National Energy System Operator (NESO)
Grid Carbon Intensity (GB Electricity)
How much CO2 every unit of electricity on the GB grid carries, right now and forecast ahead — nationally, by region, and by the first part of a postcode. Plus what is actually generating it: wind, gas, nuclear, solar and the rest.
At a glance
- Publisher
- National Energy System Operator (NESO)
- Licence
- Creative Commons Attribution 4.0 — Not OGL. Attribution is required, and NESO layers extra terms on top — notably no reselling the API and no using it to replace their own service. · what this means
- Updates
- Real-time
- Cost
- Free — open data
- Last checked
- 2026-07-16
EnergyLogisticsFacilities managementManufacturing & industryEnergy & environment
What your business can use it for
- ESG reportingPut a defensible number on the emissions of the electricity you actually used, half-hour by half-hour, from the official GB source — rather than applying one flat annual average to the whole year.
- Energy & carbon managementShift what you can move — EV charging, refrigeration, plant, batteries — into the hours when the grid is cleanest, using the forecast rather than guesswork.
Works with data you already have
- The postcodes of your sitesPostcodesThe postcode endpoint takes the OUTWARD code only (the first half, e.g. RG41) — not a full postcode
How to get it
- Carbon Intensity API — no key, no accountAPIFree and unauthenticated. Data is organised in half-hour settlement periods, all timestamps UTC.
- API documentation — every endpointAPICovers current, historic and forward-looking intensity, the generation mix, and the emissions factors per fuel.
What's involved in using it
- The data comes in half-hourly snapshots, so to build any history you have to keep pulling it on a schedule and stitch thousands of small readings together — it isn't one file you download once.
- It only recognises the first half of a postcode (the outward code), so it can tell you the carbon level for a broad grid region but not for your specific street; two sites in the same town get the same figure.
- It's an estimate for the grid, refreshed constantly and offered with no guarantees, so it's fine for reporting and planning but shouldn't sit on the critical path of anything you bill a customer for.
The technical detail, for whoever sets it up (5)
- Great Britain only — Northern Ireland is on a separate grid and is not covered.
- The regional and generation-mix endpoints are labelled beta by the publisher.
- The forward-looking endpoints run to 48 hours ahead. NESO's own marketing describes a model forecasting further out than that; the two claims are not reconciled anywhere public, so build against the 48-hour endpoints.
- It is an estimate for the grid, not a meter reading for your building — it tells you the carbon per unit, not how many units you used.
- Provided as-is: NESO explicitly disclaims accuracy and may change or withdraw the API without notice.
Ask us about Grid Carbon Intensity (GB Electricity)
Ask a factual question about Grid Carbon Intensity (GB Electricity) — what it covers, how often it changes, whether it matches the records you keep — and we will answer, free. Or tell us what you are trying to work out, and we will tell you what it would take to get this data working next to the numbers you already have.