# Data Story Brief — The Hidden Cost of Clean Energy

## Subject
A scrollytelling explainer on how the renewable energy boom is stressing global supply chains — from polysilicon to lithium to copper wire — and what that means for the energy transition timeline.

## Narrative hook
One disruption ricochets through the system. The rush to solar and EVs is creating new chokepoints that echo the chaos of the 2021 chip shortage.

## Section outline

1. **The Rush Begins** — Global solar installations triple in five years. Headline stats set the scale.
2. **The Polysilicon Pipeline** — China controls 80% of solar-grade polysilicon. Map + timeline chart.
3. **Cobalt's Long Road** — 70% of cobalt comes from the DRC. Heatmap of矿区 (mine sites) and logistics routes.
4. **The Copper Constraint** — EV motors need 4× more copper than ICE cars. Bar chart + price history.
5. **What This Means for 2030** — Projection panel: three scenarios, cost implications, policy levers.

## Chart plan

| Section | Chart type | Purpose |
|---|---|---|
| 1 | Area chart | Solar installations 2015–2024 |
| 2 | Choropleth / dot map | Polysilicon production by country |
| 3 | Heatmap | Cobalt mine output concentration |
| 4 | Grouped bar chart | Copper intensity: EV vs ICE vs Grid |
| 5 | Scenario fan chart | Cost projections under 3 policy paths |

## Visual direction
Editorial infographic palette — deep navy (#0d1b2a), teal (#00b4d8), amber (#ffd60a), off-white (#f8f9fa). Sans-serif throughout. Clean data-ink ratio, generous whitespace between sections. Scroll reveals drive section transitions; no page-turn gimmicks. Mobile-first: charts reflow to single column, annotations anchor below.

## Interaction
- Mouse + keyboard + touch
- Progress bar at top
- Chapter dots (5) with active state
- Persisted scroll position on reload

## Annotations
- Glossary panel (expandable) for technical terms (polysilicon, Cobalt, LFP, NMC)
- Annotation tooltips on chart data points

## Output files
- `index.html` — self-contained, no external images, all CSS/JS inline
- `PROMPT.md` — this file