Solar thermal power plants concentrate sunlight to targets containing a "working fluid" (EG. silicon oil, high pressure water, molten salt, etc.) This hot working fluid is pumped (or uses a thermal siphon to move it) between the target and a large storage tank. As power is needed, hot working fluid is taken from the hot storage tank, the heat is converted into electricity by a steam or Sterling engine driving a generator, and then the cooled working fluid goes back to the storage tank.

These plants can easily be designed to produce any number of hours of electricity, with no additional input at night or in the event of a very cloudy day. You just have to make the hot fluid storage tank larger. Which is actually better in terms of heat loss, because the volume goes up by the cube while the surface area goes up by the square of the size.

So these plants (which tend to be more efficient that photovoltaic solar cell-based plants) don't really need battery storage to deliver a planned level of power generation.

For wind power and PV solar arrays: Cool Story, Dude!