Data Dictionary

Both maps are keyed by the §1a zone codes. All 11 zones price in EUR; the payload carries no per-zone currency or unit fields.

GB is not part of this endpoint: ENTSO-E's A44 series carries nothing for GB. The GB day-ahead auction curve is served by /v1/history/n2ex-dayahead (§04a, GBP/MWh); the terminal's GB price tile reads the Elexon Market Index internally.

The payload is this one map. Nameplate capacities, direction labels and utilisation are not part of it; §2a below is the reference for reading each id's sign.

History request conventions — from / to are UTC ISO dates (YYYY-MM-DD), window capped at 3 years. When real coverage starts later than from, the payload declares it via oldestAvailable instead of silently returning a shorter series. An as_of instant (Specification §06) returns §4, §4a, §11 and §12 as captured at that instant and adds pointInTime; a window with nothing captured by then comes back live:false with an empty series and one of the two as_of reasons in §27. §5 and §13 refuse as_of.

GB is §4's honest gap: ENTSO-E's A44 series carries nothing for GB, so the real GB auction curve comes from the Nord Pool N2EX data portal instead. Anonymous portal access backfills only ~2 months; depth past that accrues one day at a time from the live worker fetch. Same envelope and meta conventions as §4 (completeness, gaps, dataAgeSeconds, dataAsOf); window capped at 3 years. Paused since 24 September 2026 while Nord Pool confirms redistribution rights: the endpoint answers 451 (see the note on paused datasets under the lede).

A derived measure computed from §4's settled series, not a vendor-provided one — no free options data exists for EU power. Never annualized; log returns are deliberately not used because EU day-ahead prices go negative.

live is true only when capacity, derates and demand are all real for the requested country. Derate collection covers all eight countries (DE, FR, ES, IT, NL, NO, SE, PL); a zone the collector has not asked about is never presented as "zero MW unavailable" — the response falls back instead.

Degree-day base: 18°C (EU) / 65°F (US) by default. An optional base query parameter (°C, clamped 5–30) re-bases both HDD and CDD for the request; the base joins the server-side cache key, so different bases never share a cached value.

Deliberately no five-year band here: LNG send-out is driven by spot-arbitrage economics, not the repeatable seasonal shape underground storage has — a min/max/avg band would overclaim a "normal range".

EEX primary auction reports (public.eex-group.com), under EEX's written permission of 29 July 2026, which covers primary auction data only: no EUA spot or futures price is served, and an auction clearing price is not one. Aviation allowance (EUAA) auctions are not ingested. Read once a day after the 09:00 to 11:00 CET auction window. Attribution: Source: EEX.

§14–25 document the constraint & event layer — the endpoints behind the dislocation widgets. None of these carries a simulated fallback: when an upstream has nothing, the envelope says so (live:false + reason) rather than inventing a value. An empty constraint radar is information; a fake binding constraint is not.

Point-in-time capture. REMIT UMMs §19 and unit outages §20 are version-captured since 2026-07-14: every republished version our polls have seen is retained with the publisher's own timestamp. Redispatch measures §16 and GB balancing acceptances §17a are version-captured from the date /coverage shows for each of those two series, shown there even before either one holds an actual revision: every change our re-reads have seen to what the source states is retained as a later version, dated to when we captured it, since neither source gives its own publication time for a correction, so none is invented. For a GB balancing acceptance the versions follow Elexon's acceptance (BOALF) itself: the unit, acceptance number and segment start identify it, and a change to its level from or level to, segment end, national grid unit name, closing settlement period or SO, STOR or RR flag is a version. Its side and matched offer or bid price are Voltstack's own match against Elexon's bid-offer data (BOD), not part of the acceptance: they never make a version, and when better BOD data arrives they are corrected in place on the latest version, which keeps the time it was captured. Version 1 of a redispatch measure carries the measure's own window start as published_at; version 1 of a GB balancing acceptance carries Elexon's own acceptance time. Only a later version of either is dated to when we captured it. An append-only vintage sidecar records the four forecast feeds (§10 weather, §23 forecast risk, the GB NESO forecast behind §17a, the FR RTE forecast) at every capture pass since 2026-07-31, and the JAO domains behind §18 whenever a value changes. It also records the day-ahead prices behind §1, §4 and §4a, imbalance prices §14, the AEP estimator §15, NRV §16, generation §3, load, storage §7 and §11, LNG §8 and §12, and cross-border flows §2: once when a value is first captured and again whenever it changes, never on an identical re-fetch. Capture runs forward from each series' own start and is never backfilled. as_of on §4, §4a, §11 and §12 reads it.

