Central-tower technology

Torresol Energy has pioneered the application of technological solutions for central tower and heliostat plants such as the high concentration receiver system and high-temperature molten-salt storage system.

How the technology works

In central tower plants, heliostats (flat mirrors) reflect solar radiation onto a receiver located at the top of a tower through which molten nitrate salts flow. The salts are impelled from a ‘cold tank’ to a receiver located at the top of a tower where they are heated to 565ºC. The hot salts then descend to the heat exchanger and generate water vapor.

In surplus-energy conditions, in which the heat radiation received is more than sufficient to cover the turbine's demand, some of the salts are stored in a hot tank, saving the heat to be used when solar radiation is low. The salts transfer the stored heat and continue to generate electrical power.

Gemasolar

Gemasolar, Torresol Energy property , is the first commercial plant to generate electricity with solar technology using a central tower receiver, a heliostat field and a molten-salt heat storage system.

This installation has:

• Power of 19.9 MW
• More than 2,600 heliostats and a surface area of 185 hectares
• A molten-salt heat storage tank

The advantages of the molten-salt heat storage tank technology of the Gemasolar plant include the following:

• Molten-salt storage tanks permit independent electrical generation for up to 15 hours without any solar feed
• The notable increase in the plant's power efficiency guarantees electrical production for 6,500 hours a year, 1.5 to 3 times more than other renewable energies
• The turbine can be operated at normal capacity when there is loss of or a reduction in solar radiation due to clouds.