Caldera's Megacell modular heat storage technology converts solar power into on-demand heat, replacing gas boilers

https://pv-magazine-usa.com/2024/10/02/storing-solar-power-through-aluminum-rock-composite/

"recycled aluminum/ volcanic rock/ proprietary material preventing  radiative loss, composite stores heat up to 500°C, producing up to 210°C hot water/ steam... enclosed in vacuum-insulated (prevents heat conduction/ convection loss) chamber heated using electric elements... produces steam through small amount of water passed through coil within core, extracting stored energy... varying water volume controls power output... being modular allows storage capacity up to 100 MWh... built 4 MWh first demonstrator"