will significantly speed up in the country if the geothermal law becomes effective.     

Geothermal energy potential for power generation in Turkey: A case study in Simav,Kutahya

Geothermal energy and the other renewable energy sources are becoming attractive solutions for clean and sustainable energy needs of Turkey. Geothermal energy is being used for electricity production and it has direct usage in Turkey, which is among the first five countries in the world for the geothermal direct usage applications. Although, Turkey is the second country to have the highest geothermal energy potential in Europe, the electricity production from geothermal energy is quite low. The main purpose of this study is to investigate the status of the geothermal energy for the electricity generation in Turkey. Currently, there is one geothermal power plant with an installed capacity of 20.4 MWe already operating in the Denizli–Kizildere geothermal field and another is under the construction in the Aydin–Germencik field.This study examines the potential and utilization of the existing geothermal energy resources in Kutahya–Simav region. The temperature of the geothermal fluid in the Simav–Eynal field is too high for the district heating system. Therefore, the possibility of electrical energy generation by a binary-cycle has been researched and the preliminary feasibility studies have been conducted in the field. For the environmental reasons, the working fluid used in this binary power plant has been chosen as HCFC-124. It has been concluded that the Kutahya–Simav geothermal power plant has the potential to produce an installed capacity of 2.9 MWe energy, and a minimum of 17,020 MWh/year electrical energy can be produced from this plant. As a conclusion, the pre-feasibility study indicates that the project is economically feasible and applicable.     

Research on the generation of electricity from the geothermal resources in Simav region, Turkey

One of the greatest problems in using renewable energy sources is the great variability of energy level, both in the short and long term. Geothermal energy, by nature, has high availability because the source is not dependent on weather conditions, so it is among the most stable renewable energy sources. Geothermal energy has the potential to play an important role in the future energy supply of Turkey. Although Turkey has the second-highest geothermal energy potential in Europe, electricity generation from geothermal energy is rather low.This study examines the use of geothermal energy in electricity generation and investigates the applicability of the existent geothermal energy resources to electricity generation in the Kütahya–Simav region, Turkey. The binary cycle is used in the designed power plant for electricity generation from geothermal fluid in which the percentage of liquid is high and which is at lower temperature. In this power plant, R134a is chosen as the secondary fluid, whose boiling point temperature is lower than that of water, and is used instead of geothermal fluid in a second cycle. The thermal efficiency of the designed power plant is measured to be 12.93%.     

Investigation of coal-fired power plants in Turkey and a case study: Can plant

About 61% of the total installed capacity for electrical power generation in Turkey is provided by thermal resources, while 80% of the total electricity is generated from thermal power plants. Of the total thermal generation, natural gas accounts for 49.2%, followed by coal for 40.65%, and 9.9% for liquid fuel. This study deals with investigation of the Turkish coal-fired power plants, examination of an example plant and rehabilitation of the current plants. Studied plant has a total installed capacity of 2 × 160 MW and has been recently put into operation. It is the first and only circulating fluidized bed power plant in the country. Exergy efficiencies, irreversibilities, and improvement factors of turbine, steam generator and pumps are calculated for plant selected. Comparison between conventional and fluidized bed power plant is made and proposed improving techniques are also given for conventional plants.     

Efficiency improvement for geothermal power generation to meet summer peak demand

Geothermal power is an important part of New Zealand's renewable electricity supply due to its attractive cost and reliability. Modular type binary cycle plants have been imported and installed in various geothermal fields in New Zealand, with plans for further expansion. Power output of these plants deteriorates in the summer because plant efficiency depends directly on the geothermal resource and the ambient temperature. As these plants normally use air-cooled condensers, incorporating a water-augmented air-cooled system could improve the power output in summer thereby matching the peak air-conditioning demand. In this work, power generation for the Rotokawa plant was characterized using a similar plant performance and local weather. The improved performance was modelled for retrofit with a wet-cooling system. Maximum generation increase on the hottest day could be 6.8%. The average gain in power over the summer, November–February, was 1.5%, and the average gain for the whole year was 1%. With current binary unit generation capacity at the Rotokawa plant of 35 MW, investment in a water-augmented air-cooled system could provide 2 MW of peak generation on the hottest days. This investment in efficiency is found to compare favourably to other supply options such as solar PV, wind or gas.     

