Storing energy as heat in molten salt, sand, or other media
Thermal storage captures energy as heat (or cold) in materials like molten salt, ceramic bricks, sand, or phase-change materials. It can be used directly for heating/cooling or converted back to electricity using turbines or heat engines.
Thermal energy storage works by heating or cooling a storage medium. Sensible heat storage (molten salt, sand, water) changes temperature. Latent heat storage (phase-change materials) uses phase transitions. For electricity storage, excess electricity heats the medium (resistive heating, heat pumps). To discharge, heat drives a steam turbine, Stirling engine, or other heat engine. Key technologies include: molten salt (proven in CSP), sand/rock storage, MGA (Miscibility Gap Alloy) blocks, and pumped thermal (Malta Inc. uses heated and cooled liquids with heat pumps).
Storage medium: 20-30% | Insulation & containment: 15-25% | Heat exchangers: 15-20% | Power cycle (turbine): 15-25% | Heating elements: 5-10% | Controls & BOP: 5-10%
Thermal storage is the fastest-growing segment for industrial decarbonization. Rondo Energy's brick storage and MGA Thermal's modular blocks are driving innovation. The technology is particularly strong where there's co-located demand for heat.