South Africans have been experiencing up to 10 hours of load-shedding per day, and maintenance on Eskom coal plants is being delayed due to “skills and liquidity challenges”. Meanwhile, the Eskom gas power plants in the Cape, and the private Avon and Dedisa gas power plants, are running up billions in fuel and operating costs. Sometimes the diesel fuel logistics cannot keep up.
Koeberg appears to be hurtling towards disaster, with a dropped reactor, an expiring nuclear operating licence and delayed maintenance and upgrades, compounded by an exodus of key technical and managerial skills. When both Koeberg units are offline, transmission losses to the Cape amount to an entire unit of a typical Eskom “six-pack” power station, about 500MW.
The energy crisis seems hopeless and our national leadership even more so. But SA’s energy problems are fixable, and in a shorter time than many believe. In fact, with the correct interventions the country could soon be exporting excess electricity to its neighbours:
- Install rooftop solar photovoltaic (PV) and battery energy storage systems at every structurally sound industrial, commercial, educational, medical and residential structure in the country;
- Install utility-scale solar PV generation together with batteries around the country, even in areas with less attractive solar irradiation levels — but only where transmission and distribution capacity is available. This will provide geographical diversity for natural weather patterns, dispersion of generation closer to load centres, and resilience for extreme weather events;
- Construct strategic transmission lines in the Northern Cape and adequately compensate landowners for transmission line servitudes and power lines on their properties. This would unlock an immediate 5GW-10GW of shovel-ready utility-scale independent power producer (IPP) solar PV projects; and
- Contract floating storage regasification units (FSRUs) and construct 1GW open cycle gas turbines in conjunction with these FSRUs at coastal cities such as Richards Bay, East London, Gqeberha and Saldanha Bay.
According to the SA Housing Market Report there were about 17-million households in SA in 2020. If a 5kW PV system were to be installed on just one 20th of these structures it would amount to 4.2GW. That is the generation capacity of a large Eskom coal-fired “six-pack” power station, and more than twice the capacity of Koeberg.
Due to the diurnal characteristic of the sun as well as clouds and rain, this would not provide around-the-clock energy, but it would be an important addition to energy supply and could be significantly improved by adding batteries, to be charged when the sun shines, and discharged at night. Add to the above 4.2GW capacity from office blocks, commercial buildings, schools, factories, hospitals, warehouses and millions of carports and car parking areas, and the potential capacity from solar PV is significantly larger.
Legislation is urgently required to allow consumers to become prosumers — consumers who can also export their power to the grid and be compensated for it, albeit at differential tariffs. Time of use tariffs could be implemented to encourage better electricity use behaviour. Tax incentives and financial models from large financial institutions should be accelerated to assist customers who would find the capital outlay for solar PV and battery storage systems prohibitive. Rooftop PV and batteries can be installed within weeks.
Over the past decade, as a result of the Renewable Independent Power Producer Programme, variable renewable energy (VRE) developers (solar PV and wind developers) have been identifying sites with the best solar irradiation and wind resources. However, transmission line capacity is diminishing, and in the Northern Cape close to Upington transmission capacity is used up.
VRE independent power producers (IPP) should be encouraged to install geographically dispersed plants, close to transmission and distribution infrastructure and load centres. This would decrease electricity transport losses, provide geographical diversity to compensate for natural weather patterns and resilience for extreme weather events. Utility-scale VRE power plants and battery systems can be installed within a year.
There are only two 400kV transmission lines from Aries substation in the Northern Cape (near Upington) to the key load centres of Gauteng, the Free State, KwaZulu-Natal and the Northern Province. Each 400kV line can transport roughly 500MW (0.5GW). There is an estimated 5GW-10GW of planned and shovel-ready utility-scale IPP solar PV projects in the Northern Cape, where the solar irradiation levels are the best in the country. However, this capacity cannot be connected to the transmission system as the lines from the Upington area are already running at full capacity.
Additional transmission lines out of the Upington area have already been planned and designed, but servitudes/wayleaves cannot be obtained from landowners on the routes of the 400kV transmission lines. Servitudes for these transmission lines need to be secured for the national good, and some mechanism of fair compensation needs to be offered to landowners to secure them. It is possible to build 400kV lines in two years with the correct procedures in place.
As the penetration of inverter-based variable renewable generation increases, the need for mitigating flexible power plants also increases to counteract the intermittency and variability of the renewable energy. System flexibility can be obtained from batteries, but another important source of flexibility comes from open-cycle gas turbines and diesel engines. Flexible thermal power plants also provide fault level and system inertia, and they can be called upon during extended bad weather periods or as backup generation when other conventional synchronous generation has unplanned and planned outages.
The capital cost of gas and diesel turbines is low, though the fuel costs are high. However, with the correct planning and operation these thermal power plants should not operate for extended periods — no more than 5% of a calendar year, which is an environmentally acceptable compromise. Liquefied natural gas prices are now high due to the war in Ukraine, but when the war ends they should return to normal levels. Natural gas and diesel generators can be constructed in under two years if the necessary authorisations are in place.
Large natural gas volumes exist in the north of Mozambique (estimated at 100-trillion cubic feet). If gas pipelines could be built similar to the Sasol Temane pipeline natural gas thermal power plants could be built at nonport sites in SA. A Mozambique north-south transmission system should be constructed to unlock the 1,200MW Cahora Bassa North Bank hydro generation capacity and the 1,500MW Mphanda Nkuwa hydropower project on the Zambezi River.
The large 40GW Grand Inga hydro power plant on the Congo River in the Democratic Republic of Congo should be expedited together with the long and extremely high voltage (EHV) AC and DC transmission infrastructure to transport this clean energy to SA and the rest of Africa. In addition, transmission interconnectors between Tanzania and Zambia/Malawi should be expedited to access large quantities of low-cost hydro power from sources such as the 6GW Grand Ethiopian Renaissance hydropower plant on the Nile River.
The above interventions will not provide an immediate remedy to SA’s power woes, but they can provide an environmentally friendly, best-cost, reliable and technically achievable direction for the energy sector in the short, medium and long term.
• Tuson is an electrical engineer with more than 30 years’ experience in the power industry in SA, Africa and globally, who specialises in planning and designing power systems to incorporate reliable, renewable, climate-resilient and best-cost energy solutions.