Lignite resources of Turkey: Geology, reserves, and exploration history Volkan Ş. Ediger a, ⁎, Istemi Berk b , Ayhan Kösebalaban c a Kadir Has University, Kadir Has Street, Cibali, 34083 Istanbul, Turkey b Institute of Energy Economics, University of Cologne, Vogelsanger Str. 321, 50827 Cologne, Germany c Turkish Coal Enterprises (TKİ), Hipodrom Cad. No. 12, Yenimahalle, 06330 Ankara, Turkey abstract article info Article history: Received 27 February 2014 Received in revised form 4 June 2014 Accepted 10 June 2014 Available online 17 June 2014 Keywords: Lignite Geology Reserve classification Exploration history Turkey This article aims to emphasize the importance of lignite, which is the mostly used domestic energy source in the Turkish energy mix, by briefly overviewing its geology, reserves, and exploration. Lignites are distributed in mostly continental sedimentary basins of Tertiary age all over the country. The lignite-bearing basins display the characteristics of different geological settings, of which grabens and half-grabens are the most common ones especially in western Anatolia. The geological and chemical characteristics of Turkish lignites do not only create some important problems during mining and coal preparation but also make them unfavorable for con- sumption. However, since they are the most valuable energy resource of the country they should benefit the economy in the most efficient and environmentally friendly way. Moreover, two most important conclusions of this study are as follows: firstly, reserve estimation practices in the country should definitely be revised to pro- vide a more realistic evaluation of the country's lignite potential for developing medium- and long-term energy strategies and policies for decision- and policy-makers. Secondly, exploration and development activities should be coordinated by a single institution, most likely a government institution, as has been the case for some 50 years. © 2014 Elsevier B.V. All rights reserved. 1. Introduction As the major indigenous energy source of the country, lignite, consti- tuting up to 20.9% in 1986 of the energy mix of Turkey, has always been very important. Recently, although its share is increasing from a histor- ical minimum of 10.2% in 2005 to 14% in 2012, the share of hard coal has almost doubled by increasing from 8.8% to 16.7% between 1978 and 2012, making it more important than lignite. However, lignite is the big- gest national energy resource whereas hard coal is import-dependent at the rate of 94.7% by 2012. This is a very controversial policy for a country whose dependency on foreign energy sources has already reached 75.9% by 2012. This article, therefore, attempts to emphasize the impor- tance of lignite as the major domestic energy source in the Turkish en- ergy mix by briefly overviewing its geology, reserves, and exploration. The upstream sector of the Turkish lignite industry is traditionally dominated by state-owned enterprises, such as the General Directorate of Mineral Research and Exploration (MTA), the General Directorate of Turkish Coal Enterprises (TKİ), and Electricity Generation Company (EÜAŞ). However, while TKİ and EÜAŞ are responsible for lignite pro- duction and electricity generation from lignite, MTA was established to conduct reconnaissance, appraisal, and exploration activities for coal among other minerals. For this reason, most research and explora- tion activities, including geological mapping, geochemical analyses, geophysical studies, exploratory drilling, etc. have been carried out by MTA since its establishment in 1935. However, after the establishment of TKİ in 1957 and TTK (Turkish Hard Coal Enterprises) in 1983, some of MTA's duties have been transferred to these enterprises. After it was delegated responsibility for the lignite fields feeding coal-fired power plants, EÜAŞ became not only the second biggest lignite produc- er after TKİ, but also the public company with the largest lignite reserves in Turkey especially after 2005. Since TKİ has historically been the major lignite supplier to industry, this study concentrates on its reserves and upstream activities. The rel- evant activities of other state-owned enterprises and private companies are also included wherever data is available. The data presented in this study is mostly obtained from TKİ within the framework of the project “History of Turkish Coal Enterprises (TKİ) and Turkish Hard Coal Enter- prises (TTK), and Turkish Coal Strategies”. Other data including previous reports and publications are also used in various extents. Therefore, unless otherwise stated the data is from Ediger (2014). Although they can also be traced back to the late 19th century, modern and well-documented lignite exploration activities started in the 1970's as summarized in TKİ (1973). From this perspective, Lignite Inventory of Turkey published in 1986 has been a milestone as far as geology and reserves of Turkish lignites are concerned. The report International Journal of Coal Geology 132 (2014) 13–22 ⁎ Corresponding author at: Kadir Has University, Energy Systems Engineering Department, Kadir Has Street, Cibali, 34083 Istanbul, Turkey. E-mail address: volkanediger@gmail.com (V.Ş. Ediger). http://dx.doi.org/10.1016/j.coal.2014.06.008 0166-5162/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect International Journal of Coal Geology journal homepage: www.elsevier.com/locate/ijcoalgeo