The South African Government developed the Integrated Resource Plan (IRP) 2010 – 2030, which was promulgated in March 2011. One of the objectives of this plan is to work towards achieving 9 600 MW of power generated by solar energy by 2030. Currently, solar power makes up more than 1 MW of the country’s power grid, under sunny conditions (Winkler, 2015).
There are many benefits of using solar power, however there are negatives too and therefore continuing development of these technologies are required. Concentrated Solar Power (CSP) technology is rapidly developing in South Africa.
CSP technologies are using mirrors, called heliostats, to capture the sun’s energy and convert it into extreme heat. This heat is then transferred by fluids (e.g. molten salt) to a turbine to generate electricity, similar to conventional coal power plants. There are various CSP technologies, these include the tower, parabolic trough, Linear Fresnel, dish engine, and the concentrated photovoltaic system.
The tower system consists of flat mirrors directing the rays of the sun onto a central receiver or tower. Khi Solar 1, currently under construction near Upington will make use of central receiver technology, using molten salt as a heat transfer fluid and for thermal storage.
The KaXu Solar 1 and Xina Solar 1 plants near Pofadder, uses the parabolic trough technology. This technology utilises parabolic or u-shaped trough like mirrors mounted in rows, with a pipe containing oil running along the centre of the mirrors. The oil acts as the heat transfer fluid to the power generator.
The Linear Fresnel CSP technology is similar to the parabolic trough technology. The main difference is that the mirrors are flat and not u-shaped. One of the advantages of this system over the parabolic trough system, is that the mirrors are much cheaper to obtain/produce and therefore it is a more affordable option.
Dish engine systems use mirrors in the form of dishes with the receiver attached to the centre / focal point of the dish. This technology utilises helium or hydrogen gas in cylinders that expands when being heated, which drives the pistons of an installed combustion engine.
The Touws River solar power plant in the Western Cape, utilises the concentrated photovoltaic technology that instead of fluids, contains a photovoltaic receiver.
Concentrating Solar Power (CSP) with Thermal Energy Storage technology is key to the viability of solar power generation in South Africa.
For further reading please visit the following sites:
http://www.energy.gov.za/files/irp_frame.html
http://www.mediaclubsouthafrica.com/tech/4018-khi-solar-one-renewable-energy-for-the-ages
http://www.abengoasolar.com/web/en/plantas_solares/plantas_propias/sud
