Siemens prepares to build molten-salt power plant

Siemens is to build a test power plant that will operate with molten salt as the heat-transfer medium.

The technology is to be tested and optimised over three years at Evora University in Portugal.

The aim of the Siemens-led research project is to enhance the economy and reliability of parabolic-trough power plants.

This type of solar thermal plant concentrates sunlight using parabolic mirrors on a receiver tube containing a heat-transfer medium.

Today’s commercial parabolic-trough power plants use thermo oils as heat-transfer medium, allowing continuous operation at a temperature as high as 400°C, but the 300m-long test loop is to be operated using molten salt at temperatures of more than 500°C.

Siemens believes that this high-temperature steam will lead to the more efficient operation of the steam turbine.

The potential offered by different types of salt is to be investigated at the test facility equipped with receiver tubes made by Archimede Solar Energy (ASE).

The new salts will include not only a refined form of the solar salts customarily used to date but also salts of a different composition.

According to Siemens, one of the challenges involved in the development of new salts is to find media with a low melting point, so that the potential risk of freezing in the systems carrying the salt and heat losses can be significantly reduced.

The project forms part of the High-Performance Solar Thermal Power research project sponsored by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety.

Partner companies include the German Aerospace Center (DLR), K+S, Senior Berghöfer and Steinmüller Engineering.

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