South Africa: The Case for Geothermal Energy

Should SA tap geothermal energy?

Geothermal technology is expensive, but it should still be part of South Africa’s energy mix.

South Africa, the leading carbon emitter in Africa, has geothermal resources that can be used to generate electricity and reduce its carbon emissions. But a recent study suggests that the potential cost is prohibitive, unless strong incentives are provided.

Geothermal is omitted from this mix. Unlike many renewables, geothermal is stable and can be used as part of the baseload electricity supply. It may also provide an effective long-term energy source with minimal waste.

South Africa does not have any active volcanism and is mostly underlain by a very thick upper crust. This is unlike East African countries — for example Kenya and Ethiopia, where the upper crust is ever expanding and remains thin. This allows heat from the mantle to penetrate close to the surface. Drilling for these geothermal sources is shallow (> 3km) and therefore inexpensive.

The lack of volcanism, thick upper crust and a deep mantle keel created a common misconception that South Africa is devoid of geothermal potential.

There are, however, anonymously hotter regions. These regions have thinner crust, vast amounts of heat-producing igneous rocks and numerous hot springs. But harnessing geothermal in South Africa assumes drilling of up to 5km, which is very expensive.

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