Economic Evaluation of a Concrete-Based Tank for Molten Salts in Concentrating Solar Power Plants

Advancements in concentrating solar power (CSP) plants are essential for the wider adoption of these technologies. Increasing the operating temperature of the plants is one of the most promising ways to achieve further cost reductions and performance improvements. In this context, progress in supporting components—such as molten salt tanks—is critical to enable these advancements. This study compares a novel molten salt tank based on a refractory concrete formulation with a conventional design made from 347H stainless steel over the period 2015–2025. The prices of refractory concrete and stainless steel were analyzed across the decade to estimate the costs of the corresponding TES tanks in 2015 and 2025. The results showed that, while the concrete-based tank was more expensive than the conventional tank in 2015, the situation reversed by 2025, with the conventional stainless steel solution becoming 11% more expensive than the refractory concrete alternative. Additionally, an analysis of the producer price indexes for both materials highlighted that concrete exhibited a more stable price trend compared to stainless steel, which was subject to greater intra- and inter-year fluctuations. Finally, a brief examination of the 347H stainless steel production chain identified key causes of price volatility, such as the high geographic concentration of its main raw material extraction sites worldwide.