Understanding the effects of energy within all the sciences. The energy concept is one of the most important ideas for students to understand. Looking at phenomena through the lens of energy provides powerful tools to model, analyse and predict phenomena in the scientific disciplines. The cross-disciplinary nature of the energy concept enables students to look at phenomena from different angles, helping them to develop a more integrated understanding of science. In this article we will discuss the role of four key ideas about the energy concept that students need to understand, namely energy transformation, transfer, degradation and conservation. Based on research showing that students progress from an initial understanding of energy transformation and transfer, through understanding degradation to finally understanding conservation, we will propose a teaching sequence that may help to successively build an integrated understanding of energy throughout physics instruction based on these key ideas.