a. a storage tank;

b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; wherein the MPC includes a core and coating; said core is formulated to have a liquidus temperature of 550-750° C.; said MPC is formulated to be reusable to a temperature of at least 700° C.