Snakey Diagrams

• Snakey diagrams, sometimes called Sankey diagrams, are used to illustrate energy transfers. They show the amount of energy produced, and how it’s used and lost.

• The width of each part of a Snakey diagram indicates the amount of energy it represents. The wider the segment, the more energy it represents.

• These diagrams are typically divided into useful output energy (the intended result of the energy transfer) and wasted energy (energy that’s lost in the process, often as heat).

• Snakey diagrams are particularly important when examining power stations, as they can visually represent the efficiency of the station.

• Efficiency is an essential concept often depicted in Snakey diagrams. A system’s efficiency is the percentage of input energy that is usefully transferred. The rest is usually lost as heat.

• You can calculate the efficiency of a system using the formula: Efficiency (%) = (Useful output energy ÷ Total input energy) x 100.

• The aim, particularly in electricity generation, is to maximise efficiency. The more efficient a system, the more of its input energy is put to useful output, reducing the waste and cost.

• All devices lose some energy. In a bulb, for example, much of the electrical power is wasted as heat, while the useful output is light. Snakey diagrams show this visually - the width of ‘useful output’ (light) is smaller than the width of ‘wasted energy’ (heat).

• Understanding how to interpret and create snakey diagrams can help identify where energy is being lost or wasted in a system, and potentially inform how it can be made more efficient.

• To create a Snakey diagram, start with the total energy input on the left, draw a line representing that amount. Split the line into ‘branches’ representing the useful output and any wasted energy. Make sure the total width of your branches adds up to the width of your initial energy input.