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Sources and methodology

Holgura mirrors two official publications. This page explains what we read, how we read it and what we count as a change.

Archived sources

Red Eléctrica de España (transmission network)

Every month, within the first five working days, REE publishes the demand and generation access capacity of every transmission node (CNMC Resolution of 1 December 2025). We archive the CSV and XLSX exactly as published.

CNMC (transmission and distribution)

Since April 2026 the CNMC publishes monthly maps with the capacity of every grid operator, per busbar of every substation above 1 kV (Circular 6/2025). We read the public layers behind those maps.

How we read them

  • Columns by header, never by position: REE changed its format three times in 2026 (61, 62 and 102 columns). If an essential column is missing the process stops and alerts us instead of inventing zeros.
  • No value is not zero: nodes without an agreed reference value appear as “no agreed value”, with the official reason.
  • Stable identity: a node keeps its code when REE renames it (same substation code and voltage).
  • Aggregated busbars: in distribution, unlabelled busbars of the same substation and voltage form one node. Available = its largest busbar; occupied = the sum.
  • Append-only history: each publication is stored as a new snapshot; earlier data is never overwritten or deleted.

What counts as a change

We compare each publication with the previous one from the same source, node by node, for demand, storage, generation and storage injection. ε = 0.5 MW; δ = 1 MW.

Liberatedfrom ≤ ε or no value to more than ε.
Saturatedfrom more than ε to ≤ ε.
Increaseavailable before and after, rises by at least δ.
Decreaseavailable before and after, falls by at least δ.
Withdrawna published value disappears.
Newthe node appears for the first time.

Attribution

Data source: Red Eléctrica de España (REE) and the Comisión Nacional de los Mercados y la Competencia (CNMC). Values are informative, do not add up across nodes and do not guarantee access: requests go to the relevant grid operator.