I really like the concentrated solar systems that use molten salt, where rather than heating water directly, molten salt is heated and stored In large insulated tanks and tapped off to a heat exchanger to run the turbines, thus allowing power generation to match demand and continue at a constant rate even when light level very (such as at night).

One interesting idea is to use a concentrated solar system to run an Einstein–Szilard refrigerator, or some other absorption refrigerator cycle.