Thermal Energy Storage Technology Roadmap for Decarbonising Medium-Temperature Heat Processes—A Review

This review presents a technology roadmap for Thermal Energy Storage (TES) systems operating in the medium-temperature range of 100–300 °C, a critical window that accounts for approximately 37% of industrial process heat demand in Europe. Decarbonising this segment is essential to meeting climate targets, especially in sectors that are reliant on fossil-fuel-based steam. The study analyses 11 TES technologies, including sensible, latent, and thermochemical systems, covering both mature and emerging solutions. Each technology is evaluated based on technical, environmental, and socio-economic key performance indicators (KPIs), such as energy density (up to 200 kWh/m 3 ), cost per storage capacity (€2–100/kWh), and technological readiness level (TRL). Sensible heat technologies are largely mature and commercially available, while latent heat systems—especially those using nitrate salts—offer promising energy density and cost trade-offs. Thermochemical storage, though less mature, shows potential in high-cycle applications and long-term flexibility. The review highlights practical configurations and integration strategies and identifies pathways for research and deployment. This work offers a comprehensive reference for stakeholders aiming to accelerate industrial decarbonisation through TES, particularly for applications such as drying, evaporation, and low-pressure steam generation.