Latent heat Thermal Energy Storage systems based on CMC at Ultra-high Temperature – LaTESt-CUT

Renewable energy sources fluctuations demand for novel large-scale energy storage solutions. In this framework, Ultra-High Temperature Latent Heat Thermal Energy Storage (UHT-LHTES) systems are gaining attention for their potential to efficiently store and convert energy at temperatures above 1000°C. These systems can capture solar energy, high-temperature waste heat, or electricity and convert it back into heat or electricity when needed, supporting grid stability and renewable integration. Due to high energy density, UHT-LHTES systems have compact designs, making them suitable for decentralized storage.
However, operating at UHT presents engineering challenges, regarding two aspects : one is the development of a suitable thermal storage material and the other is the durability and reactivity of the housing materials. As latent heat storage materials, state-of-the-art silicon alloys have the major drawback of containing a large amount of boron, which is quite expensive and poses supply sovereignty problems. Here it is proposed to replace them by new compositions allowing to meet the specifications at a lower cost. Concerning housing materials, Ceramic Matrix Composites (CMCs) are ideal candidates due to their exceptional high-temperature stability, corrosion resistance, fracture toughness, thermal shock resistance, and low density.
The LaTESt-CUT project will address these challenges by proposing a modular compact design of a UHT-LHTES prototype (TRL4) utilizing cost-effective CMC-based solutions and advanced pressure-less joining methods. The efficiency of this system will be pushed up to its limit through the application of high melting point metallic Phase Change Materials (mPCM), as silicon-based alloys, testing their interaction and thermochemical compatibility with the CMC materials proposed in the expected application environment up to 1300°C under thermocycling conditions.

Cost-effective energy storage solutions are essential for a low-carbon society and a flexible power grid. UHT-LHTES systems can improve the efficiency and sustainability across various high-temperature sectors (e.g. concentrated solar power, steelmaking, glass manufacturing) by enabling energy recovery thus supporting decarbonization efforts. Two major challenges for UHT-LHTES deployment in industrial settings are the development of more affordable mPCM materials respecting all requirements and the development of housing materials withstanding high temperatures and corrosive environments while maintaining structural integrity over extended cycles.