TenneT AFRR Bid Ladder Archive

Historical archive of TenneT AFRR bid ladder snapshots, stored as a Delta table. The full archive is available as a download from the GitHub Releases page — no API key required.

How It Works

A cron job runs every 15 minutes on a VPS:

1. Fetch — pulls the current bid ladder from the TenneT API and stores sampled snapshots into a local Delta table
2. Backup — once a day, the Delta table is packed into a .tar.zst archive and uploaded to the afrr-delta-backups GitHub Release, keeping the last 14 daily snapshots

The repo contains only code. All data lives in the Release assets.

Getting The Data

Download the latest archive and extract it:

gh release download afrr-delta-backups \
  --repo wouterbles/tennet-afrr-archive \
  --pattern "*.tar.zst" \
  --dir /tmp/

mkdir -p ~/tennet-afrr-data
tar --zstd -C ~/tennet-afrr-data -xf /tmp/afrr_delta_*.tar.zst
rm /tmp/afrr_delta_*.tar.zst

This extracts the Delta table to ~/tennet-afrr-data/delta/afrr_bid_ladder.

What Data Is Captured

Each ingestion run reads current + upcoming ladders and stores sampled snapshots.

Sampling by minutes-to-delivery (MTD):

• <180 min: every 15 minutes (0, 15, ..., 165)
• 180–719 min: every 60 minutes (180, 240, ..., 660)
• 720–1440 min: every 120 minutes (720, 840, ..., 1440)

This keeps dense coverage close to delivery and lighter coverage further out.

Delta Table Location

After extracting the archive:

• ~/tennet-afrr-data/delta/afrr_bid_ladder

Partitioned by isp_date (Amsterdam date of the ISP start, YYYY-MM-DD).

Schema

Each row is one bid ladder step for one ISP start at one snapshot time.

• isp_start_utc (timestamp): ISP start in UTC
• capacity_threshold (int16): ladder threshold
• price_down (float32): downward price level
• price_up (float32): upward price level
• snapshot_timestamp_utc (timestamp): when the snapshot was captured (UTC)
• minutes_to_delivery (int16): minutes from snapshot to ISP start
• isp_date (string): partition key — local date of the ISP start

Quick Example (Polars)

import polars as pl

df = (
    pl.scan_delta("~/tennet-afrr-data/delta/afrr_bid_ladder")
    .filter(pl.col("isp_date") == "2026-02-27")
    .sort(["isp_start_utc", "minutes_to_delivery", "capacity_threshold"])
    .collect()
)

All timestamps are UTC — convert to Europe/Amsterdam where needed.

Acknowledgements

Thanks to fboerman for tenneteu-py!