Exergoeconomic evaluation of electricity generation by the medium temperature geothermal resources,using a Kalina cycle: Simav case study

Recent technical developments have made it possible to generate electricity from geothermal resources with low and medium enthalpy. One of these technologies is the Kalina Cycle System (KCS-34). In this study, electricity generation from Simav geothermal field is investigated. The optimum operating conditions for the KCS-34 plant design are determined on the basis of the exergetic and life-cycle-cost concepts. With the best design, power generation of 41.2 MW and electricity production of 346.1 GWh/a can be obtained with an energetic efficiency of 14.9% and exergetic efficiency of 36.2%. It is shown that, with the currently prevailing interest and inflation rates, the plant designs considered are economically feasible for values of the present worth factor (PWF) higher than 6.     

Combined cycle versus one thousand diesel power plants: pollutant emissions,ecological efficiency and economic analysis

The increase in the use of natural gas in Brazil has stimulated public and private sectors to analyse the possibility of using combined cycle systems for generation of electrical energy. Gas turbine combined cycle power plants are becoming increasingly common due to their high efficiency, short lead times, and ability to meet environmental standards. Power is produced in a generator linked directly to the gas turbine. The gas turbine exhaust gases are sent to a heat recovery steam generator to produce superheated steam that can be used in a steam turbine to produce additional power. In this paper a comparative study between a 1000 MW combined cycle power plant and 1000 kW diesel power plant is presented. In first step, the energetic situation in Brazil, the needs of the electric sector modification and the needs of demand management and integrated means planning are clarified. In another step the characteristics of large and small thermoelectric power plants that use natural gas and diesel fuel, respectively, are presented. The ecological efficiency levels of each type of power plant is considered in the discussion, presenting the emissions of particulate material, sulphur dioxide (SO₂), carbon dioxide (CO₂) and nitrogen oxides (NO_x).     

Sustainable development of Turkey: Deployment of geothermal resources for carbon capture,utilization, and storage

As a developing country, Turkey’s sustainable development objectives converge on robust and sustainable economic development. The increase in its energy and electricity demand is attributed to the growth of population, urbanization, and industrialization parallel to economic and social growth. Instead of fulfilling the obligation to protect the environment arising from international agreements and achieving desired sustainable development, the dependency on imported fossil fuel in electrical energy production and energy-intensive economic growth results in intensified CO₂ emission as well as ironically negative economic output. Therefore, Turkey is forced to exploit its indigenous sources such as coal (which unfortunately increases atmospheric Green House Gas “GHG” emissions) and renewable resources. However, high GHG emission – mainly CO_{2 –} of Turkey’s coal power plants impairs deployment of indigenous sources for power generation. Indeed, there is a necessity of technical approaches for higher heat extraction efficiencies and mitigation of high concentration of energy-related CO₂ emission. Admittedly, “Carbon Capture, Utilization, and Storage (CCUS)” employing conventional hydrothermal resources offers highly efficient heat extraction, geological CO₂ sequestration, and utilization of CO₂ for power generation rather than considering CO₂ as an effluent. Although there are research gaps and lack of field scale experiment, the economic and environmental viability of implementing CCUS in Turkey can be improved by pilot or field scale projects whereby the presence of these projects commences technological and experimental advances in capturing CO₂ either from geothermal power plants or indigenous coal power plants, transporting it to the proven geothermal geologic site, and generating power. Apart from this, the “CO_{2 –} Plume Geothermal Systems (CPG)” compared to unconventional and conventional geothermal systems would commit vigorous potential for continual improvement in economic feasibility of CCUS without a guaranteed return on power generation investments in Turkey. Hence, legislations concerning incentives in CCUS would foster further improvements in the deployment of geothermal resources to pursue sustainable development in Turkey.     

