Yes I think they store energy in molten sand in the giant Sahara desert solar installations.
Still, there must be considerable energy loss overall.
close, molten salt. solar thermal power is stored in large tanks of molten salts who’s melting temperature is tailored to be slightly lower than the temp of the power tower. By sizing the array field to be 3x the btus needed to run the steam turbines you can store enough heat to run the turbines in darkness 24/7 since salt is cheap and has a high latent heat of fusion and since thermal loss is directly related to surface area and volume bigger tanks are better given that volume goes up at the cube rate while surface area does not. large power towers in sunny area’s can approach the raw cost per btu of heat of natural gas and some of the largest are comparable to coal.Most also have supplemental heaters to back up the array fields should the sun go behind a large frontal system and be cloudy for days. another cheap storage medium being used is gravel heating rocks up during the day and running the brayton cycle turbines off the hot rocks at night.