Sankey diagram
Sankey diagrams are a specific type of flow diagram, in which the width of the arrows is shown proportionally to the flow quantity. They are typically used to visualize energy or material or cost transfers between processes.
Application
They are also commonly used to visualize the energy accounts or material flow accounts on a regional or national level. 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.
Historical Examples
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.
Active Examples
The United States Energy Information Agency (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 2012 include the following diagrams: Energy Flow, Petroleum Flow, Natural Gas Flow, Electricity Flow, and Coal Flow.
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.
See also
- Thermodynamics
- Material flow management
- Grassmann diagram (exergy flow and loss)
More Energy input means less energy wasted
References
External links
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Wikimedia Commons has media related to Sankey diagrams. |
- 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
- Energy in a Sustainability Problem archived presentation from MIT ‐ Professional Education Course, June 2012, which uses both Sankey and Grassmann diagrams to present information
- IEA Energy Balance Flows – Containing International Energy Agency's data on over 150 countries and regions
- Energy in a Sustainability Problem archived presentation from MIT ‐ Professional Education Course, June 2012, which uses both Sankey and Grassmann diagrams to present information