Central tower | Torresol Energy

Central tower

Torresol Energy is a pioneer in applying technological solutions for plants with central towers and heliostats, such as the high-concentration receiver and the high-temperature storage of molten salts.

How the technology works 

In the central tower plants, the heliostats (plane mirrors) reflect solar radiation into a receiver located at the top of a tower in which molten nitrate salts circulate. These salts are driven from a ‘cold tank’ to the receiver at the top of a tower, where they heat up to 565ºC. These hot salts go down to the heat exchanger to generate steam.

In conditions of maximum insolation, when the heat radiation received is greater than the demand of the turbine, a part of these salts is stored in a hot tank that can conserve the heat to use it in times of low solar radiation. The stored salts then transfer the heat to the steam generation system, and continue to generate electric energy.


Gemasolar, owned by Torresol Energy, is the first commercial-scale power plant with central tower receiver technology, a heliostat field and a heat storage system for these salts. This facility has:

  • A power of 17 MW.
  • More than 2,650 heliostats and a surface area of 195 hectares.
  • A molten salt heat storage system. (should we mention the hours?)
  • 8,000 tonnes of salts.
  • 150m tower.

Among the benefits of molten-salt storage technology in the Gemasolar plant, it is worth highlighting the following:

  • The storage tank for high-temperature salts, which allows for 15 hours of power generation autonomy when there is no sunlight.
  • The significant increase in energy efficiency, in ensuring power production for more than 4,500 years per year, 1.5-2 times higher than other renewable energies.
  • The handling of a single thermal fluid, of an inorganic basis and harmless environmental characteristics (and therefore non-pollutant), in a very small area of the plant.