A German energy company has partnered with a Swedish startup to test the use of salt as a means to store heat and add reliability to the renewable energy sector. The process being tested works as batteries do, storing heat instead of electricity, and countries seeking to cut greenhouse gas emissions are watching to see if it can scale.
Héctor Abruña is a professor in the Department of Chemistry and Chemical Biology at Cornell University and an expert on batteries and energy storage technology. He says the concept being tested works, but has some shortcomings.
“The concept of ‘salt batteries’ has been around for quite some time. The basic idea is that you can store energy (generally as heat) by dehydrating a salt (taking out the water) in an ‘endothermic reaction’. When the salt is rehydrated (water is added), heat is released in an ‘exothermic reaction.’
“This is essentially the same process used in the ‘hot packs’ that you can buy in a pharmacy. It is a simple technology. However, it generally has low energy and power densities and the ‘round trip’ efficiencies are low.”