Geothermal Project Development in Turkey — An Overview With Emphasis on Drilling

Turkey, a net oil and gas importer, has recently attracted considerable private investments in renewable energy, including hydro, wind and geothermal. Geothermal exploration in Turkey started in the early 1960s. The first use of geothermal resources dates back to the central heating system of the Gönen Park Hotel in 1964. The first geothermal well in a high enthalpy field for potential power production was drilled in 1968; it had a depth of 540 m and a temperature of 198 °C. Turkey has enough geothermal reserves to satisfy the heat requirements of 1.2 million homes. Analysts estimated the country’s potential to be between 1000 MWe and 2000 MWe. Considering the size of Turkey’s geothermal resources, the current development of this clean and renewable resource is still far below an expected level. However during the last two decades, there has been a remarkable increase in the use of geothermal for heating purposes and for electricity generation, which started in 2007. Since 1963, between 850 and 900 geothermal wells have been drilled. The Turkish Government has recently enacted the Renewable Energy Law, which includes geothermal, and has introduced several incentives to promote the renewable energy market. Turkey issued the Geothermal Energy Resources Law in June 2007, which was enacted a year later, in June 2008. Besides the current Geothermal Law, new amendments to the Renewable Energy Law have already helped the implementation of geothermal with a purchase warranty. Based on recent industry developments, it is clear that geothermal will contribute significantly to Turkey’s future energy supply. The Geothermal Energy Law regulates geothermal resources, natural mineral water resources and geothermal-related gases in terms of ownership rights, licenses, and their assignment and transfer. After 2007, when the Geothermal Law became effective, the number of geothermal exploration and drilling projects has grown in Turkey. A significant increase in deep and highenthalpy well drilling has been observed after the Renewable Energy Law No. 6094 (the “Amending Law”) came into effect on 8 January 2011. The Amending Law introduced further USD Fixed Price incentives to encourage investments; i.e., for geothermal power: 10.5 US¢/kWh for the first 10 years after the plants came on line and a, purchase warranty for the electricity that was generated. This paper reviews geothermal project development in Turkey, with emphasis on drilling activities, particularly on drilling statistics, success rates, rig costs and average penetrating rates. The case histories of the Menderes and Alaşehir/Gediz graben drilling activities are used to illustrate some of the concepts. Forty eight geothermal wells have been drilled by the Turkish Petroleum International Company (TPIC), which was established in 1988 as a subsidiary of the Turkish Petroleum Corporation (TPAO) to operate in all branches of the oil industry, comprising mainly exploration, drilling, field development, production, transportation, refining, crude oil and oil products trading and distribution. Besides the oil well drilling services, TPIC has conducted geothermal drilling activities and is very active in geothermal services (work over, cementing, well testing, wire line services, directional drilling etc.). TPIC should have successfully completed almost 120,000 m of geothermal well drilling by the end of May 2012. (Kaya 2011)