UK carbon intensity, live
Britain's electricity is producing 164 g of CO₂ per kWh right now, which counts as moderate. The cleanest stretch in the next day is 02:00 to 04:00.
Live data, updated .
Carbon intensity: how clean it is
gCO₂ per kWh, past and next 24h
Cleanest window ahead 02:00 to 04:00, around 68 g/kWh.
- Day-ahead forecast
- Actual
- Forecast
the numbers
under about 100 g counts as low, over 200 as high
More on carbon intensity →Generation mix: what is generating
last 24 hours, GW
the numbers
- Wind24%
- Solar7%
- Nuclear14%
- Gas39%
- Biomass9%
- Hydro2%
- Pumped storage0%
- Imports4%
- Other2%
solar and some wind sit on local networks with no live meter, so those two come from NESO's half-hourly estimate
More on the generation mix →The next 24 hours
- Cleanest: 02:00 to 04:00, averaging about 68 g/kWh.
- Dirtiest: 17:30 to 19:30, averaging about 183 g/kWh.
- Moving a dishwasher, washing machine or car charge into the cleanest window cuts its emissions, and on time-of-use tariffs it usually cuts the cost too.
Why it changes through the day
Carbon intensity follows the generation mix. When the wind picks up or the sun comes out, gas stations are turned down and intensity falls. In the early evening, when demand peaks and solar fades, more gas runs and it rises. Imports also matter: power from France is mostly nuclear and from Norway mostly hydro, while some other links carry more gas and coal power.
The Carbon Intensity API publishes a forecast as well as an estimate of actual intensity. Dashed lines on the chart show what was forecast; we also track how accurate the day-ahead forecast is.
Common questions
What is carbon intensity?
Carbon intensity is how much carbon dioxide is emitted to produce each kilowatt-hour of electricity, measured in grams of CO₂ per kWh. The more power comes from gas, the higher it is; the more from wind, solar, nuclear and hydro, the lower.
What is a good carbon intensity for the UK grid?
Lower is better. On very windy or sunny days Britain's grid can fall below 50 g/kWh; on cold, still evenings it can rise above 250. The Carbon Intensity API labels each reading from very low to very high, and those bands are tightened every year as the grid gets cleaner.
When is the greenest time to use electricity?
When wind and solar are strongest and demand is lower: often overnight on windy days and around midday on sunny ones. This page shows the cleanest stretch in the next day from the official forecast.
Where does this data come from?
From the Carbon Intensity API, run by NESO (the National Energy System Operator) with the University of Oxford and partners. It publishes a forecast for the next 48 hours and an estimate of actual intensity for each half-hour.