Geothermal district heating applications in Turkey: a case study of Izmir-Balcova

Turkey is located on the Mediterranean sector of the Alpine-Himalayan Tectonic Belt and is among the first seven countries in abundance of geothermal resources around the world. However, the share of its potential used is only about 2%. This means that considerable studies on geothermal energy could be conducted in order to increase the energy supply and to reduce atmospheric pollution in Turkey. The main objective in doing the present study is twofold, namely: (a) to overview the status and future aspects of geothermal district heating applications in Turkey and (b) to present the Izmir-Balcova geothermal district heating system, which is one example of the high temperature district heating applications in Turkey. The first geothermal heating application was applied in 1981 to the Izmir-Balcova thermal facilities, where the downhole heat exchanger was also used for the first time. Besides this, the first city based geothermal district heating system has been operated in Balikesir-Gonen since 1987. Recently, the total installed capacity has reached 820 MWt for direct use. An annual average growth of 23% of the residences connected to geothermal district heating systems has been achieved since 1983 in the country, representing a decrease of 5% in the last three years. Present applications have shown that in Turkey, geothermal energy is much cheaper than the other energy sources, like fossil fuels, and can make a significant contribution towards reducing the emission of greenhouse gases. (C) 2002 Elsevier Science Ltd. All rights reserved.