The possibility of using magnesium based eutectic metal alloys as phase change material (PCM) for thermal energy storage (TES) in concentrated solar power (CSP) applications is analysed. An extensive thermophysical characterization of the Mg-51%Zn eutectic metal alloy between room temperature and melting temperature has been performed. The results are compared with some available data in the literature, and differences found are discussed. A comparison with pure, binary and ternary inorganic salts used as PCM is presented highlighting the advantages and disadvantages of the different systems. This alloy is proposed not only as a candidate for latent heat thermal energy storage for direct steam generation (DSG) in CSP applications but for high pressure and high energy steam processes as well. Reported data are essential for ensuing modelling and experimental reactor studies employing this alloy as a PCM for TES. (C) 2014 Elsevier Ltd. All rights reserved.