A Solution to Renewable Energy Storage?
Energy storage is the Holy Grail for renewable energy producers. In an ideal world, they would be able to capture that burst of wind at two in the morning and use it to power your coffee maker when you wake up at seven. A solar project in Arizona called Solana is using an innovative solution for energy storage: molten salt.
Imagine pure salt so hot it looks, and moves, like liquid water. This molten salt is the substance inside large insulated tanks that allows the Solana project to store heat for up to six hours. Most of the solar thermal energy is channeled directly to the steam generator that produces electricity, but some of the heat is diverted into heating up these molten salt tanks whose energy can be harnessed long after the sun has set from the sky.
These molten salt tanks make Solana the largest solar thermal project with energy storage in the world. Using heat to store energy is fairly new; some other solar power plants use expensive batteries to store electricity. While storing energy as heat is not mechanically efficient, the economic benefits of producing energy at peak demand may make the molten salt storage worthwhile.
Solar energy typically does a fairly good job of matching peak demands for electricity during the daylight hours, but can fall short in the early morning when people are getting ready for work or in the evenings after the sun goes down. Energy storage capabilities would allow renewable energies like solar to be harnessed around the clock, making them a more formidable competitor to fossil fuels.
(Photo: Solena Project by Abengoa Solar. Article via: New York Times, “Arizona Utility Tries Storing Solar Energy for Use in the Dark”)