Projects Quantum Solar tm Solar done right! © QUANTUM SOLAR 2014 Efficiencies & Performance A variety of fluids can be used to transport the sun's heat, including water, air, oil, and sodium. Molten salt is used in solar power tower systems because it is liquid at atmospheric pressure, provides a low-cost medium to store thermal energy, its operating temperatures are compatible with today's steam turbines, and it is non-flammable and nontoxic. Monday January 25th Heat storage enables solar thermal plants to produce electricity during hours without sunlight. Heat is transferred to a thermal storage medium in an insulated reservoir during hours with sunlight, and is withdrawn for power generation during hours lacking sunlight. Thermal storage mediums will be discussed in a heat storage section.