Sankey diagram

Example of a Sankey diagram.

Sankey's original 1898 diagram showing energy efficiency of a steam engine.

Sankey diagrams are a specific type of flow diagram, in which the width of the arrows is shown proportionally to the flow quantity.

The illustration shows a Sankey diagram which represents all the primary energy flows into a factory. The widths of the bands are directly proportional to energy production, utilization and losses. The primary energy sources are gas, electricity and coal/oil and represent energy inputs at the left hand side of the Sankey diagram . They can also visualize the energy accounts, material flow accounts on a regional or national level, and also the breakdown of cost of item or services.

Sankey diagrams put a visual emphasis on the major transfers or flows within a system. They are helpful in locating dominant contributions to an overall flow. Often, Sankey diagrams show conserved quantities within defined system boundaries.

History

Sankey diagrams are named after Irish Captain Matthew Henry Phineas Riall Sankey, who used this type of diagram in 1898 in a classic figure (see panel on right) showing the energy efficiency of a steam engine. While the first charts in black and white were merely used to display one type of flow (e.g. steam), using colors for different types of flows has added more degrees of freedom to Sankey diagrams.

One of the most famous Sankey diagrams is Charles Minard's Map of Napoleon's Russian Campaign of 1812. It is a flow map, overlaying a Sankey diagram onto a geographical map. It was created in 1869, so it actually predates Sankey's 'first' Sankey diagram of 1898.

Minard's classic diagram of Napoleon's invasion of Russia, using the feature now named after Sankey.

Active Examples

The United States Energy Information Administration (EIA) produces numerous Sankey diagrams annually in the Annual Energy Report which illustrate the production and consumption of various forms of energy. The report for year 2015 include the following diagrams:

• Energy Flow,
• Petroleum Flow,
• Natural Gas Flow,
• Electricity Flow, and
• Coal Flow.
• Formula1 Budget Breakdown.

Eurostat, the Statistical Office of the European Union, has developed an interactive Sankey web tool to visualise energy data by means of flow diagrams. The tool allows you to build and customise your own diagram by playing with different options (country, year, fuel, level of detail, etc.).

The International Energy Agency (IEA) created an interactive Sankey web application that details the flow of energy for the entire earth. Users can select specific countries, points of time back to 1973, and modify the arrangement of various flows within the Sankey diagram.

The US Department of Energy's Lawrence Livermore Laboratory maintains a site of Sankey diagrams, including US energy flow and carbon flow.

Ben Schmidt, an Assistant Professor of History at Northeastern University, created a Sankey diagram relating majors in college to eventual careers.

Sankey Diagram Software Tools

The following software applications focus on drawing Sankey diagrams.

Name	Creator	First public release date	Operating System	OS Version
Sankey Diagram Generator	Acquire Procurement Services	2016	Web based	Latest browsers with HTML5
Sankey Diagram Creator	InfoCaptor Dashboard Software	2015	Windows,Mac,Web,Linux	Latest browsers with HTML5
Sankey for Android	Jürgen Wilhelm	2014	Android	3.2 or higher
Sankey Editor	Oliver Traun	2011	Windows	XP or higher
Sankey Diagram	squishLogic	2014	Apple iOS	7.0 or higher
e!Sankey	ifu - The Hamburg Institute for Environmental IT	2006	Microsoft Windows	Vista SP2 or higher
s.draw	Altenburger Consulting	2010	Microsoft Windows	3.x or higher
Sankey Diagram Maker	Dr. Hanny J Berchmans	2012	Microsoft Windows	7
Sankey Builder	Rob Potschka	2014	Web based
Google Charts	Google	2014	Web based
wikiBudgets	wikiBudgets	2014	Web based	Latest browsers with HTML5
Python Library for Making Sankey Diagrams	Matplotlib	unknown	Python based Linux, Windows, MacOsX and maybe other Python ports
Raw	Density Design	unknown	Web based
SankeyMatic	Steve Bogart	unknown	Web based
Aster Lens	Teradata	Unknown	Web based client
riverplot	J. Weiner	2014	Windows, Linux, OSX, Solaris	(platform-independent R package )

See also

• Thermodynamics
• Material flow management
• Grassmann diagram [1] (exergy flow and loss)

External links

• Scottish Executive - Energy in Scotland: Supply and Demand
• Irish Environmental Protection Agency - Material Flow Accounts (MFAs) – Demonstration for Ireland - 2001
• sankey-diagrams.com – Blog discussing the usage of Sankey diagrams
• IEA Energy Balance Flows – Containing International Energy Agency's data on over 150 countries and regions
• Eurostat energy flow diagrams – Interactive visualisation tool for the annual energy balance data of 42 countries reporting to Eurostat