Geothermal potential in East Africa - how to realise it

Abstract

The East Africa Rift System is an example of a continental rift system associated with the world-wide mid ocean rift systems. It is divided into two rift systems; the Eastern and Western branch. The Eastern branch straddles southwards from Afar triple junction through Ethiopian highlands, Kenya, Tanzania and Malawi to Beira, Mozambique in the south. The western branch transects through Uganda, DRC and Rwanda while the nascent south-western branch runs through Luangwa and Kariba rifts in Zambia into Botswana. The volcanic and tectonic activity in the rift started about 30-45 Ma ago and in the eastern branch the activity involved faulting and eruption of large volumes of mafic and silicic lavas and pyroclastics. The western branch, typified by paucity of volcanism, is younger (12 Ma) and dominated by faulting that has created deep basins currently filled with lakes and sediments. Geothermal activity in the rift is manifested by the occurrences of Quaternary volcanoes, hotsprings, fumaroles, boiling pools, hot and steaming grounds, geysers and sulphur deposits. The manifestations are abundant and stronger in the eastern branch that encompasses Afar, Ethiopian and Kenya rifts while in the western branch, the activity is subdued and occurs largely as hotsprings and fumaroles. Detailed studies of geothermal potential in Eastern Africa indicate that the region has potential > 10,000 MWe. Geothermal exploration in East Africa began in 1952 in Kenya, 1969 in Ethiopia, early 1970’s for Uganda and 1949 for Tanzania.

The estimated geothermal potential in the East Africa Rifts system is over 10,000 MW. Currently, Kenya is at an advanced stage of geothermal development with the generation of about 692 MWe. On the other hand, Ethiopia has an installed capacity of 7.28 MWe, while Tanzania, Uganda, Eritrea, Rwanda, Zambia, Malawi, and Djibouti are still either in exploration or drilling stage. To accelerate and realise the full geothermal potential of the East Africa region, there is no doubt that adequate measures need to be put in place by the respective governments