The power is not "practically free". You have to consider the capital costs of both the generating panels and the storage and the maintenance of both.
Lots of potential there, because it allows for dispersed power, especially for off grid scenarios.
The big thing missing from the article is any mention of price.
Price is essential to understanding the practical potential. Just because sodium is common, does not mean batteries made using it are going to be cheap.
Good post. Thanks.
Quite true - but it’s known that in fact these batteries will be cheap. And the author of this article stated recently on youTube that Tesla itself could, if it came to that, produce such batteries itself.