Data sources
Every figure comes from a public source. Live data comes straight from Elexon, NESO and Octopus Energy, and from the Carbon Intensity API mostly through our own server, which keeps a short-lived copy.
Where each figure comes from
Dots mark the pages each source feeds; strips show how often live sources update.
| Source | Across a day | Dashboard | Green Signal | Regions | History | Records | Grid costs | Agile | Price cap | Bill | Net zero |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Carbon Intensity APIEvery 30 minutes | Not used | Not used | Not used | Not used | |||||||
| Elexon BMRS: FUELINSTEvery 5 minutes | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Elexon BMRS: system frequencyEvery 15 seconds | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Elexon BMRS: FUELHHEvery 30 minutes | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Elexon BMRS: INDO and ITSDOEvery 30 minutes | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||||
| NESO demand data updateForecasts each half hour, actuals a few times a day | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Elexon BMRS: WINDFORSeveral runs a day | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| NESO embedded wind and solar forecastSeveral runs a day | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Octopus Energy APIDaily, around 16:00 | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| NESO balancing costs and constraint breakdownDaily, a few days in arrears | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Heating oil pricesBy hand: monthly | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |
| Energy price cap by regionBy hand: quarterly | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | ||
| Energy price capBy hand: quarterly | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |||
| UK greenhouse gas emissions statisticsBy hand: final each February, provisional each spring | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |
| Energy TrendsBy hand: quarterly | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |
| Carbon budget statementsBy hand: annual | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |
| CO₂ and greenhouse gas emissionsBy hand: annual | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |
| Greenhouse gas conversion factorsBy hand: annual | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | |
| GIS boundaries for GB DNO licence areasBy hand: as areas change (2024 edition) | – | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used | Not used |
Fetched liveMaintained by hand
Live
Fetched while you browse.
- Carbon Intensity API
NESO, with the University of Oxford, EDF Europe and WWF
Generation mix shares, national and regional carbon intensity, emission factors, postcode lookup, and the half-hourly forecast behind the ribbon, Green Signal and the region map. Most requests go through our own server, which keeps a short-lived copy so the API is not asked the same question by every visitor.
Every 30 minutes
- Elexon BMRS: FUELINST
Elexon
Instantaneous generation by fuel in megawatts, used for GW figures, pumped storage and interconnector flows.
Every 5 minutes
Grid frequency, read every 15 seconds, for the frequency trace on the dashboard.
Every 15 seconds
- Elexon BMRS: FUELHH
Elexon
Half-hourly metered generation by fuel for the history page.
Every 30 minutes
- Elexon BMRS: INDO and ITSDO
Elexon
National and transmission demand outturn; its half-hourly shape stands in for a household in the tariff replay.
Every 30 minutes
- NESO demand data update
National Energy System Operator
Embedded wind and solar for the current half hour, added to metered generation for the national total and the power flow. Forecast until actuals are published.
Forecasts each half hour, actuals a few times a day
- Elexon BMRS: WINDFOR
Elexon
Forecast output of transmission-connected wind farms, for the 48-hour wind and solar forecast.
Several runs a day
- NESO embedded wind and solar forecast
National Energy System Operator
Forecast output of wind and solar on local networks, which is almost all British solar.
Several runs a day
- Octopus Energy API
Octopus Energy
Agile Octopus half-hourly unit rates for all 14 regions, and Agile, Go, Tracker and Flexible rates with standing charges for the 28-day tariff replay.
Daily, around 16:00
- NESO balancing costs and constraint breakdown
National Energy System Operator
Daily balancing costs by settlement period, and the generation turned down for thermal constraints.
Daily, a few days in arrears
Reference
Updated here by hand when published. Each page states its period. The emissions, budgets and shares below make up the net zero tracker.
- Heating oil prices
BoilerJuice
The UK average price for a 1,000 litre order, used as the starting price in the bill calculator. Copied by hand with its date.
Monthly
Regional unit rates and standing charges by payment method for the bill calculator and the Agile comparison.
Quarterly
- Energy price cap
Ofgem
Unit rates, standing charges and typical bills since 2019, for the price tracker, Agile comparison and bill calculator.
Quarterly
Emissions from 1990 and by sector (2025 provisional).
Final each February, provisional each spring
- Energy Trends
DESNZ
Renewable and coal shares of generation.
Quarterly
- Carbon budget statements
DESNZ and the Climate Change Committee
Carbon budget caps and outturns.
Annual
- CO₂ and greenhouse gas emissions
Our World in Data and Global Carbon Project
International comparison on the net zero page.
Annual
Gas and heating oil emission factors in the bill calculator.
Annual
The outlines of the 14 network areas on the region map.
As areas change (2024 edition)
Methods and corrections
How each answer is worked out, when each hand-kept figure was last checked against its source, and every correction we have made.
How we get the numbersOfficial reports
The papers behind the numbers: NESO’s outlooks, Ofgem’s decisions and the government’s statistics, each with a one-line summary.
Browse the official reports