You're right that solar thermal is technically a type of storage system for solar. But that wasn't countenanced in the article -- wherein we're told the (availability) problem of solar can only be solved by either fossil fuel power plants or storage systems.
My point is that this is either a flawed or a disingenuous premise.
There's myriad ways we could deal with gaps in sunlight availability: nuclear fission (not a fan, but undeniably one way), biofuels (also not a fan, but ditto), reduced demand / opportunistic usage patterns (to ameliorate the effect - not easy, but disturbs me that questions about energy usage never include 'reduce' or 'adapt' in the list of considered answers), and, most importantly, a stack of renewable options that are not constrained by the vagaries of sunlight -- geothermal, wind (terrestrial and tethered), wave, tidal, and hydroelectric spring to mind.
My point is that this is either a flawed or a disingenuous premise.
There's myriad ways we could deal with gaps in sunlight availability: nuclear fission (not a fan, but undeniably one way), biofuels (also not a fan, but ditto), reduced demand / opportunistic usage patterns (to ameliorate the effect - not easy, but disturbs me that questions about energy usage never include 'reduce' or 'adapt' in the list of considered answers), and, most importantly, a stack of renewable options that are not constrained by the vagaries of sunlight -- geothermal, wind (terrestrial and tethered), wave, tidal, and hydroelectric spring to mind.