Geothermal electric power in Iceland: Development in perspective

Geothermal energy is extensively used in thermal (direct) applications in Iceland. More than 70% of the total population enjoy geothermal district heating. Hydro-power provides most of the electricity generated in Iceland, with less than 10% of the potential harnessed. Iceland is well endowed with both geothermal (high- and low-temperature) and hydro-power resources. At the end of 1980, the installed geothermal power in Iceland was 818 MW₁ in direct applications and 41 MW_e in electric power generation. This exploitation represents a few percent of the estimated geothermal resources of Iceland. Plans to develop geothermal electric power in Iceland date back to the early 1960s. The first geothermal electric power plant (3 MW_e) was installed in 1969. In recent years, several small-scale (two 1 MW_e and one 6 MW_e) geothermal power units have been installed in a cogeneration plant for district heating purposes. There is one major (30 MW_e) geothermal electric power plant in Iceland, which became operational in 1978. Hydro-power, geothermal energy and oil provide consumers in Iceland with about 18, 38, and 44% of their energy needs, respectively.     

Geothermal energy in Turkey: 2008 update

Geological studies indicate that the most important geothermal systems of western Turkey are located in the major grabens of the Menderes Metamorphic Massif, while those that are associated with local volcanism are more common in the central and eastern parts of the country. The present (2008) installed geothermal power generation capacity in Turkey is about 32.65 MWe, while that of direct use projects is around 795 MWt. Eleven major, high-to-medium enthalpy fields in western part of the country have 570 MWe of proven, 905 MWe of probable and 1389 MWe of possible geothermal reserves for power generation. 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.     

Cost evaluation of two potential nuclear power plants for hydrogen production

Hydrogen is recognized as one of the most promising alternative fuels to meet the energy demand for the future by providing a carbon-free solution. In regards to hydrogen production, there has been increasing interest to develop, innovate and commercialize more efficient, effective and economic methods, systems and applications. Nuclear based hydrogen production options through electrolysis and thermochemical cycles appear to be potentially attractive and sustainable for the expanding hydrogen sector. In the current study, two potential nuclear power plants, which are planned to be built in Akkuyu and Sinop in Turkey, are evaluated for hydrogen production scenarios and cost aspects. These two plants will employ the pressurized water reactors with the electricity production capacities of 4800 MW (consisting of 4 units of 1200 MW) for Akkuyu nuclear power plant and 4480 MW (consisting of 4 units of 1120 MW) for Sinop nuclear power plant. Each of these plants are expected to cost about 20 billion US dollars. In the present study, these two plants are considered for hydrogen production and their cost evaluations by employing the special software entitled “Hydrogen Economic Evaluation Program (HEEP)” developed by International Atomic Energy Agency (IAEA) which includes numerous options for hydrogen generation, storage and transportation. The costs of capital, fuel, electricity, decommissioning and consumables are calculated and evaluated in detail for hydrogen generation, storage and transportation in Turkey. The results show that the amount of hydrogen cost varies from 3.18 $/kg H₂ to 6.17 $/kg H₂.     

Indonesian geothermal development in the national energy scenario. Development program to the year 2000

The electric power sector in Indonesia will be expanded with an additional generating capacity of about 5256 MW at the end of the Fourth Five-Year Development Plan 1984/85 — 1988/89 from the existing 3912 MW. At present a 30 MW geothermal condensing plant and two non-condensing of 2 MW and 0.25 MW have been operating successfully since 1983. Geothermal energy will be developed primarily for electric power and a total of 220 MW and 660 MW will be added during the 4th (1984 — 89) and 5th (1989 — 94) Five Year Plans, reaching a total capacity of nearly 1000 MW. The government will accelerate geothermal exploration of 18 areas in Sumatera, 29 in Java, 16 in Sulawesi and 14 areas in Bali, the Lesser Sunda islands and Moluccas.     

