Rankine cycles for low to medium power and low temperature heat using water as working fluid, were almost written off. The main arguments speaking against them are reviewed in this paper and the conceptual design of the equipment entirely revisited. An advanced design, using up-to-date technologies, allows water/steam driven Rankine cycles to be placed back into their right place. Calculations made on a conceptual design basis show that both competitive cost and efficiency levels can be achieved. Making use of the right technologies and being able to open his view, allow therefore water as an environmentally friendly fluid to be used more largely in the low to medium power range.