An evaluation for harnessing low-enthalpy geothermal energy in the Limpopo Province, South Africa

Abstract

South Africa generates most of its energy requirements from coal, and is now the leading carbon emitter in
 Africa, and has one of the highest rates of emissions of all nations in the world. In an attempt to decrease its
 CO
 2
 emissions, South Africa continues to research and develop alternative forms of energy, expand on the
 development of nuclear and has began to explore potentially vast shale gas reserves. In this mix, geothermal
 has not been considered to date as an alternative energy source. This omission appears to stem largely
 from the popular belief that South Africa is tectonically too stable. In this study, we investigated low-enthalpy
 geothermal energy from one of a number of anomalously elevated heat flow regions in South Africa. Here, we
 consider a 75-MW enhanced geothermal systems plant in the Limpopo Province, sustainable over a 30-year
 period. All parameters were inculcated within a levelised cost of electricity model that calculates the single
 unit cost of electricity and tests its viability and potential impact toward South Africa’s future energy security
 and CO
 2
 reduction. The cost of electricity produced is estimated at 14 USc/KWh, almost double that of
 coal-generated energy. However, a USD25/MWh renewable energy tax incentive has the potential of making
 enhanced geothermal systems comparable with other renewable energy sources. It also has the potential
 of CO
 2
 mitigation by up to 1.5 gCO
 2
 /KWh. Considering the aggressive nature of the global climate change
 combat and South Africa’s need for a larger renewable energy base, low-enthalpy geothermal energy could
 potentially form another energy option in South Africa’s alternative energy basket.