South Africa’s energy mix is diversifying, with renewables now making up 25% of the country’s total installed generation capacity. The north-western region of the country is endowed with vast tracks of land where sunshine is abundant and intense, particularly in the Northern Cape. This has attracted several independent power producers (IPPs) into the region.
The general idea in solar farming is to collect energy from sunlight and convert it into electricity, but the details of how this is done vary depending on which technology is employed. In the South African context, two types of solar farming technologies dominate in the renewable energy sector: photovoltaic (PV) panels and concentrated solar power.
PV panels are made up of layers of silicon which absorb photons from sunlight and release electrons that generate an electric current. Although PV systems have the advantage that they can scale from small residential installations to utility-scale plants that cover vast tracks of land, the power generated from PV cells generally has to be used or fed into the grid immediately as the cost of storage for this technology remains prohibitively high – for now.
Read: 10 biggest wind energy projects in South Africa
In contrast, concentrated solar power (CSP) farms use mirrors to focus sunlight onto a single point and can store the energy they produce in thermal systems for use at a later stage. CSP farms are only viable in areas with high direct normal irradiation – a measure of the intensity of sunlight – such as the arid regions of the Northern Cape. CSP solar farms that use thermal energy storage systems are also referred to as thermo-solar power plants.
TechCentral conducted desktop research into the largest, utility-scale solar power projects that feed energy into South Africa’s grid as part of government’s renewable IPP programme. These are the 10 largest solar farms, based on installed capacity, in South Africa…
1. Xina Solar One | Concentrated solar power
Spread over 850 000sq m near Pofadder in the Northern Cape, this 100MW thermo-solar power plant is the biggest solar power complex in Africa when combined with the adjacent Kaxu Solar One solar power plant mentioned further down the list.
The Xina Solar One plant makes use of cylindrical-parabolic collectors and a thermal storage system to generate electricity. The parabolic concentrators are made of curved mirrors that track the sun and concentrate solar energy onto synthetic oil-filled absorber pipes.
The oil in the pipes is heated to 395°C and transferred to a heat exchanger. The exchanger then heats water to generate steam, which turns the turbine and generates electricity.
The heat from the oil is also used to heat 47 000t of molten salt stored in thermal energy storage tanks. This system can generate electricity for up to five hours after sunset.
2. Karoshoek Solar One | Concentrated solar power
Karoshoek Solar One, also referred to as the “Ilanga” project, is a 100MW CSP plant 30km east of Upington in the Northern Cape. Karashoek also makes use of arrays of curved cylindrical panels, known as parabolic troughs, to concentrate sunlight into a receiver tube that is filled with a heat transfer fluid. The heat transfer fluid heats water into steam, which turns a turbine and generates electricity.
Karoshoek went live in November 2018 and is expected to feed the national grid for the next 20 years or more.
3. Khatu Solar Park | Concentrated solar power
Kathu Solar Park is named after the Khatu region of the Northern Cape in which the 100MW CSP plant is situated. Operations on this site commenced in January 2019 using parabolic trough technology and a molten storage system that can produce electricity for 4.5 hours after the sun has set.
According to the project website, Khatu will displace six million tons of carbon dioxide over its initial 20-year lifespan.
4. Kaxu Solar One | Concentrated solar power
Kaxu Solar One is a 100MW thermos solar plant located in the same complex as the Xina Solar One plant in Pofadder. When combined, the two plants make up the largest solar power complex in Africa. Kaxu’s molten salt storage system has the capacity to generate electricity for 2.5 hours without sunshine. The parabolic trough collectors used at Kaxu are 7.5m wide, 150m long and 3m high.
5. Adams Solar PV 2 | Photovoltaic
The Adams Solar PV2 solar park is a 75MW plant located in Hotazel in the Northern Cape. According to its owner Enel Green Energy, the plant produces 167GWh of energy per year and assists in displacing 171 700 metric tons of carbon dioxide while meeting the energy needs of 100 000 households annually. Construction on the site began in 2017 and the plant became operational that same year.
6. Dyason’s Klip | Photovoltaic
Dyason’s Klip is situated in Upington and majority-owned by Norwegian power producer Scatec Solar. The project is the first phase of three 86MW PV farms that will have the combined generation capacity of 258MW.
According to the project’s website, the first phase of Dyason’s Klip produces 217GWh of electricity per year.
Once completed, the 258MW Dyason’s Klip solar power complex is expected to provide energy to around 120 000 households and lead to the displacement of more than 600 000t of carbon emissions annually. The last of the three solar plants under construction is expected to reach commercial operation within the next few months.
7. Jasper Power Plant | Photovoltaic
The Jasper Power Plant was jointly developed by SolarReserve, a US developer of utility-scale solar power projects, Kensani Capital Investments, a South African empowerment infrastructure player, and Intikon Energy, a South African developer of renewable energy projects.
The Jasper facility is situated in Postmasburg in the Northern Cape and comprises 39 units of 2MW AC central inverter stations. Some 325 600 such modules were installed at the facility.
According to the project website, the plant is 3km from north to south and produces approximately 180GWh of electricity annually.
8. Konkoonsies II | Photovoltaic
The Konkoonsies II solar power farm is a PV solar farm situated 32km east of Pofadder in the Northern Cape. The facility generates electricity using 40 000 PV panels and is said to supply Eskom with 22GWh of electricity a year.
9. Matla a Bokone Solar | Photovoltaic
Matla a Bokone Solar, formerly known as Droogfontein 2 Solar, is situated in Kimberley and has 261 360 solar modules harnessing the intense Northern Cape sun. According to the project website, this 75MW plant supplies the national grid with 180GWh of energy every year.
10. Mulilo Prieska PV | Photovoltaic
The Mulilo Prieska PV power plant is near Copperton in the Northern Cape. The 75MW solar PV farm is 27% owned by TotalEnergies along with five other partners: Calulo Renewable Energy (25%), Mulilo Renewable Energy (18%), the Industrial Development Corporation (IDC) (15%), Futuregrowth Asset Management (10%) and the local municipality (5%). — (c) 2024 NewsCentral Media
