Steam is generated by conducting a medium through a line which is exposed to solar irradiation. The line has a starting point where a medium supply line issues into the line. The heated medium is conducted away from the at least one line through a drain line. The medium, prior to feeding in at the starting point, is prepared in a power plant component and the medium is supplied at a pressure which is higher than the prevailing pressure in the at least one line, and at an enthalpy which is greater than an enthalpy of saturated water in the line. The medium is fed in as water or water and steam.