Add column history section with exact dates, fix REE links, remove helper column note

README.md

@@ -18,28 +18,24 @@ size_categories:
 task_categories:
 - time-series-forecasting
 license: cc-by-4.0
-datasets:
-- ree
 ---
 
 # REE Iberian Peninsula Electricity Generation
 
-Electricity **demand and generation by source** for the Iberian Peninsula, sourced from [REE (Red Eléctrica de España)](https://demanda.ree.es/). Covers **2008–present** at **5-minute resolution**, fully deduplicated.
+Electricity **demand and generation by source** for the Iberian Peninsula, sourced from [REE (Red Eléctrica de España)](https://www.ree.es/). Covers **2008–present** at **5-minute resolution**, fully deduplicated.
 
 ## Dataset Summary
 
 - **1,931,443 rows** × 38 columns
 - **Date range**: 2007-12-31 → 2026-05-14
 - **Resolution**: 5 minutes
-- **Source**: [REE open data API](https://www.ree.es/en/transparency/opens-data)
 
 ## Columns
 
-All 33 columns from the REE API are included, plus 5 time helper columns (`year`, `month`, `day`, `hour`, `date`). All values in **MW**.
+33 columns from the REE API, plus `ts` (timestamp). All values in **MW**.
 
 | Column | Description |
 |---|---|
-| `ts` | Timestamp (5-minute intervals) |
 | `dem` | Total electricity demand |
 | `eol` | Wind (Eólica) |
 | `nuc` | Nuclear |
@@ -65,6 +61,18 @@ All 33 columns from the REE API are included, plus 5 time helper columns (`year`
 | `impFra` / `impPor` / `impMar` / `impAnd` / `impTot` | Imports by origin / total |
 | `dif` | Balancing difference |
 
+## Column History
+
+The API schema has always contained all 33 columns, but several remained at zero until the corresponding infrastructure came online or was added to reporting:
+
+| Column(s) | First non-zero | Context |
+|---|---|---|
+| `icb` | 2013-02-28 08:50 | Islanded consumption blocks added to reporting |
+| `solFot`, `solTer`, `termRenov`, `cogenResto` | 2015-04-30 22:00 | Solar and renewable thermal generation began being reported separately |
+| `bat`, `consBat` | 2024-10-24 12:50 / 13:10 | Grid-scale battery storage deployed |
+| `vap` | 2025-07-14 14:00 | Steam generation added to reporting |
+| `aut` | 2007-12-31 → 2025-12-11 | Self-generation reporting discontinued from 2025-12-12 onward |
+
 ## Usage
 
 ```python
@@ -75,11 +83,10 @@ ds = load_dataset("daniel-dona/ree-data")
 
 ## Notes
 
-- **Coal phase-out**: Spain's last coal plants closed in 2025 (`car` → 0 from mid-2025).
-- **`sol` vs `solFot`/`solTer`**: `sol` is a legacy aggregate. Prefer `solFot` + `solTer` for accurate solar.
 - **`hid` negative values** indicate net pumping (pumps consume more than turbines generate).
+- **`sol` vs `solFot`/`solTer`**: `sol` is a legacy aggregate. Prefer `solFot` + `solTer` for accurate solar.
 - Static snapshot as of 2026-05-14.
 
 ## License
 
-**CC-BY-4.0**. Underlying data published by [REE](https://www.ree.es/en/transparency/opens-data) as open data.
+**CC-BY-4.0**. Underlying data published by [REE](https://www.ree.es/) as open data.