The alternatives are also carbon free, which is the point of the parent post.
The comparison is between this and carbon free solar-thermal for energy storage. Saying it doesnt have to be cheaper than solar-thermal simply isnt true.
Fair fair. Unlike traditional solar thermal though, this can just function as regular node on the electric grid (or even a prosumer) so it is decoupled from the attendant variability. As such they are not quite comparable IMO.