EU areas come from ENTSO-E A85 queried per control area. Where an area still runs dual-direction pricing (e.g. FR publishes A04 excess and A05 deficit series), the deficit price is surfaced as "the" imbalance price — the number that prices a short position. The four German control areas never publish A85 to ENTSO-E at all (verified empirically); their rows come from the netztransparenz.de AEP estimator. Since 24 September 2026 those four rows are withheld from this endpoint: each is absent from areas and reads paused in meta.areaStatus, and meta.upstream names ENTSO-E alone. When ENTSO-E returns no price for any of its five areas, nothing is left to serve: the endpoint answers live: false with reason upstream-error (§27) and data: null, and any German rows it withheld still read paused in meta.areaStatus.

Germany settles imbalance with one uniform price across all four control areas (reBAP), published on the TSOs' shared portal netztransparenz.de — not on ENTSO-E. The estimator is near-real-time; the quality-assured settled series follows with a ~2–3 week settlement lag. The settled cross-border marginal price and the TSOs' scarcity flag are in §17. Settled archive from 2022.

Redispatch is the grid stress zonal prices hide: DE_LU clears as one zone while the TSOs pay to move generation around the internal north–south constraint. Event archive from 2024-07 (~42 TWh of measures), extended continuously.

The scarcity flag is the TSOs' own published column, not a derived heuristic — 18 flagged quarter-hours in 4.5 years of history make it a genuine rare-event regime marker (most recent real episode: 2026-04-06, reBAP −6,642.76 EUR/MWh). Pairs with §16: that section shows the TSOs physically moving generation; this one shows the price the balancing market paid.

Sources: Elexon Insights (BOD/BOALF/MID, event-grain acceptances) and the NESO Data Portal. The balancing-mechanism acceptance stream is stored event-by-event and exportable in bulk. The accepted offer and bid prices stored per settlement period (bm_accepted_offer_price_GB and bm_accepted_bid_price_GB in the export) weight each acceptance segment by the MWh it delivers inside the period, so a segment spanning two periods counts in both, and a side whose segments deliver no energy there has no value (Methodology Guide §04). Acceptance segments for a day's last periods that are made after its last pass and end by midnight are not captured. A day's last periods are numbered 45 and 46 on the 46-period day when the clocks go forward in March and 49 and 50 on the 50-period day when they go back in October, and every day starts at period 1. Before the date /coverage shows for GB balancing acceptances, a segment was weighted by its level, one spanning two periods weighed twice in the period it starts, and a day's last periods also took in the day before's segments that ran past midnight, which moved topOfStackOffer, topOfStackBid and bmMidSpread there too. Those segments went by period number, so on the day after the March change they landed in periods 45 and 46 and on the October change day in periods 47 and 48, not its last periods, while on the March change day and the day after the October change, which have no periods with those numbers, they were left unpriced. Values stored before that date may be restated by a repair.

MaxBex archive: 365-day backfill (~1.3M rows), extended daily from the JAO Publication Tool — where the Core flow-based grid actually binds, border by border. The Nordic flow-based domain (MaxBex, net positions) is ingested to the same store under identical conventions; a served Nordic radar follows demand. Both domains, bulk extracts included, are paused since 24 September 2026 while JAO confirms redistribution rights.

Messages are versioned as republished; the latest version wins and cancelled/outdated messages drop out. Upstream: Nord Pool REMIT UMM.

