Solar Thermal Power Plants: Tower

Solar Tower power plants consist of an absorber tower and several mirrors, which concentrate the sunlight on the top of the tower. The mirrors are following the suns position by a biaxial tracking system. Therefore the mirrors are called heliostats.

Functional Diagram

Technology desciption

The suns heat is transported from the absorber to the conventional turbines where the energy is converted into electricity. Besides conventional steam turbines solar towers can also serve integrated gasification combined cycles.

There are three main principles of solar towers which are mainly distinguished in the medium used for the heat transfer from the tower to the steam cycle. In the beginning water was used for this purpose, in order to serve the steam turbine directly. But it is rather complicated to provide steam with constant parameters.

Besides air, todays solar tower power plants use special salt products for heat transfer. Besides the excellent thermodynamic characteristics of the salt it is also used because it is a quite inexpensive method for energy storage. On the other side, combined cycles can be used with a better efficiency by using air instead of salt.

First commercial projects are planned in Spain (PS 10, SOLARTRES)

Assets and Drawbacks

• Extensive reduction of climate and corrosive gases like carbon dioxide, sulfur dioxide, nitrogen oxide and dust particles
• High efficiency because of combined cycle
• Low-cost energy storage
• Possibility of regulating capacity to serve peak load
• Operational range between 10 to several 100 MW

Further detailed information can be found at
Technology Characterization Solar Power Towers

Projects

• Solar One
• Solar Two
• SOLARTRES
• PS10