With recent social and economic advances in South Africa comes an immense added pressure on the National Energy Grid, consequentially resulting in rolling power outages during the times of peak demand. Moreover, this has a direct effect on our economy, such as the case with the construction of a large ferrochrome smelter being moved from Rustenburg to China because continuous electricity could not be guaranteed. In an effort to combat these energy shortages and provide uninterrupted electricity supply to the country and large industries, Eskom has planned construction of two new power plants in Limpopo and Mpumalanga, as well as the recommissioning of three older stations, which will compound the Energy Grid and double it's capacity to 80,000 MW by 2026.
While these newer power plants are highly efficient at their usage of natural resources, there remains the ever present concern regarding climate change and carbon emissions. In addition, within the last decade South Africa has become the leading carbon emissive nation in Africa producing more than 430,000 kt of carbon dioxide emissions from burning nonrenewable energy sources, which amounts for 90% of South Africa's total energy production. Having agreed with the Kyoto Protocol and playing an active role in climate change and the global shift towards renewable energy that lead to the hosting of the COP17 climate change summit in Durban, which promises to provide concrete regulations not firmly constrained during previous summits, the South African Government launched the White Paper on Renewable Energy, 2004 which together with a renewable energy mandate in a National Environmental Act launched in 1999, aims to reduce carbon emissions by up to 34% by 2020 and moreover produce up to 10,000 GWh of renewable energy by 2013. This aim is on track to being realised with promising results shown in a solar heating pilot installation projects and compounded with plans to further hydro and wind generated forms of electricity.
In an effort to join this fight against climate change I've began investigating the prospect of harnessing geothermal energy within South Africa. Being placed on the Archean Kaapvaal Craton compounded by a very thick and dense mantle keel reaching depths of up to 250 km, which serves as the ideal location for the formation of some of the worlds best diamonds, but unfortunately does not provide the best target areas for geothermal energy which is further reduced with the lack of active volcanism. Previous research does however illustrate heat-flow signatures and the presence of anonymous high-heat flow and heat-producing regions within the Kaapvaal Craton, which may prove to be the ideal future locations for the successful extraction of geothermal energy. This form of geothermal energy, known as Enhanced Geothermal Systems, employs the use of exploiting a high geothermal gradient by pumping a working fluid down the gradient into a deep-seated reservoir where the water is heated to critical levels and thereafter runs up a production line and produces energy.
The energy producing capabilities of a successful geothermal plant of this nature in South Africa would have immense benefits with one plant having the equivalent energy output as 25 wind turbines and furthermore having the ability of exponentially decreasing carbon emissions with simultaneous sequestration. Being a new field, a great deal of further research is required to fully understand these possibilities, however if successful this could provide an ideal solution to South Africa's energy problems while substantially decreasing our carbon footprint.
