Geothermal Direct Application and its Development in Tunisia

Abstract

In Tunisia, the use of geothermal energy is limited to direct application because of the low enthalpy resources, which are localized mainly in the southern part of the country. For thousands of years, geothermal water has been used in bathing, and many of the geothermal manifestations in the country have the name of ‘‘Hammam’’ or bath, which reflects the main use of geothermal water over the centuries. Now, most of the resources are utilized for irrigation of oases and heating greenhouses. The government’s policy in the beginning of 1980’s was oriented toward the development of the oasis sector, which is supplied with geothermal water for irrigation. Therefore, about 80 boreholes are operating mostly to complete the irrigation of 31,500 ha of oases after cooling the water in atmospheric cooling towers. Generally, when the water temperature is less than 40-45°C, it is used directly for irrigation.
In 1986, the government started using geothermal energy for greenhouse farming, which is considered a promising and economically feasible application, by planting one ha in the southern part of the country (Kebili area). The results of this experiment were encouraging, and thus the cultivated areas have today increased to 194 ha. The utilization of geothermal resources is increasing very fast showing a real boom in greenhouses areas. Nowadays, heating greenhouses in southern parts of Tunisia are considered as the only experience in the world in terms of development in this field in the difficult desert conditions. By the end of 2016, the objectives certainly will be crossed, reaching 315 ha.