# CE-NOTE-2026-04 data pack

Data behind *Where the Balancing Money Goes* (Compounding Energy, 14 October 2026).

## Files

| File | What it holds |
|---|---|
| `ce-note-2026-04_units_2025-26.csv` | Every BM unit paid in 2025/26: offers paid, bids paid to and by the unit, net, volumes, average prices, system-flagged shares, premium over the market index |
| `ce-note-2026-04_lead_parties_2025-26.csv` | The same, summed by Elexon lead party |
| `ce-note-2026-04_region_technology_2025-26.csv` | The same, by region and technology |
| `ce-note-2026-04_units_2026-27_H1.csv` | Units, April to September 2026 |
| `ce-note-2026-04_monthly_by_technology.csv` | Monthly, April 2025 to 11 October 2026, by technology |
| `ce-note-2026-04_monthly_neso_categories.csv` | NESO's balancing cost categories by month, £ million |

## Definitions

- **Offers paid**: Elexon indicative Period BM Unit Offer Cashflow, summed. Paid by the system to the unit for increasing output (or reducing demand).
- **Bids paid to unit**: positive Period BM Unit Bid Cashflow. The system paid the unit to reduce output. Typical for wind farms, whose bids are negative prices.
- **Bids paid by unit**: negative bid cashflow, sign reversed. The unit paid the system when told to reduce output, because it saved fuel. Typical for gas plants.
- **Net received** = offers paid + bid cashflow. **Gross received** = offers paid + bids paid to unit.
- **Volumes** are total accepted volumes (MWh). Bid volumes are negative.
- **Flagged** columns (`*_flagged`): the money and volume from acceptances NESO marked with the system flag (soFlag in BOALF), meaning it took them for a system reason such as a network constraint. Money is apportioned pro rata to flagged volume within each unit's half-hour.
- **Premium over market index**: offers paid minus the same volume valued at the Elexon APX market index price in the same half-hour. This is not profit; it ignores fuel, carbon and start-up costs.
- **Region**: transmission owner area from the NESO TEC register (SHET = North of Scotland, SPT = South of Scotland, NGET = England & Wales). Where the name match fails, transmission units are assigned by hand, mostly to a named TEC record; offshore wind farms connected through an offshore transmission owner take the onshore region of their landfall, and three batteries with no TEC record take their published site location. Embedded, supplier and aggregator units use their Elexon GSP group.

## Caveats

Indicative settlement data, before reconciliation runs. October 2026 rows in the monthly files are partial: Elexon data run to 11 October and NESO data to 6 October. Balancing Mechanism only: contracted services outside the BM are not attributed. Lead party is the BSC registrant, which may differ from the owner. Joint ventures are not apportioned.

## Licences

Contains BMRS data © Elexon Limited copyright and database right 2026, used under the [BMRS open data licence](https://www.elexon.co.uk/data/balancing-mechanism-reporting-agent/copyright-licence-bmrs-data/). Supported by National Energy SO Open Data. Derived tables © Compounding Energy Ltd 2026, free to reuse with attribution.