Gemasolar is the first demonstration plant at commercial scale, based on molten salt receiver and storage technologies, coupled with heliostat and a central tower. SENER has developed and incorporated some major technological advances into SOLAR TWO concept: a newly designed receiver, three times bigger than the one tested in the US. The heliostats set up around the tower reflect and concentrate solar energy onto the molten salt receiver located at the top of the tower. In the receiver, solar energy is transferred to the molten salts circulating inside, which reach a temperature of 565º C. By means of a steam generation system, the molten salts produce overheated steam, that runs a turbine/alternator group to generate electrical energy which then is fed into the power grid. The Gemasolar plant design has been optimised using the SENSOL programme developed by SENER.

The positioning of the heliostats in the solar field was defined using the SENSOL programme.

The 115 m2 heliostats developed by SENER incorporate a mechanism that accurately positions the surface of the reflective glass.

The molten salt receiver, one of the most important components of this technology, has been developed by SENER with the collaboration of CIEMAT.

The system of molten salts stores the excess thermal energy produced during daylight hours and provides the energy required to ensure that the Plant will remain operational for up to 15 hours in the event of zero solar radiation.

Technical data:

• Total mirror surface: 310.000 m²
• Number of heliostats: 2.650 (SENER Mechanism)
• Field surface area: 185 Ha
• Nominal receiver capacity: 120 MWt
• Tower height: 140 m
• Thermal storage capacity: 670 MWhth (15h)
• Turbine capacity: 19.9 MWe
• Thermal cycle efficiency: 40%
• Annual normal direct radiation: 2.172 KWh/m²

Operation:

• NG hibridation: 15%
• Annual equivalent hours: 6.450 h/year
• Annual capacity factor: 74%