Abstract: Combined cycle solar power generation is achieved using a primary cycle based on a solar receiver, such as a volumetric absorber, in which compressed air is heated by concentrated solar radiation, coupled with a secondary cycle based on a water/steam circuit driven by exhaust gas from the primary cycle. When the primary cycle is inactive, typically at night time, the secondary cycle can be driven by accessing a heat store of liquid or solid heat storage material, such as a molten salt or concrete blocks, which has been heated earlier during day time operation. The water/steam circuit is reconfigurable between first and second switching conditions, wherein in the first switching condition heat is transferred directly or indirectly from the primary cycle to heat the heat storage material, and in the second switching condition stored heat is transferred from the heat storage material to the water/steam circuit in order to generate steam.