Energy Flow Sankey Diagram Generator

What is an Energy Flow Sankey Diagram?

An energy flow Sankey diagram is a multi-stage inflow-outflow chart built to trace where energy comes from, how it is transformed, and where it finally goes. It splits the whole chain into columns of nodes — typically a starting column of sources (nuclear, fossil fuels, renewables, imported energy and so on), middle conversion and carrier stages (power generation, refineries, gas networks, district heating, extraction), and a final column of end uses (transport, industry, residential, heating and cooling, losses and exports). Ribbon width is proportional to value and each column is exactly conserved, so every unit of energy that is split, merged or lost at each step can be read at a glance.

Unlike poster-style multi-stage Sankeys, this energy-flavored look stays closer to official energy statistics: nodes are thin right-angled vertical bars with an earthy multi-hue palette (greens, blues and olives with magenta, red and amber accents). Ribbons are not flat single colors — each one blends along its flow from the source node color to the target node color and is drawn at very low opacity (around 0.2), so overlapping flows darken naturally into layered depth. Most importantly, every node label sits to the right of its bar, vertically centered with no pill background, so it never covers the ribbons beneath. The result is a clean, high-density layout that suits rigorous energy reports and policy briefs.

Features

• Template driven, auto-layered: download the CSV template, fill in source,target,value, upload, and the tool derives every node’s level from the flow hierarchy — no manual stage declaration
• Deep free-depth levels: up to 200 rows and 20 nodes per stage, enough for a full source → carrier → end-use chain spanning five or more columns, and compatible with two-column and free-depth structures
• Source-to-target gradient ribbons: each ribbon computes its own horizontal gradient from source color to target color and is drawn at ~0.2 opacity, so overlaps deepen naturally
• Right-aligned labels, no background: every label sits to the right of its bar, vertically centered, with no pill — the ribbons stay fully visible
• Earthy multi-hue palette: a 20-color sequence of greens, blues and olives, distinctable across hundreds of flows yet coherent as a whole
• Three palettes + light/dark modes: Earthy Multi, Elegant Cool and Morandi Warm switch in one click, and dark mode brightens colors for contrast on dark canvas (export bundles the canvas color)
• Multiple export formats: high-res PNG (2x pixel ratio) and vector SVG, editable in design software
• Local privacy: all data is parsed and rendered in your browser, never uploaded

Use cases

• Energy statistics and accounting: primary energy → conversion → transmission → end use, fully showing how generation, heating, transport and industry consume and lose energy
• Carbon and renewable analysis: coal, gas, oil, nuclear, wind, solar and biomass split by end use, supporting decarbonization and energy-transition arguments
• National and sectoral energy reports: a rigorous, high-density overview chart for white papers and annual reports
• Budget and money flows: total budget → department → project → purpose, revealing where each unit of funding is reallocated
• Supply chain and logistics: supplier → transit → hub → terminal market, showing step-by-step distribution
• Data journalism and research: a professionally rendered, earthy-toned multi-stage flow chart for feature stories and papers

How to use

1. Click “Download CSV template” to grab a sample file (containing roughly a full source → carrier → use chain)
2. Fill in your data in the template format: source,target,value
3. Click the upload area or drag your CSV file onto the page
4. The energy flow Sankey renders automatically — switch palettes and light/dark mode as you like
5. Optionally type a title in the “Chart title” box (a large bold title appears by default); leave empty to hide it
6. When satisfied, click “Download PNG” or “Download SVG”

Data format

Field	Required	Description
source	yes	outgoing node name (upstream source / carrier)
target	yes	incoming node name (downstream carrier / use)
value	yes	flow amount (positive number); ribbon width is proportional

Limits: up to 200 rows; no more than 20 nodes per stage. The number of stages is derived automatically from the flow hierarchy, with data required as a one-way layered structure — a circular flow triggers a warning.

Note: a name appearing more than once is treated as a single merged node. If different stages really need the same category name, prefix it per stage (e.g. Stage1-Coal and Stage3-Coal), otherwise they will be merged.

How to read this chart

Read the stages from left to right: first see how the sources spread the total, then follow the ribbons to see which carriers each unit of energy passes through and which end uses it reaches. Because every column is conserved, the width of any ribbon represents both absolute flow and share. The earthy palette separates source branches, and the gradient direction tells you where each flow comes from and where it goes. Hover over a ribbon or node to see the exact value.

About Gotokit

Gotokit builds simple, efficient and beautiful online tools. This energy flow Sankey generator runs on the ECharts engine — no sign-up, open and use, fully local data processing to protect your privacy.