Influence of atmosphere and austenitic stainless steel on the solar salt corrosivity.

The utilization of the Solar Salt (60 wt%NaNO/40 wt%KNO) mixture as a Thermal Energy Storage (TES) medium is gaining importance due to its scalability and cost-effectiveness. However, the corrosion of metallic components presents a significant challenge. This study explores the intricate interplay between salt chemistry and its corrosivity, particularly at elevated temperatures exceeding the state-of-the-art bulk temperature 565 °C.

Demonstration of the stabilization of solar salt at 620 C with a semi-closed configuration in a 100 kg-scale.

Among the variety of energy storage techniques thermal energy storage (TES), based on molten salts, is already in use for the storage of heat in a gigawatt hour scale. At the time of writing virtually all TES in CSP utilize Solar Salt (60 wt-% NaNO and 40 wt-% KNO) due to its competitively low price, low vapor pressure and non-toxicity. On the downside, the operating temperature is limited to 560 °C based on its thermal stability.