The amount of energy in the sunshine that reaches the planet is thousands of times greater than what humans can now absorb. One potential answer to the issue of transforming solar energy into usable energy is offered by solar thermal systems. The designs of large-scale solar thermal plants vary, but they all focus sunlight to heat a material, which is subsequently transformed into electricity using the heat that was "stored" in the material.

Electricity is generated at the Solana Generating Station in Arizona's Sonora Desert at a rate of 280 megawatts. The system makes use of parabolic mirrors to direct sunlight onto pipes containing heat transfer fluid (HTF). Next, the HTF performs two actions: Water is converted into steam, which then spins turbines to generate energy. Melts and warms a salt mixture that serves as a thermal energy reservoir. After the sun goes down, the molten salt mixture can then release enough of its stored heat to produce steam to run the turbines for 6 hours. Molten salts are used because they possess a number of beneficial properties, including high heat capacities and thermal conductivities