Visualizing Energy Flow: A Creative Guide to Crafting Compelling Sankey Charts

Sankey diagrams, named after Sankey’s work on water flow, have evolved into a powerful tool for visually representing the flow of items between different categories. In the context of energy management, sankey diagrams provide an elegant way to understand and communicate how energy is produced, used, and transformed at different points in a system. Whether we’re looking at the flow of electricity in a power grid, the transformation of fuel into energy in an engine, or the distribution of greenhouse gases in an urban environment, sankey diagrams offer a clear and engaging way to see the big picture, while also pinpointing areas of inefficiency or need for resource optimization. In this guide, we’ll explore the creative process of crafting compelling sankey charts, starting from concept to final visualization.

Understanding the Basis of a Sankey Chart

A sankey chart is a type of flow diagram that uses width to represent the amount of flow. The most common application of sankey diagrams is in the visualization of energy flows or energy balances. In a basic sankey diagram, you’ll typically see a series of links (often referred to as “flows”) running between boxes representing the inputs and outputs of a system. The width of these links is proportional to the amount of substance (e.g., energy, water) flowing through them.

Components of a Sankey Diagram

1. Inputs and Outputs: These are the starting and ending points of the flow. Typically represented as blocks on either side of the diagram.
2. Processes: Intermediate states through which the flow passes, represented as subcategories within the diagram.
3. Flows: The arrows or lines representing the flow of energy or substance, with the width indicating the flow’s magnitude.

Crafting a Compelling Sankey Chart

1. Define Your Visual Purpose

Before you start putting pen to paper (or mouse to screen)—or now, data into software—think about why you want to create a sankey chart in the first place. Are you aiming to explain a complex system to a layperson? Demonstrate the efficiency or inefficiency of a particular process? Regardless of your purpose, clarity should be a priority. Choose a medium (e.g., PowerPoint, R, Tableau) that allows you to achieve your goals efficiently and intuitively.

2. Gather Your Data

Accuracy is key in a sankey chart, as it deals with quantities. Make sure your data is reliable, up-to-date, and reflects the scope of your visualization accurately. Data on energy production, consumption, or transformation rates can typically be found through official energy agency publications or industry reports.

3. Organize Your Data

Sort your data in such a way that the flow makes sense visually and narratively. Intermediate processes should come in a logical sequence, and the starting and ending points should clearly indicate the inputs and outputs of your system of interest.

4. Decide on Your Scales

Since the width of each flow corresponds to the amount of energy or substance flowing, it’s crucial to define a scale that’s clear and intuitive for the viewer. If you’re visualizing energy flow, you might choose to scale the widths based on percentage of total flow, or a simple magnitude (e.g., x100%, x1,000%, etc.). In any case, make sure to include a secondary scale on the diagram to allow viewers to get an idea of the flow’s magnitude instantly.

5. Choose Your Channels

Decide whether the visualization will be static or interactive. Interactive sankey diagrams, particularly those embedded in a web page, offer viewers the ability to query and zoom into parts of the diagram, making it a powerful tool for data exploration. Whether static or interactive, choose a platform with a user-friendly interface that allows you to adjust the look of your sankey chart to match your presentation’s aesthetics.

6. Enhance with Context and Color

While the width of each flow should convey the amount of energy or substance passing through it, color coding can be used to break down the data further. For instance, different colors can represent different types of energy production or consumption. Legends and labels should be clear and placed in a spot where they won’t detract from the overall flow of the diagram.

7. Feedback Loop

Before finalizing your sankey chart, test it on a few friends or colleagues. Does the flow visually make sense? Is the scale clear? Are the categories intuitive? Use this feedback to refine your visualization.

Wrapping Up

Creating a compelling sankey chart is as much an art as it is a science. With the right data, a clear purpose, and a bit of creative flair, you can present complex energy flows in a way that’s both engaging and informative. Whether you’re an energy analyst, a data scientist, or a sustainability advocate, a well-crafted sankey chart can be a powerful tool to communicate your findings and drive action.

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SankeyMaster is your go-to tool for creating complex Sankey charts . Easily enter data and create Sankey charts that accurately reveal intricate data relationships.