Countries within the East African Rift System (EARS) have as much as 20GW of potential electricity generation available through geothermal sources, but several challenges have seen only about 5% of this being harnessed.
The African Continental Power Systems Masterplan (CMP) study into Geothermal Power Plants (GPP) says geothermal power offers multiple benefits including high capacity factors and low costs.
The masterplan is being developed by the African Union Development Agency (AUDA-NEPAD) with the EU-GTAF, IRENA and IAEA.
Despite geothermal power’s potential, the AUDA-NEPAD study says the initial development of these projects “presents considerable challenges and risks both in terms of resource exploration and fundraising.”
“The high costs of drilling exploration with no guarantee of the estimated potential during the surface exploration phase discourages many private investors and developers.”
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The EARS countries consist of an eastern branch and western branch. The eastern branch extends from the main Ethiopian Rift (Djibouti, Ethiopia and Eritrea) through Kenya into northern Tanzania.
The western branch extends from northern Uganda through Rwanda, DRC, Burundi, southern Tanzania, Malawi, Zambia, and Mozambique.
Geothermal exploration in East Africa
The study notes that Kenya is the most advanced in its geothermal exploration, having grown its installed capacity from 15MW to 950MW and actively pursuing an increase to 10GW by 2040.
Ethiopia has recently initiated efforts to develop large GPP, with investment in drilling campaigns in several geothermal fields to confirm their potential.
Djibouti, Tanzania and Zambia are taking their first steps by undertaking surface evaluations and sinking exploration wells to estimate the potential.
The DRC and Eritrea are still to consider and develop conducive policy.
“Ultimately, reducing some of the upfront project risk is a pre-condition to attracting the private investment needed to unlock these opportunities,” the study says.
The CMP being developed for Africa shows geothermal power to grow from 0.7% in 2023 to 1.1% of the electricity mix planned for 2040.
“Current planning for the future diversified energy mix supports the expansion of geothermal power plants (GPP) to countries with a high potential, but with little to no existing generation.”
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How is it stored and used?
Geothermal is a type of renewable energy taken from the earth’s core. It comes from heat generated during the original formation of the planet and the radioactive decay of materials.
This thermal energy is stored in rocks and fluids in the centre of the earth.
“The difference between the temperature in the earth’s core and its surface drives a continuous conduction of thermal energy from the interior to the exterior, where the rock and water in the earth’s crust can reach temperatures as high as 370°C.”
The thermal energy contained in these rocks and fluids can be found from shallow depths right down to several miles below the earth’s surface.
“With technological advances, this almost inexhaustible source of energy, was first used to produce electricity in 1904 and the global installed capacity reached 16GW in 2021.
“Geothermal energy is also used directly, by piping thermal water for heating greenhouses, fish farms, and municipal heating systems. Geothermal heat pumps can be installed almost anywhere and are widely considered the best way of heating and cooling homes.”
The study says the systems with the greatest potential for energy production are in areas where the geothermal gradient is higher than average (30ºC/km).
“These systems are scattered along the plate boundaries where the thermal anomaly is felt with greater intensity and at a shallower depth in Africa GPPs would be situated on the EARS.
“Here, a distinction must be made between the countries with the greatest GPP potential, located on the boundaries of tectonic plates where the heat source is closer to the surface, the eastern branch of the EARS: Ethiopia, Eritrea, Djibouti, Kenya, Somalia and Tanzania (north).
“Countries located on the western branch – Burundi, Uganda, Rwanda, Tanzania (west), Malawi, Mozambique, Zambia and DRC are better suited for direct use projects.”
Pros and cons of geothermal energy uptake
Globally, the US has the biggest installed capacity (3.7GW), followed by Indonesia (2.3GW) and the Philippines (2.2GW).
Kenya and Italy are the seventh biggest at 0.95GW. The only other country in Africa with GPP capacity is Ethiopia with 8.5MW.
The DRC and Zambia have small historic GPP but neither are operational. It is estimated that east Africa has a total GPP potential of between 15GW and 20GW, the study says.
“Currently, the total installed capacity is 1GW making this a largely underexploited energy resource.
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“The high upfront costs and risk associated with GPP must be considered in the context that this technology competes with other power generation sources and technologies that may be cheaper, easier to deploy, offer higher certainty and flexibility.
“Thus, countries endowed with significant hydro and natural gas resources may not have a strong incentive to develop GPP despite the listed advantages of high-capacity factor, baseload supply and low operating expenses.”
But with over a third of its total capacity derived from geothermal, 328MW under construction and a stated target of up to 10GW by 2040 Kenya is not only an African, but a global leader, the study says.
“This is attributed to clear policy direction and taking actions which have reduced risks for private investors by establishing adequate and transparent legal, institutional, and regulatory frameworks.”
Find out more about the AUDA-NEPAD studies online.
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