Future of renewable energies in Iran

The activities in field of renewable energy in Iran are focused on scientific and research aspects, and research part is aimed at reduction of capital required for exploitation of related resources. The second step is to work research results into scientific dimension of this field for practical means, i.e. establishing electricity power plants. Due to recent advancements in wind energy, many investors in the country have become interested in investing in this type of energy. At the moment, projects assuming 130 MW of wind power plants are underway, of which, 25 MW is operational. Based on the planning in the 4th Socioeconomic and Cultural Development Plan (2005–2010), private sector is expected to have a share of at least 270 MW in renewable energies. However, it is the government's duty to take the first step for investment in biomass and solar power plants; private sector may then play its part once the infrastructures to this end are laid out. At the moment, a 250 kW plant is under construction in Shiraz and two more geothermal units with 5 and 50 MW capacities will follow. Moreover, two biomass and solar energy plants, standing at 10 and 17 MW, respectively, are of other upcoming projects. The project of Iran's renewable energy, aims to accelerate the sustainable development of wind energy through investment and removal of barriers. This preparatory project is funded by the global environment facility (GEF) and will provide for a number of international and national consultant missions and studies. Once the studies are concluded, a project to develop 25 MW of wind energy in the Manjil region of Gilan will be prepared. It will be consistent with the national development frameworks and objectives and form part of 100 MW of wind-powered energy, which is expected to be developed under the government's third 5-year national development plan (started 21 March 2000).     

Current Geothermal Energy Potential in Turkey and Use of Geothermal Energy

Turkey is the seventh-richest country in the world in geothermal potential. The first geothermal researches and investigations in Turkey started by the Turkey Mineral Research and Exploration Institute (MTA) in the 1960s. Upon this, 170 geothermal fields have been discovered by MTA, in which 95% of them are low-medium enthalpy fields, which are suitable mostly for direct-use applications. The overall geothermal potential in Turkey is about 38,000 MW. Of this potential, around 88% is appropriate for thermal use (temperature less than 473 K) and the remainder is appropriate for electricity production (temperature more than 473 K). Turkey has extended its involvement in geothermal energy projects, supported by loans from the Ministry of Environment, and geothermal energy is expected to increase substantially in the coming years. Overall, Turkey has an estimated 4,500 MW of geothermal power production potential.     

Geothermal energy utilization in Turkey

This paper investigates the status of geothermal development in Turkey as of the end of 1999. Turkey is one of the countries with significant potential in geothermal energy. Resource assessments have been made many times by the Mineral Research and Exploration Directorate (MTA) of Turkey. The main uses of geothermal energy are mostly moderate‐ and low‐temperature applications such as space heating and domestic hot water supply, greenhouse heating, swimming and balneology, industrial processes, heat pumps and electricity generation. The data accumulated since 1962 show that the estimated geothermal power and direct use potential are about 4500 MW_e and 31 500 MW_t, respectively. The direct use capacity in thermal applications is in total 640 MW_t representing only 2 per cent of its total potential. Since 1990, space heating and greenhouse developments have exhibited a significant progress. The total area of greenhouses heated by geothermal energy reached up to about 31 ha with a heating capacity of 69.61 MW_t. A geothermal power plant with a capacity of 20.4 MW_e and a CO₂ factory with a capacity of 40000 ton yr^?1 have been operated in the Denizli‐Kizildere field since 1984 and 1986, respectively. Ground source heat pumps have been used in residential buildings for heating and cooling for approximately 2 years. Present applications have shown that geothermal energy in Turkey is clean and much cheaper compared to the other energy sources like fossil fuels and therefore is a promising alternative. As the projects are recognized by the public, the progress will continue. Copyright © 2001 John Wiley & Sons, Ltd.     

