This technology uses a field of large sun-tracking mirrors (called heliostats) that reflect the sunlight to a receiver mounted on a central tower in the middle of the mirror field.
Diagram illustrating the central receiver principle (Ref SolarPACES)
A heat transfer medium is pumped through the receiver and absorbs the highly concentrated radiation reflected by the heliostats. The heated fluid is then sent through a heat exchanger, where the thermal energy is used to generate steam and power a turbine. Eskom will use molten salt (a combination of Sodium Nitrate and Potassium Nitrate) as a heat transfer and storage medium in a two tank molten salt storage system.