29 October 2014
Exploration for Sedimentary Basin Hosted Low-Enthalpy Geothermal Systems in Zambia
Vivian-Neal P F R
Kalahari GeoEnergy Ltd
PostNet268, P/Bag E017, Crossroads, Lusaka, Zambia
Email Address email@example.com
Published in the Proceedings of the 5th African Rift Geothermal Conference, Arusha, Tanzania, 29-31 October 2014
Keywords: Geothermal, Sedimentary Basin, Kafue Trough, Exploration
While there has been historic work in Zambia relating to geothermal energy, including the building of a pilot power plant on the Lake Tanganyika fault, there was no economic imperative to follow-up due to an abundance of low cost large scale hydroelectric power. In response to the changing dynamics that the new hydroelectric power is no-longer low cost and the challenge of meeting escalating domestic and industrial/mining demand, alternative sustainable energy has become a priority both in Zambia and Africa generally.
Sedimentary basins which occur in regions of active extensional tectonics provide a geological setting conducive to geothermal systems. The Karoo era basins within Zambia which have regionally extensive normal faults are now being found to contain geothermal systems that justify exploration.
As a private company operating within defined permit timelines and with an elective right to target development, a range of exploration techniques are being undertaken to define those most effective in identifying preliminary drill targets at one specific site within the Kafue Trough. These include ground magnetics, radiometric, gravity, resistivity, geo-botany and soil temperature profiles. From this work a preliminary drill programme confirmed the presence of a hydrothermal system produced from >150OC up-flow along deep faults in the Proterozoic basement, with outflow along shallow permeable zones within the basin fill. The system is overlain by Karoo sediments forming the thermal cap rock. Exploration work is ongoing and further drilling is planned; the objective is to commence a pre-feasibility study in the next year. The system model and most effective exploration techniques are being rolled out to other targets within the sedimentary Basin. Meanwhile research suggests direct applications of geothermal energy could play important roles in rural energy, industrialisation and food security programmes; a Community Investment Programme is trialling water filtration to produce potable water in response to the Millennium Challenge.
The full pdf file is available here.