Development of a high temperature latent heat storage system for renewable industrial process steam

The integration of fluctuating renewable energy sources into industrial heat supply systems requires thermal storage technologies that combine high flexibility, fast dynamic response and operational robustness. Classical steam generation units are often unable to accommodate rapid load changes or exploit temporary peaks in renewable power generation. To address these challenges, this work presents an ongoing development toward a high temperature latent heat storage system based on a metal alloy phase change material designed for direct process steam generation. The storage concept operates in the temperature range of 250 °C to 500 °C and is intended to buffer surplus renewable electricity while providing industrial steam on demand, enabling partial electrification of process heat. The project focuses on the design, modelling and scale up of a 1 MWh storage module that utilizes the high thermal conductivity and cycling stability of metallic phase change materials. Central engineering tasks include the optimization of heat exchanger structures embedded within the PCM, thermomechanical design of the containment system, and strategies for managing volume changes during melting and solidification. Parallel modelling activities address thermal behavior, dynamic response times and operational stability under realistic industrial load profiles. The charging concept involves direct electric heating or resistive elements, while discharging is realized through steam generation within an integrated heat exchange architecture. A demonstration unit is currently being constructed and will be integrated into an existing industrial steam network to evaluate real world boundary conditions such as fluctuating steam demand, rapid cycling requirements, and interaction with conventional boiler systems. The experimental program will assess thermal performance, system durability, energy efficiency and safety aspects related to molten metal operation. Because the project is ongoing, this contribution presents the conceptual framework, development methodology and planned experimental steps rather than completed results. The work aims to establish a scalable, industrially applicable thermal storage technology that enables flexible renewable based steam supply and contributes to the decarbonization of thermal processes in sectors such as food and beverage, chemicals and pulp and paper.