Geothermal Resource Assessment for Mt. Longonot, Central Rift Valley, Kenya

Abstract

Africa Geothermal International Ltd (AGIL), with the assistance of Sinclair Knight Merz (SKM), is evaluating the potential development of the Longonot geothermal system located in the Kenya Rift Valley northwest of Nairobi and 10 km east of the Olkaria Domes geothermal field. Mt Longonot, a trachytic stratovolcano southeast of Lake Naivasha, is in an area of active west-to-east extension (the Rift Valley) as well as an area of crustal uplift and thinning (the Kenya Dome). Results obtained during a comprehensive geological, geochemical and geophysical field program in 2010 have been used to develop a conceptual model of this high-temperature system. The estimated power plant capacity within the area with the highest estimated power density is about 150 MWe, which is sufficient to service the project target capacity of 140 MWe. A phased drilling program is proposed to prove, delineate and develop the resource.