Siemens Energy has secured a role in one of the world’s first commercial solar tower power projects through a contract to supply a steam turbine for the Solar Tres plant.
The German equipment manufacturer has been awarded a contract by Spanish engineering group Sener to supply an industrial steam turbine to the 19 MW plant, located near Seville, Spain. The project is the first commercial-scale demonstration of solar tower technology using molten salt coupled with a heliostat and a central tower.
Siemens will supply an industrial steam turbine especially adapted to the solar technology requirements of the power plant, which will feature a 120 m-high tower and occupy an area of 320 000 squae metres.
The steam turbine will be a two-cylinder reheat SST-600 unit and will become a reference product for future solar tower projects, says Siemens.
In the Solar Tres power plant, sunlight will be bundled by sun-tracking mirrors (heliostats) and reflected directly onto a receiver on top of the tower. Temperatures in the receiver will reach 850°C and will allow molten salt inside the receiver to be heated up to 565°C. The molten salt then flows through a heat exchanger, allowing steam to be raised to drive a steam turbine generator.
The Solar Tres plant includes a mechanism that prevents the steam turbine from cooling down too much at night and correspondingly shortens the warm-up phase on start-up. The use of molten salt allows excess thermal energy produced during the day to be stored and means that the plant can remain operational for up to 15 hours in the event of zero insolation.
According to Sener, the location of Solar Tres has recorded high levels of direct annual solar radiation energy and offers outstanding meterological conditions for the operation of the plant.
The technology to be used at Solar Tres is based on Sener’s Solar Two plant, an experimental project that operated for three years in the USA.
