Agricultural Geothermal Energy Use In Tunisia

In Tunisia, the use of geothermal resources is limited to direct application because of the low enthalpy resources ranging from 30 to 80°C, which are localized mainly in the southern part of the country. Most of the resources are utilized for agriculture, especially in irrigation of oases and heating greenhouses. Because of the water scarcity in the southern part of the country, the geothermal water is used to complete the irrigation of oases after cooling it in atmospheric cooling towers. Therefore, about 80 boreholes are operating to complete the irrigation of 30,000 ha of oases. Generally, when the water temperature is less than 40-45°C, it is used directly for irrigation. Since 1986, the government started using geothermal energy for greenhouse farming, which is considered a promising sector, by planting 1 ha in the southern part of the country. The results of this experiment were encouraging, and thus the cultivated areas have increased to reach 240 ha exploited by 450 farmers. The agricultural uses of geothermal resources in southern parts of Tunisia are considered as the only experience in the world in terms of development and sustainability in this field. The prospective study for the year 2030, will certainly give a clear outlook of the greenhouse sector, reaching an area of 350 ha.