Google’s New Energy Storage Moonshot uses Salt and Antifreeze

An article in Bloomberg News reports about a new energy storage system — code named Malta — which is being developed by Google’s parent company Alphabet by a skunk works subsidiary simply named X. X has worked on previous “moonshot” projects such as driverless cars and Google Glass. The goal of Malta, as with other energy storage system, is to be able to capture energy provided by such sources as solar or wind, and store it for later use when the sun is not shining or the wind has dropped.

According to information provided by X to Bloomberg, the Malta system comprises vats of salt and antifreeze along with a heat pump. Here is a simple description of how the system works from the Bloomberg article:

“Two tanks are filled with salt, and two are filled with antifreeze or a hydrocarbon liquid. The system takes in energy in the form of electricity [generated from renewable sources] and turns it into separate streams of hot and cold air. The hot air heats up the salt, while the cold air cools the antifreeze, a bit like a refrigerator. The jet engine part: Flip a switch and the process reverses. Hot and cold air rush toward each other, creating powerful gusts that spin a turbine and spit out electricity when the grid needs it”

While this kind of storage technique is not new, apparently the advantage of the Malta system is able to use inexpensive materials and operate at lower temperatures than similar systems, making it more economically viable. So far only a prototype of the system has been built, but X just has now decided to reveal some information to the public.