Symposium FG
Thermal Energy Storage: State-of-the-art Materials and Technologies Towards a Low-carbon Society

Thermal energy storage (TES) technologies that can store and release energy produced by renewables or waste heat in a wide range of temperature and time, are at the forefront to achieve the goal of near zero carbon emissions in 2050 and offer a solution to intermittency or seasonal problems of renewable energy generation. TES may play a significant role across various sectors including energy-intensive industries, buildings and power. Extended research performed in the last decades on sensible (SHS) and latent (LTHS) thermal energy storage and most recently on thermochemical heat storage technologies, credit LTHS of several advantages on SHS including high energy density, a wide range of phase change temperature, chemical stability and affordable prize. However LTHS suffers from various shortcomings. low thermal conduction, poor thermal stability, corrosiveness and leakage in the molten state being among the most critical. Thermochemical solutions, which hold great potential for promoting the development of next generation CSP plants working at temperatures also exceeding 1.000°C, can achieve energy densities higher than SHS, are able to operate under harsher conditions, show good reversibility and quick response in a broad range of conditions, but their insufficient heat and mass transfer performance and overall operation costs are today main drawbacks for its effective introduction into the market. 
Further progress in TES technologies critically rely on the availability of improved/new materials, on how their performances may be optimized by a deeper understanding of working physical chemical processes, on advanced storage concepts and innovative reactor designs. The research process for novel materials has historically been a protracted and arduous undertaking, characterised by iterative experimentation and costly testing, but the recent advancements in AI models (machine learning and deep learning models) have demonstrated the potential for these methodologies to overcome these difficulties, and then to expedite the innovation also in this sector.
Recently, Europe was nominated to become the first regional area with a zero-climate impact in terms of social, economic, and production dimensions by the year 2050. Achieving this objective necessitates a comprehensive transformation of the energy system, encompassing the modernization and implementation of advanced energy infrastructures. These infrastructures are defined by characteristics of smartness, reliability, flexibility, and resilience. Addressing these challenges necessitates the integration of diverse energy processes, a concept referred to as sector coupling or integration. TES technologies, in this regard, find application as intelligent systems for interfacing diverse energy processes. Carnot batteries serve as a prime illustration of this integration.
This symposium aims to bring together researchers and experts from academy and industry to discuss recent advances and new trends of thermal energy storage at both the materials and system levels. Theory and experiment; machine driving approaches such as deep learning and data mining; the progress in TES solutions for renewable energy systems for CSP, in various industrial sectors and for thermal storage in buildings will be object of discussion.