Geothermal development in Tanzania - status report

Abstract

Tanzania is among East African countries that are traversed by the East African Rift System. The geological settings for the occurrences of geothermal resources in Tanzania are variable and include potentials that are likely to be associated with typical young volcanic provinces in the north, intersection of eastern and western arms (triple junction) in the south west, faulted granite areas in central Tanzania (craton), and intrusives in young coastal sedimentary formations. This makes the occurrence of geothermal resources in Tanzania quite different from other countries. In addition the eastern arm and western arms tend to have different geological conditions that need to be differently considered during the exploration of geothermal energy resources in Tanzania. Tanzania’s power system has for decades relied on hydro and oil based generation mix. As a result, the power supply has been prone to variability and uncertainty due to frequent drought spells and oil price fluctuations. As a short term remedy, the government has resorted to emergency fuel oil based power plants to bridge the supply gap. This solution is not only expensive but also environmentally unfriendly. Tanzania’s aspirations to reach the middle income status as enshrined in the country’s Vision 2025 need to support the energy sector to access its agriculture and industrialization potential, and targets. Knowing that energy is vital for economic, social, and human development, Tanzania has determined to develop a sustainable energy mix that will ensure that households, communities, businesses and industries receive supply that is adequate, available when needed, reliable, convenient, healthy and safe for supporting the county’s development agenda.

The country’s current total grid installed capacity is 1,435.56 MW. This is from hydro 567.7 MW, natural gas 782.82 MW, liquid fuel 70.54 and biomass 10.5 MW. Previously, the national power system mostly relied on hydropower. Long and frequent periods of drought, which may have been caused by climate change, between 2003 and 2006, 2009 and 2010 led to shortfalls in electricity supply from the hydropower stations. Thus, the government of Tanzania resorted to thermal based generation sources as a short term solution. As a long term power development strategy the government intends to diversify the country’s energy generation mix and is focusing on increasing the proportion of renewable energy generation, whereby geothermal development is ranked high on the list. Other renewable sources being considered are wind and solar. Geothermal resource studies in Tanzania date back to 1949 but have been limited to surface studies mainly, measurements of surface temperature, water and gas sampling and analyses of hot springs. To date, drilling exploration wells program is planned for Ngosi geothermal prospect, with the consultant on site. Songwe, Kiejo-Mbaka and Luhoi geothermal fields rank next to Ngosi. The detailed surface study supported by ICEIDA/MFA was completed for Kiejo-Mbaka and Luhoi propects by year 2017. Additional scientific study in Songwe has been undertaken with the support of EAGER consultants. This paper presents the progress of geothermal development and lessons learned since year 2018 when the last Tanzania status report on geothermal development update was presented. It also presents some important results of the surface exploration studies, geothermal development strategies, mobilization of funds, investiment opportunities and development of local capacity to implement geothermal projects in Tanzania