The salt melts at . It is kept liquid at in an insulated "cold" storage tank. The liquid salt is pumped through panels in a solar collector where the focused sun heats it to . It is then sent to a hot storage tank. With proper insulation of the tank the thermal energy can be usefully stored for up to a week. When electricity is needed, the hot molten salt is pumped to a conventional steam-generator to produce superheated steam for driving a conventional turbine/generator set as used in any coal or oil or nuclear power plant. A 100-megawatt turbine would need a tank of about tall and in diameter to drive it for four hours by this design.