With the unreliable power grid and rising electricity costs, mining companies and other intensive electricity users should explore alternative energy sources such as renewables. South Africa is among the world’s biggest emitters of carbon dioxide because of its heavy reliance on coal as a primary energy source, which currently accounts for 71% of the total energy mix.
To substantially reduce the pollution levels in the country, which experts have warned pose a serious health risk; the country is seriously looking at adopting renewable energy instead of its dependency on fossil fuel.
Recently, a team representing a number of universities and science councils advised the mining sector to adopt alternative self-generation technologies to diversify their energy supply. The group was commissioned by the Mandela Mining Project to develop energy efficiency guidelines for the industry, through directed research and development.
The Mandela Mining Precinct is a public-private partnership between the Department of Science and Innovation and the Minerals Council South Africa. It is managed and hosted by the CSIR. Its primary objective is to revitalise mining research, develop and innovate it to make sure the industry is sustainable.
Martin Pretorius, the precinct’s programme manager, recently told a virtual workshop that: “Through this research theme, we are investigating current systems in the industry, with the aim to structure alternative energy sources and optimise energy supply strategies, and efficient energy utilisation.”
Pretorius is responsible for the Mechanised Mining Systems research programme, which focuses on developing solutions that will lead to the increase of economically feasible platinum and gold ore bodies through new approaches.
University of Pretoria’s senior lecturer in the Centre for New Energy Systems, Dr. Xianming Ye is one of the research theme leaders. He reckons that the study should focus on both the financial and technical viability of renewable energy options available to the industry.
Dr Peter Klein, another expert involved in the initiative, said that since 2008 the country has been experiencing increasing high electricity costs, which many mining houses struggled to absorb. Dr Klein, who is also a CSIR senior researcher said: “The 2019 Integrated Resource Plan indicates that the cost of electricity will continue to increase in real terms up to 2050, as the aging coal fleet is replaced with new generation capacity.”
Klein said the rising grid electricity prices will lead to a progressive decline in the costs of renewables such as wind and solar photovoltaics (PV), adding this will open new opportunities for industrial users to consider “embedded generation”.
He said the roll out of a customer response at scale can also lead to significant reduction of the levels of load shedding. But he cautioned that the cost of going off the grid is currently prohibitive, and that an ideal solution will likely include a mix of grid electricity, supplemented with embedded generation.
Recent climate modelling shows that the gold and platinum mining regions of South Africa are situated in good solar source. Klein said there were three primary options available to utilising the solar source:
- Electricity can be generated using PV technologies
- concentrated solar power (CSP), which converts solar energy into heat using concentrating collectors to drive a steam turbine and produce electricity and the third option is
- the use of solar thermal systems to generate heat for industrial process heating.
Regarding wind as a source of energy, Dr Klein indicated that the identified mining regions have poor wind resource. However, he said, there is a good wind resource in an area of the North-West, which is within a 100 km proximity to many mines.
He explained that a mix of solar and wind provides the least cost mix of electricity due to the complementary nature of the solar and wind sources, and decreasing costs of these technologies. These energy sources can be supplemented with gas, biomass, CSP, demand-side management, and energy storage, he added.
According to the South African Weather Service researcher, Dr Henerica Tazvinga, by 2030, the energy mix would likely look very different, with coal expected to represent only 43%. It will be followed by wind, which will increase from the current 4% of the energy mix to 23% by 2030.
It is anticipated that the framework and guideline generated through this study, will gain traction and attract industry support and uptake, said Pretorius.