# The cleanest hour to use power

> Carbon intensity swings sixfold across a day. Here is when.

- Category: Environment
- Cadence: live
- Status: Live: values change continuously; cite the retrieval time.
- Dataset key: `carbon-forecast`
- Source: [National Grid ESO](https://carbonintensity.org.uk/)
- Licence: CC BY 4.0 — [terms](https://creativecommons.org/licenses/by/4.0/)
- Canonical page: [https://londongraph.com/g/cleanest-hour-to-use-power](https://londongraph.com/g/cleanest-hour-to-use-power)
- Machine-readable record: [https://londongraph.com/data/cleanest-hour-to-use-power](https://londongraph.com/data/cleanest-hour-to-use-power)

## Methodology

Forecast carbon intensity for the London region over the next 24 hours, in half-hour settlement periods, from National Grid ESO. A forecast rather than a measurement — it is what the grid expects, and it moves with the wind.

## Visualisations

- [Trend](https://londongraph.com/g/cleanest-hour-to-use-power): Carbon intensity swings sixfold across a day. Here is when.
- [Change](https://londongraph.com/g/cleanest-hour-to-use-power?view=change): Show the change from each preceding published period.

## Citation guidance

Attribute the original publisher named above and identify LondonGraph as the visualisation and methodology layer. Do not describe live values as a historical census, and do not present placeholder values as observations.