Sankey Diagrams are a way of representing Input/Output energy in a simply manner.
E.g:
[img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1487705212/sankey_diagram_pcsefi.svg']
A more practical example:
[img style='min-width:40vw;' src='https://res.cloudinary.com/deylrqt2d/image/upload/v1487706018/sankey_diagram2_z1gjwa.svg']