Power of salt
Google parent Alphabet is looking to use salt to solve storage issues around renewable energy. Via its X moonshot unit, the company is working on a prototype system to store renewable energy that isn’t needed as it’s produced by utilising large tanks of molten salt.
Alphabet tags the Malta initiative ‘a grid-scale energy storage technology that can timeshift renewable energy’, adding that it outperforms current solutions that are expensive and aren’t able to capture all of the energy produced by renewable sources.
With Malta, energy is stored as thermal energy – both heat and cold – with the former in the form of liquid salt and the latter as chilled liquid. The temperature difference between the two is converted back into electrical energy by a heat engine (the reverse of a heat pump).
Alphabet reckons Malta is pretty much good to go.
“After more than two years… we have detailed engineering designs that are nearly ready to be turned into real machinery – down to the exact angle of each blade in a turbine and the strength and thickness of the material used,” Alphabet says.
And the company states that Malta uses inexpensive components, with much of the system relying on conventional technology, while salt is easily extracted from the earth and able to be used over and again without toxic by-products.
Also, Malta isn’t dependent on particular weather or specific locations and can be sited near the renewable energy source, or where there’s high demand on the grid.
The system is long-lasting and easy to scale up. Adding more storage capability, means simply slotting more tanks of salt and tanks of cold liquid, Alphabet states.
Image: Steve Mullins