This chapter addresses the principles of achieving optimal energy utilisation. The principle is that the analysis of the process as a system leads to much more efficient solutions for saving energy than just by optimising the stand-alone units. Namely, this method can set optimum targets for energy saving, just from enthalpy-temperature profiles, well ahead the detailed design of heat exchangers. In a saving project, Pinch is the place where the heat transfer between hot and cold streams is the most important constraint. The Appropriate Placement of unit operations with respect to Pinch gives valuable insights for improving the energetic efficiency of the whole process.