Eurostat has developed an interactive tool to visualise energy data by means of flow diagrams (also called Sankey diagrams). The tool allows you to build and customise your own diagram by playing with different options (country, year, fuel, level of detail, etc.).
Energy balances can be graphically represented by means of flow diagrams. These flows can be combined, split and traced through a series of events or processing stages. The width of the flows is proportional to the amount of material or energy contained in the respective flow. These visual representations are based on so-called Sankey diagrams, which are typically used to visualize energy transfers between processes. They are named after the Irishman Matthew H. P. R. Sankey, who used this type of diagram in a publication on energy efficiency of a steam engine in 1898.
A Sankey diagram is a very practical tool to represent energy balances in a visual way: an energy balance compiles the contributions and interrelations of various energy commodities (fuels, heat and power, i.e. energy carriers in a marketable form) in the different sectors of the economy (e.g. supply, transformation and consumption) in energy units. While energy balances are often presented in the form of a table or a spreadsheet, a Sankey diagram allows the user to visualise the interrelations of energy commodities in a much more illustrative and intuitive way.
All features and functionalities of the tool are explained in detail in a dedicated Statistics Explained article on Sankey diagrams.