Geothermal energy is produced by natural heat emitted by lava inside the earth. This energy is concentrated around contemporary volcanoes and the world earthquake belt
Warm water springs and geysers, which are plentiful around volcanoes and the active regions of the earth, are clear examples of geothermal energy. Geothermal energy has been used for the production of energy in the world since the beginning of the 20th century. Today 22 countries use geothermal energy to produce more than 6000 MW of electricity and 80 countries use this energy to produce 12000 MW of heat energy. The main producers are Unites States, Italy, the Philippines, Mexico, Indonesia and Japan. Geographically, Iran is situated on the geothermal energy belt. Clear examples of the existence of this energy can be found near the Sabalan, Sahand, Damavand, Taftan and Bozman volcanoes.
The discovery of geothermal energy in Iran dates back to 1971. In 1975, the Iranian Energy Ministry signed a contract with the National Italian Electricity Company in order to start studies and research on geothermal energy in Iran. Initial studies showed that the four regions of Sabalan, Damavand, Maku – Khoy and Sahand, which covered a total area of 31000 square kilometres, were the best regions to conduct detailed studies and exploration. As a result, geographical and physical exploration took place in the mentioned regions and the underground waters were identified. Then a final report was presented to the Energy Ministry in 1982. These reports were studied and analysed by UN geothermal experts in 1990. In line with this, since 1992, the Energy Research Centre has studied and analysed all expert reports and comments in order to finalize explorations and to acquire geothermal energy in Iran. This centre reached the conclusion that the Meshkin Shahr region in Sabalan would be the priority for the completion of explorations and the construction of a geothermal power plant, and it drew up its final proposals in that regard. This paper is a summary of the results of the studies and exploration work carried out in Azerbaijan and Damavand.

Sabalan Region
Sabalan is situated to the west of the city of Ardabil between the cities of Ahar, in the northwest, Mehraban, in the southwest, Sarab, in the south and Vakilabad in the southeast The peak the of inactive Sabalan volcano, with a height of 4800 metres above sea level, is always covered in snow. Due to precipitation and the melting of snow, warm water lakes have formed on the peak and around the Sabalan Mountain. The water extracted from existing cracks continuously feeds the shallow and deep water expanses. The underground water expanses are situated beside the rich heat resources deep in the earth and make up the geothermal reservoirs. The existence of the various warm water springs such as Qinrache, Moil, Shahabil, Quturusui, Ilando, Maleksu, Borjelo, Viladareh, Sarein, Ilanjaq, Saqzchi and …, which can reach a temperature of 25-83 degrees Celsius, are evidence of the existence of rich geothermal energy resources in the Sabalan region.
The Sabalan region consists of the three geothermal regions of Meshkin Shahr, Barjlu, and Sarein. There are various warm water springs in these three regions. The warmest are Meshkin Shahr’s Qinrache, with a temperature of 83 degrees Celsius, and Borjelo, with a temperature of 77 degrees Celsius. Most of Sabalan region’s springs are situated on fault lines or cracks. The maximum discharge rate of Sabalan region’s warm springs is 9000 litres per minute and they are situated in Meshkin Shahr. In line with the activities of the Energy Research Centre, geological operations were carried out in the Meshkin Shahr geothermal region in 1996-1997 and the geological status of Sabalan has been determined to a depth of more than three kilometres. Based on this, the carbonate permeable of the Elika and Tizkuh (from the Cretaceous era) which has a high permeable, form the stones of geothermal energy reservoirs. The low-permeable articeles in Shemshak (from the Jurassic era) and Karaj cover the reservoir rocks.
According to analysis of the results of the gravimetric operations in Sabalan region, there is a widespread and extensive region between Meshkin Shahr and Ahar which contains low-density sediments with high porosity which create suitable reservoirs in this region. They are called the Ahar-Meshkin Shahr-Lahrud sedimentary zone.
According to chemical thermographic studies, the average temperature of the geothermal reservoirs in Meshkin Shahr and Borjlu and Sarein regions are 240 and 140 degrees Celsius. In addition, a comparison of the boron-chlorine density in the warm waters of Meshkin Shahr, Borjlu, and Sarein, show that these three regions which are in Sabalan, have the same heat source. According to available information and experts, the heat potential in the Sabalan region’s geothermal reservoir can reach 48x10*15 kilojoules and it has the potential to produce 100 MW of electricity.

Damavand Region
The Damavand region is situated to the northeast of Tehran (Diagram 3). At the centre of this region, there is a young volcano with a height of 5670 metres. Damavand contains an old volcanic opening which still releases volcanic gases and steam. Other evidence of this region’s volcanic characteristics is the existence of warm water springs such as Larijan, Ask and Bayjan, which reach a temperature of 28-60 degrees Celsius. Geological and thermographic explorations have been carried out in this region and the surface and underground waters have been identified.

Reporter : mehdi akbarsefat

َApproved by : Story Id 28

Create date : 19 Feb 2008 14:43

Id : 2119

Email	Get topic file	Print edition