Gridstate presents observable system state from named public sources. It does not evaluate, recommend, or rank. This page defines how every value shown in the product is measured, so any figure can be traced back to its source and reproduced. Current source health is on the data status page.
Gridstate covers the 14 Distribution Network Operator (DNO) regions of Great Britain, matching the regions of the NESO Carbon Intensity API. A collection run executes every 15 minutes, checking for a newly published NESO interval; each run stores one timestamped reading per region when a new interval is available, so the historical record accumulates at half-hourly resolution, matching NESO’s own publishing cadence.
The percentage of half-hourly settlement periods in the trailing 48 hours (96 periods) in which at least one SO-flagged balancing acceptance was recorded for a generation unit attributed to the region.
Source: Elexon BMRS BOALF (Bid-Offer Acceptance Level Flagged) records, filtered to acceptances flagged as System Operator actions - the flag Elexon applies to actions taken for system (typically network-constraint) reasons rather than energy balancing. NESO applies the flag in real time to Balancing Mechanism Units it is using to manage a constraint on the transmission system, so these are transmission-level actions.
The network level and the geography are separate. Gridstate uses no distribution-network capacity or constraint data anywhere in its pipeline: the 14 DNO regions are the geographic frame these transmission-level figures are grouped into, not a claim about where the constraint sits. Balancing Mechanism Units are attributed to those regions through a curated BMU→region mapping. Coverage - the share of SO-flagged acceptances resolved to a region - varies by run, so it is measured on every run, stored with the reading, and shown live alongside the figures it supports rather than stated here as a fixed figure. Figures are indicative and pre-settlement.
The volume-weighted average price (£/MWh) of accepted SO-flagged constraint bids for the region over the trailing 48 hours, priced by matching Elexon BOD (Bid-Offer Data) to the accepted BOALF volumes. Negative values mean units were paid to reduce output.
This value has three distinct states, and the product never blurs them: a priced figure; no SO actions (a genuine zero - no constraint activity in the window); and data unavailable (the source could not be fetched - a gap, not a zero).
A genuine zero is only reported when the run can actually support it. Balancing actions that could not be attributed to a region are excluded from every region’s figures, so while mapping coverage for a run is degraded, a region with no attributed activity is reported as data unavailable rather than as a zero - the unattributed actions could belong to any region, and the product does not state a zero it cannot support.
Regional carbon intensity (gCO₂/kWh) and the generation fuel mix are NESO Carbon Intensity API regional estimates. Renewable share is the sum of the wind, solar, and hydro percentages of the mix. Biomass is deliberately excluded from the renewable share because its classification is contested; it remains visible in the full generation mix.
The 48-hour forward viewuses the same API’s published regional forecast. Forecast values are always labelled as forecasts. Where the product relates a forecast to history (for example, how often past readings matched a forecast renewable share), the statement describes the region’s own historical record - a stated frequency, not a prediction.
The day-ahead wholesale price from Elexon’s Market Index Data (N2EX, with APX fallback). Great Britain has a single national day-ahead price - there is no regionally traded day-ahead market - so the same figure is shown for every region. It is displayed for context alongside the regional indices, which is where regional variation appears.
The UK averageshown against any regional value is the unweighted mean of the 14 regional readings taken in the same collection run, stored alongside every reading. Deviations are expressed as plain arithmetic (“46% above the national average”), never as judgements.
Percentile: the share of a region’s own readings in the selected window (7/30/90 days) at or below the current value. Purely positional; shown only once the region has at least 48 hours of readings in the window. A window reflects however much history currently exists for the region, capped at the stated maximum - it does not pad or extrapolate short records.
Normal range: the mean ±1 standard deviation of the metric over the window (population formula). “Above/below normal range” states where the current reading sits relative to that band - it does not assess whether the position is good or bad.
Anomaly flags (saved regions): NEW HIGH/LOW IN WINDOW - the current reading exceeds every reading in the 7-day window; RAPID CHANGE 24H - constraint frequency moved more than 20 percentage points against the reading nearest 24 hours ago; DIVERGING FROM PEERS - constraint frequency differs from the mean of the other saved regions by more than 25 percentage points. Each flag is a statement of arithmetic fact.
Every reading stores the outcome of its collection run: ok (all sources fetched), partial (some failed), or gap. Charts draw missing data as gaps - never as zeros - and values from partial runs carry a caveat. The product prefers “Data unavailable” to a stale or interpolated number.
23 August 2026 - BMU mapping coverage corrected. The curated BMU→region mapping was extended to cover transmission-connected units that were previously unresolved: Staythorpe and Cottam Development Centre (East Midlands), Glendoe and five SSE hydro cascade schemes (North Scotland), and Kilmarnock South and Benbrack (South Scotland). Measured over the trailing 48 hours at the time of the change, coverage rose from 65.7% to 100%.
Regional constraint frequency and BM balancing cost figures from before and after this date are not directly comparable. Actions from the previously unresolved units were counted as unmapped and excluded from every region’s figures, so affected regions - East Midlands most of all - show a step increase in constraint frequency on this date. That step reflects improved attribution, not a change in grid conditions. Stored historical readings are left exactly as they were recorded: the product does not restate readings after the fact.
NESO Carbon Intensity API (CC BY 4.0) · Elexon BMRS BOALF/BOD/MID (free, account) · N2EX/APX via Elexon
Region boundaries: NESO GIS Boundaries for GB DNO Licence Areas. Supported by National Energy SO Open Data.
Gridstate presents third-party measured data. It does not provide investment advice.