Just typical bad writing by one who doesn’t know the subject matter or care to learn it.
The project proposes to store energy as heat in the molten salt and tap it to run generators, presumably by generating steam to power turbines.
And of course, the really key question IS "why is molten salt the preferred storage medium?" There's probably something interesting there. But that didn't seem to interest the reporter, because there's no information on why this was chosen.