Google’s parent company Alphabet’s X Division is trialling an energy storage technology using heated salt and cooled antifreeze.

The system uses electricity to produce a stream of hot air and another of cold air in the same way as a refrigerator produces cold and expels warm air.

The hot air is used to heat salt, which can store energy for days, while the antifreeze remains cold.

When power is needed the system is reversed. Hot and cold air are released and rush towards each other creating a powerful stream which drives a turbine to produce electricity.

The technology is based on research by Robert Laughlin, a Nobel prize-winning physicist,  who is now a consultant to the project. Although components of the technology are well established, the X Division implementation is able to operate at a much lower temperature so it doesn’t require specialized, expensive ceramics and steels.