CSP Overview

CSP with heat energy storage is the only renewable energy technology with the ability to deliver electricity consistently during peak times, when it is needed most.

How CSP Works

Concentrating solar power (CSP) works on the same principle as a conventional power station, but instead of using coal as the source of fuel to generate electricity, CSP uses the energy from the sun. CSP systems use reflectors to focus sunlight onto solar receivers to heat a working fluid. The heat is then used to create high-temperature steam, which is used either in a conventional turbine to produce electricity or in industrial process applications.


Because heat can be stored more cost-efficiently than electricity, CSP technology also provides the foundation for a thermal energy storage system that can support plant operations according to market and power system needs, rather than depending on the immediate availability of sunlight.

In a solar thermal system with thermal energy storage, heat is transferred to a thermal storage medium, usually molten salt, in an insulated reservoir or tank during the day, and withdrawn for power generation at night. This allows the use of solar power for base-load and peak-time generation, when it is needed most, and gives it the potential to match coal- and natural gas-fired power plants.

South Africa’s first three CSP power stations will include storage ranging from two to nine hours, giving them the ability to supply electricity to the national grid at peak times, when it is needed most.


CSP aligns with growing energy demands, renewable mandates and environmental sensitivities:

  • Concentrating solar power is reliable, flexible and dispatchable
  • Concentrating solar power is environmentally sustainable, reducing carbon emissions and improving air quality for local communities. When coupled with dry-cooling, CSP technologies use little water
  • When CSP is integrated with thermal storage, generation is not constrained to when the sun is shining
  • Solar thermal supports the creation of more local jobs than other forms of renewable energy; and local manufacturing of components on a significant scale also contribute to economic development

For more on CSP, read the Frequently Asked Questions (FAQs) here.