TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The solar power plant is a solar thermal power plant, preferably a parabolic trough solar power plant. The steel plant further comprises: an energy storage device, preferably a heat storage tank (40) for storing energy generated by the solar power plant, where the energy is stored in a salt storage device and/or in an endothermically reacting chemical compound, which reacts exothermically during its decay. The smelting unit and the solar power plant are arranged close to each other. The solar power plant comprises a generator (31), which is driven by a turbine, and is arranged within building complex of the steel plant, preferably in the smelting unit. The smelting unit is an electric arc furnace (2) (preferred), an electric reduction furnace, an induction furnace, or a primary energy smelting device. The steel plant comprises at least one further electrical energy consuming device, in addition to the smelting unit, where the solar power plant is designed for supplying energy to the further electrical energy consuming device, preferably the entire steel plant, in addition to the smelting unit in a self-sufficient manner. The further electrical energy consuming device comprises a ladle furnace for overheating the melt produced by the smelting unit, a continuous casting unit and/or a rolling mill having at least one rolling stand, and a water treatment system, preferably a seawater desalination system. The plant comprises a device for energy management, which is arranged for controlling and coordinating the energy requirements, preferably electrical energy of the smelting unit and the further electrical energy consuming device of the steel plant. The power of the generator is equalized to the total energy requirements of the smelting unit and further electrical energy consuming device. The waste heat produced from the steel plant is used by water treatment plant for water treatment. The solar power plant supplies the energy to the smelting unit in a self-sufficient manner. The waste heat produced from the steel plant and/or excess capacity of the solar power plant are used for water treatment, preferably seawater desalination. Preferred Method: The method comprises carrying out continuous-time operation of the electric arc furnace through several melting processes, by continuous-time supply of electrical energy in the form of solar power from solar power plant, and regularly tapping the electric arc furnace under the maintenance of the supply of electrical power such that a sump residue of melt remains in the electric arc furnace after each tapping. The electric arc furnace is continuously charged with the metal-containing solids to be melted. EXAMPLE - No suitable example given.