Sankey diagram Sankey diagrams summarise all the energy transfers taking place in a process. The thicker the line or arrow, the greater the amount of energy involved. This Sankey diagram for an electric filament lamp shows that most of the electrical energy is transferred as heat energy rather than light energy.

We can represent energy transfers by using a Sankey diagram. A Sankey diagram is essentially just a big arrow, which is labelled to show any changes in energy forms. The arrow will split if the energy changes into more than one energy form.

An energy transfer diagram or a Sankey diagram is used to show the transfer of energy across a process or a device. It is a flow diagram in which the widths of the arrows show the relative amounts of each type of energy.

Sankey diagrams show the energy transfers in a system: the energy transferred into the system is shown as an arrow this arrow splits into narrower arrows showing other transfers Sankey diagrams are most useful when the amount of energy in each of the energy sources is known. The width of the arrow is drawn to scale to show the amount of energy.

Sankey diagrams are a data visualisation technique or flow diagram that emphasizes flow/movement/change from one state to another or one time to another, in which the width of the arrows is proportional to the flow rate of the depicted extensive property.