Derived from ENTSO-E A77/A80 unit outage filings: fleet nominal minus the day's deepest active outage per unit, summed across units — a forward curve that rebuilds on every outage revision.

RTE Generation Forecast API (data.rte-france.com), read into the store about every 4 hours. The window runs from 24 h before the request to 4 days after it. Every value is RTE's own, unchanged; the load factor RTE also publishes is not stored. A requested horizon with no rows, while other horizons have some, is echoed with an empty points array, never replaced by another; when the production type has no rows in the window at all, the answer is live:false with data:null and a reason. RTE publishes the purchase-obligation aggregate run by run, and every horizon served for it is one run, value for value; a horizon without a run asked of it is echoed with an empty points array, since no single RTE series answers it. The aggregate rows stored before v1.24 kept, for each interval, whichever run RTE listed last under its horizon, without the run's label, and under D-1 and ID that mixed several runs. They are served nowhere, neither here nor in the CSV export nor as recorded revisions; each run's history starts with the first read that stored it. Attribution: Source: RTE (data.rte-france.com).

NVE Magasinstatistikk, weekly cadence, history from 1995 — thirty years of the structural driver behind Nordic and German power.

National Gas Transmission Data Portal (open data policy). GB-only for flows by design: no Norwegian flow, linepack or nomination figure appears here or anywhere on this surface. Norwegian field and terminal unavailability events are a separate endpoint, §22a.

Source: Gassco (umm.gassco.no). ACER REMIT gas urgent market messages read from the UMM Atom feed at request time; the REMIT vocabulary (eventStatus, eventType, unavailabilityType) is carried verbatim, not mapped. Events only: Norwegian pipeline flows are not ingested here or anywhere on this surface. The aggregated exit nominations Gassco also publishes are stored for the Voltstack workspace since 24 September 2026 and appear in no payload on this surface. Fetched on a 15 minute TTL. When the upstream does not answer, a retained copy up to 24 hours old is served with lastGood:true and its original asOfMs; while such a copy exists a rate-limited upstream and a failed one produce the same envelope, and reason (rate-limited or upstream-error) appears only when no copy exists. meta.unit lists the units the payload carried, or n/a for an empty feed; meta.areaStatus.ummEvents is a constant live and carries no freshness information. Gassco publishes the data under its UMM Terms and Conditions and its Principles for Publication, both on umm.gassco.no.

Forecast vintages cannot be backfilled, so this series is vintage-native by construction: the band grows one day at a time, and a young series reports its real day count instead of a fabricated percentile.

Arbitrage is an exact perfect-foresight optimization on settled DE_LU day-ahead prices — an upper bound, and labeled as one. Capacity legs settle at pay-as-cleared prices from regelleistung.net. Full methodology and assumption table are published with the benchmark.

A nightly harness reconciles the settled day-ahead archive against Bundesnetzagentur SMARD (CC BY 4.0) — an independent reference — for every zone SMARD also publishes, plus Fraunhofer ISE Energy-Charts for DE_LU as a pipeline check: Energy-Charts' price endpoint is itself SMARD-sourced (per its own license_info), so that comparison validates our plumbing rather than adding source independence. Restatement risk is measured daily, not assumed away. This endpoint returns a plain payload, not the standard envelope.

