| Abstract |
Mozambique is located on the southeastern coast of Africa and borders with Zambia, Malawi, Tanzania, Zimbabwe, Swaziland and South Africa. The economy of Mozambique is mainly dependent on agriculture, that constitutes 21% of gross domestic product (GDP) and the bulk of merchandise exports. Mozambique suffers for the improper utilization of natural resources and the sustainable access to energy is extremely low. This situation is partly due to the high cost of extending networks and increasing the number of connections in remote and relatively low demand area using conventional technologies and design standards. At present only 13.2% of the population has access to electricity and where it is available, it is supplied by diesel generators. Energy solutions must take this reality into consideration and adapt to it by combining an intensification of electrification in those areas served by the national electricity grid with the adoption of hybrid solutions, in particular for remote areas, using available and sustainable resources as the geothermics. In this framework, the development of the geothermal energy both in direct and indirect uses can represent an important goal even if, presently, it is totally unused. At present there are not ongoing geothermal exploration and exploitation projects in Mozambique for low and medium-high temperature. Government and international experts are only just beginning to study geothermal resources in Mozambique. A preliminary evaluation of local geothermal potential in unexplored areas was completed by McNitt (1978) and it was evaluated at 25 MWe. The most promising areas are the northern and central provinces of Mozambique, especially within the East Africa Rift just north of Metangula, where heat-flow values range between 70 and 170 mW/m2. Others interesting areas are along and to the west of major faults in the Espungabera-Manica areas, near the border with Zambia and Zimbabwe. The present work proposes a review on available data about thermal waters, including new data collected. A first geochemical survey was carried out in the Northern Mozambique in March-April 2013, with the aim to investigate chemistry and origin of some thermal springs in the Tete Province. The investigated area is located in the East African Rift, adjacent to the marginal sedimentary Mozambique Basin. This area is crossed by the Rio Zambezi, one of the main river in Africa and explored during the 19th century by Davi Livingstone. Many thermal springs are present in this province due to the proximity with the rift, but considerably little geochemical and geothermal studies have been done, due to the difficulties related both to the site accessibility and social interaction with local tribes. Three thermal springs were sampled close to the Missao de Boroma, Tete, crossing the Rio Zambezi by a traditional pirogue. Collected samples are being analysed to determinate major, minor and trace elements, δ18O and δD, dissolved gas, carbon isotopic ratios of TDIC (Total Dissolved Inorganic Carbon) (expressed as δ13C‰vs. VPDB), 3He/4He and dissolved Radon. The measured temperature ranges between 42°C to 66°C and pH from 7.9 to 8. The conductivity is around 2400 μS/cm and the Eh is between -208 to -404 mV. The chemical and isotopical analysis are in progress, anyway this first sampling suggests the need to plan and perform a national geochemical survey of the thermal springs in Mozambique. Data should be organized in organic geodatabase and geographic information systems. This information could have a big relevance not only for the geochemical, hydrogeological and geological knowledge of the Country but especially for an evaluation of the geothermal potential of Mozambique. Reference Mc Nitt J.R. (1978) – The United Nations approach to geothermal resource assessment. Geothermics, 7, 231-242. |