Oxygen usage has played a crucial role in the ongoing EAF processimprovement and has enabled furnace operators to optimize thechemical energy input, reaching unprecedented efficiencies and productivity.This article will present the fundamental principles governingthe design of an optimized chemical energy system throughscrap oxy-cutting and melting, decarburisation, post-combustionand slag foaming. It will be illustrated with industrial results obtainedat the Vallourec Mannesmann Saint-Saulve site, where a PyreJetTM and ALARCTM PC system, using the newly designed DRAGON Panel, has been recently commissioned.