Live coverage as at 2026-07-31. Exchange-licensed forward and spot domains (EUA/UKA spot & futures, TTF/NBP gas curves, Brent/WTI oil) follow the same field conventions and are documented per-tenant on entitlement; EEX EUA primary-auction results are live and documented in §13b.
v1.24 · 2026-10-25: §20a's horizon names RTE's run for the purchase-obligation aggregate (D-1/DA02, ID/ID07), so every horizon served for it is one RTE run; before, several runs were stored under one horizon and the last one RTE listed kept for each interval. availableHorizons lists the aggregate's runs, and its rows stored before this revision are served nowhere. §26's rte row says so. Wind and solar are unchanged, and no other field, type or unit changed. v1.23 · 2026-10-25: §13b and §26's eex-eua-auction row name the attribution as Source: EEX, the line the platform shows beside the same data; Source: EEX Group belongs to the EEX DataSource data a desk brings itself. §26's rte row names RTE's purchase-obligation aggregate. No field, type or unit changed. v1.22 · 2026-10-23: new §13b documents /v1/carbon/eua-auctions, EEX's EUA primary auction results, and new §20a documents /v1/power/fr-generation-forecast, RTE's French generation forecast. §26's eex-eua-auction and rte rows point to them and name the attribution each carries; the rte row no longer says its /v1 path follows. No other field, type or unit changed. v1.21 · 2026-10-01: Publisher details: Voltstack Limited, Dublin, Ireland. No field, type or unit changed. v1.20 · 2026-09-28: the point-in-time capture note under §14's lede no longer says redispatch §16 and GB balancing §17a are version-captured with a publication timestamp since 2026-07-14, since neither source gives one. It points each at the date /coverage shows for it, says what version 1 of each carries as published_at (the measure's own window start, or Elexon's own acceptance time), and says which fields of a GB acceptance make a version and that its matched price and side are corrected in place. REMIT UMMs §19 and unit outages §20 are unchanged. §17a's note states how the accepted offer and bid prices are now weighted (each acceptance segment by the MWh it delivers inside each period), that acceptance segments for a day's last periods made after its last pass that end by midnight are not captured, how the last periods are numbered on the two clock-change days, that values before the date /coverage shows weighted a segment by its level, counted one spanning two periods twice and took in the day before's segments that ran past midnight, by period number, and that a repair may restate them. §17a's rows now name what the endpoint serves: bmMidSpread as topOfStackOffer minus midLatest (it read "accepted offer/bid spread vs the market index"), topOfStackBid as the highest matched bid (it read "lowest accepted bid price"), both top-of-stack prices as maxima rather than the energy-weighted averages, midLatest and the wind figures at bmMidSpreadAt and windDeltaAt, which gets its own row, and how topUnits' figures are made. The endpoint's fields, types and units are unchanged; the rows now give bmMidSpreadAt as string or null, and topUnits' units. The values of those series, and §17a's top-of-stack prices and spread in each day's last periods (on the day after the March change also in periods 45 and 46, and on the October change day in periods 47 and 48), changed from that date. v1.19 · 2026-09-27: §22a's note and both Gassco rows in §26 name the Gassco UMM Terms and Conditions and the Principles for Publication, both on umm.gassco.no. No field, type or unit changed. v1.18 · 2026-09-24: §14's note covers a response in which ENTSO-E returns no price for any of its five areas. Nothing is then left to serve, so the endpoint answers live false with reason upstream-error and data null, and any German rows it withheld still read paused in meta.areaStatus. It could previously come back live with an empty areas map. The reason value is the one §27 already lists. No field, type or unit changed. v1.17 · 2026-09-24: §22a no longer says the Gassco nominations are not ingested. Gassco confirmed on 15 September that they are covered, and Voltstack now stores its aggregated daily exit nominations for the workspace; they appear in no payload on this surface, and Norwegian pipeline flows are still not ingested. §26 gains the gassco-nominations source. No field, type or unit changed. v1.16 · 2026-09-24: a new note under the lede states the redistribution pause ruled on this date: §4a, §15, §16, §17 and §18 answer 451 with error "unavailable" while their publishers (Nord Pool N2EX, netztransparenz.de, JAO) confirm redistribution rights, and each carries a PAUSED mark. §14 keeps its ENTSO-E areas and withholds the four German rows, and its areaStatus vocabulary gains paused. The Access note says a key reaches full depth only on an