Renewable power-to-heat solution integrated with glycerol-based thermal energy storage system for industrial process heat

The industrial sector is a major contributor to global greenhouse gas emissions, highlighting the need for efficient power-to-heat solutions. This study proposes a novel power-to-heat system integrated with a glycerol-based thermal energy storage and presents the first system-level assessment of pure glycerol as a sensible heat storage material for industrial process heat in the 100–200 °C range. A simplified transient thermal-hydraulic model for hybrid configuration which combines passive storage and cascade operation for supplying heat at a relatively constant temperature is developed. Simulations are conducted for glycerol, molten salt, and thermal oil to produce 170 °C superheated steam for a steam flaking process. The molten salt-based system achieves the highest thermodynamic performance, with a thermal efficiency of 94.47%, a storage utilization factor of 59.2%, and a volumetric energy density of 202.6 kWh th /m 3 . In contrast, the glycerol-based system exhibits lower thermodynamic performance (92.77% efficiency, 42.1% storage utilization factor, and 94.0 kWh th /m 3 ) due to its narrower operating temperature range. The glycerol-based system showed preferable economic performance, achieving the levelized cost of heat (LCOH) of 66.2 USD/MWh th , which is 3.9 and 17.8 USD/MWh th lower than those of the molten salt- and thermal oil-based systems, respectively. Sensitivity analysis shows that electricity cost controls the absolute levelized cost of heat, whereas storage material cost and replenishment of storage material determine the relative economic ranking. These results indicate that glycerol, while thermodynamically less efficient, offers a cost-effective and environmentally benign alternative for thermal energy storage-based power-to-heat solution, making it a viable and competitive option for industrial decarbonization.