Investigation of hydrogen production performance of chlor-alkali cell integrated into a power generation system based on geothermal resources

In present study, hydrogen production performance of chlor-alkali cell integrated into a power generation system based on geothermal resource is studied. The basic elements of the novel system are a separator, a steam power turbine, an organic Rankine cycle (ORC), an air cooled condenser, a saturated NaCl solution reservoir tank and a chlor-alkali cell. To enhance the performance of the cell, the saturated NaCl solution is heated by the waste heat from the ORC. So, this integrated system generates significant amount of electricity for the city grid and also yields three main products those are hydrogen, chlorine and sodium hydroxide. According to the parametric study, when the temperature of a geothermal resource varies from 140 to 155 °C, the electrical power generation increases from nearly 2.5 MW to 3.9 MW and hydrogen production increases from 10.5 to 21.1 kg-h. Thus, when the geothermal resource temperature of 155 °C, the energy efficiency of the system is 6.2% and the exergetic efficiency is 22.4%. As a result, the geothermal energy potential plays a key role on the integrated system performance and the hydrogen production rate.     

The Bad Blumau geothermal project: a low temperature, sustainable and environmentally benign power plant

The 250 kW geothermal project at Bad Blumau is the first geothermal project developed in Austria by the private sector following the deregulation of the electricity industry in this country. What makes the project unique besides its private ownership structure is its ability to generate electrical power and district heating for the Rogner Bad Blumau Hotel & Spa by using a low temperature geothermal resource. Installed in the record time of less than a week, the air-cooled ORMAT ® Energy Converter (OEC) CHP module has been in commercial operation since July 2001. With an annual availability exceeding 99%, between October 2001 and December 2002 the plant delivered 1,560,000 kWh to the local grid. The geothermal CHP module utilizes brine at 110 °C, available from a 3000 m deep production well. Exiting the OEC unit at a temperature of 85 °C, the brine is then fed into the district heating system, providing heat for the Rogner Bad Blumau Hotel & Spa. The geothermal brine is returned from the district heating system and injected into a 3000 m depth reinjection well. The system is a pollution-free, unattended operating power generation module, which has avoided more than 1100 kg of CO₂ emissions over its first operating year.     

Evaluation of wind energy investment interest and electricity generation cost analysis for Turkey

Turkey has remarkable wind energy potential, but its utilisation rate is very low. However, in 2007, energy investors applied to the Energy Market Regulatory Authority (EMRA) with 751 wind projects to obtain a 78180.2 MW wind power plant license. This paper first presents an overview of wind energy development in the world and then reviews related situations in Turkey. Second, to motivate the interest in wind energy investment, new wind power plant license applications in Turkey are analysed. Finally, wind electricity generation cost analyses were performed at 14 locations in Turkey. Capacity factors of investigated locations were calculated between 19.7% and 56.8%, and the production cost of electrical energy was between 1.73 and 4.99 $cent/kW h for two different wind shear coefficients.     

Exergy based fluid selection for a geothermal Organic Rankine Cycle for combined heat and power generation

In this study the option of combined heat and power generation was considered for geothermal resources at a temperature level below 450 K. Series and parallel circuits of an Organic Rankine Cycle (ORC) and an additional heat generation were compared by second law analysis. Depending on operating parameters criteria for the choice of the working fluid were identified. The results show that due to a combined heat and power generation, the second law efficiency of a geothermal power plant can be significantly increased in comparison to a power generation. The most efficient concept is a series circuit with an organic working fluid that shows high critical temperatures like isopentane. For parallel circuits and for power generation, fluids like R227ea with low critical temperatures are to be preferred.     

Experimental results of silica removal from simulated solutions of geothermal brine of Kizildere field,Turkey

The Denizli-Kizildere geothermal power plant in western Anatolia, Turkey, has a capacity of 20 MW. The waste brine from the plant has a flow rate of 1500 ton/h and contains approximately 400 mg/dm³ of silica, which causes scaling. This paper describes experimental work carried out to investigate the optimum conditions of silica removal from Denizli-Kizildere geothermal wastewater by precipitation.