endpoint that is not paused. §18 and §26 say the bulk extracts of the JAO domains are paused too, and §26 marks the jao-constraints, netztransparenz and n2ex-dayahead sources. No field, type or unit changed. v1.15 · 2026-09-23: §4, §4a, §11 and §12 gain pointInTime, present only on an as_of read; §11's is for the requested area, and its five-year band is null on that read. §27's reason enum gains as-of-nothing-captured and as-of-only-implausible, the 200 live:false answers for a window with nothing to serve as of the instant. The history conventions note says which endpoints answer as_of and which refuse it. The point-in-time note under §14 lists the price and fundamentals series now captured on change and no longer says the as-of API is outside the /v1 surface. No existing field, type or unit changed. v1.14 · 2026-09-23: the envelope note gains meta.dataAsOf, the newest data point behind a payload's headline values, which /status now ages each feed from; §04a names it; §09 gains points[].gasDay. v1.13 · 2026-09-23: §11 gains the optional area parameter: each of five EU countries is banded against its own prior years, and GIE_UK is refused because its series changed basis on 2020-12-30. v1.12 · 2026-09-22: the Access note described a surface that refused every request carrying no key, measured 9 August 2026. Production now answers such a request as a labelled sample, measured 22 September 2026, and the note says so in step with Specification v1.10 §03. No field, unit or endpoint changed. v1.11 · 2026-09-18: §07 gains countries[].basis; the UK storage series is re-keyed to AGSI+'s Post-Brexit dataset (GB*) and declared estimated and partial. v1.10 · 2026-09-13: new §22a documents /v1/gas/norway-events, the Gassco REMIT UMM events feed live since 13 September 2026, field by field: the per-message capacity unit and why there is no feed-level total, asOfMs as the evaluation instant the counts travel with, balancingZones as raw EIC codes with no name map, REMIT vocabulary verbatim, the empty feed as a real reading, the 15 minute TTL and 24 hour retained copy, and the caveat that events[] can carry a superseded message beside its revision so aggregation belongs on activeNowUnavailable. §22's note no longer says the Norwegian half is parked: that endpoint is GB-only for flows and points at §22a. §26 gains gassco. The header version line, which v1.9 left reading 1.8, is corrected. No existing field, type or unit changed. v1.9 · 2026-09-08: §26's entsoe row records the File Library extracts as the persisted fallback for prices, load, generation, imbalance and cross-border flows. Recorded here retrospectively; that revision shipped without a history line. No field, type or unit changed. v1.8 · 2026-08-27: §27's reason enum gains bad-request, returned with a 4xx when the caller's own parameters are invalid (an unknown feed or series, a malformed instant or window) so a keyed client can tell a request mistake from an outage; previously such requests answered 200 upstream-error, indistinguishable from a capture-pipeline failure. First served by the point-in-time vintages endpoint. No field, type or unit changed. v1.7 · 2026-08-27: the access note records the key gate's second refusal: keys are scoped by endpoint family (history, current, all), and a valid key presented on an endpoint outside its scopes is refused 403 insufficient-scope. Documentation catch-up to the shipped gate; Specification §03/§08 remains the authority on the access model. No field, type or unit changed. v1.6 · 2026-08-09: §24 no longer describes its endpoint as "public, no auth", which was false against the shipped gate, measured 401 unkeyed on every documented /v1 path. The key gate is now stated once, for the surface, in the access note under the lede, and no section carries a per-endpoint key rule; that note also records the one endpoint carrying a plan requirement beyond the key gate, which is where this dictionary and Specification §06 have to agree. §25's "public" attaches explicitly to the /status page. No field, type or unit changed. v1.5 · 2026-08-08: §7's storage country list and §27's weather region ids each gain the one id that was being served and had never been documented. No field, type or unit changed. v1.4 · 2026-07-31: document version and date published as machine-readable meta tags (voltstack-doc-version, voltstack-doc-updated) and printed in the page header; the PDF edition is served alongside the HTML at /docs/. v1.3 — 2026-07-31: §1/§2 corrected to the served map shapes (GB pointer moved to §04a); phantom commodities-benchmarks path removed from §13; §10 degree-day base parameter documented; §25 cross-validation independence phrasing corrected; §26 gains eex-eua-auction and rte; §27 reason enum corrected; envelope note gains lastGood and areaStatus; point-in-time capture note added to §14–25. © 2026 Voltstack Limited.