An economic evaluation regarding the industrial photosynthesis of fine chemical rose oxide using solar light is given and compared to conventional lamps as light source. A plant leaching a capacity of 100 t/a was designed containing app. 1,900 m(2) of parabolic troughs, 1,500m(2) of flatbed reactors of 32 high-pressure mercury lamps doped with Thallium iodide (TlI) as a photounit. The investment and production costs were compared and graded. We reached the conclusion that solar application is more profitable than the lamp driven one.