Small-Scale Rural Electrification and Direct Use of Low-Temperature Geothermal Resources at Mbaka Fault in SW Tanzania

Abstract

The objective of the paper is to present first evidence for suitability of Mbaka faultfs low-temperature geothermal systems for rural electrification projects.

The Karonga basin north of Lake Nyasa in the southwestern part of Tanzania is characterized by the prominent NW-SE trending Livingstone border fault and the parallel major intra-basin Mbaka fault. Several hot springs emanate along the highly permeable Mbaka fault with temperatures of up to 70‹C, flow rates of up to 20-40 l/s and partly artesian outflow. Three license areas are currently under geological, hydrological and geochemical exploration by Geothermal Power Tanzania Limited and include both Mbaka and Livingstone faults. Fluid geothermometric results indicate anticipated temperatures of the deep reservoir(s) of .160‹C. The recharge area of the Mbaka hot springs is located mainly in the elevated region of Kiejo volcano N to NE of the hot springs and is characterized by humid climate.

A first conclusive conceptual model is presented for the southernmost Kilambo prospect at Mbaka fault as basis for identification of sites for drilling of exploration wells and planning of well paths. After successful drilling of a more than 600m deep exploration well and a shallower injection well, a wellhead generator will be used for early power generation. In addition direct heat utilization will be considered mainly for use in drying of agricultural products by constant and reliable conditions to enhance the quality of the products (e.g. tea leaves) or to avoid wastage of rotten fruits (e.g. bananas). The presented rural electrification concept will be applied in several sites at the Mbaka and Livingstone faults if on-going exploration will show promising results.

The paper gives an overview on previously existing data and the new findings for geothermal development at Mbaka and possibly also Livingstone faults.