This archive goes back to 12 September 2017, which is when National Grid started forecasting and reporting carbon intensity. You can also see their current forecast. For carbon intensity data back to January 2015, calculated from Fuel Mix data, see the Fuel Mix Archive.
Wednesday 21st March 2018
Calculation by National Grid of the carbon intensity of GB electricity supply for the selected period (includes embedded generation and interconnector imports).
LOW: 215 ; AVERAGE: 323 ; HIGH: 396 CO2 g/kWh*
The carbon intensity data for this graph is National Grid half-hourly data for GB electricity, including embedded solar and wind generation, and interconnector imported electricity.
National Grid carbon intensity factors for each fuel source are slightly different from those used by electricity info elsewhere on the site.
The red and green zones in the Carbon Intensity chart represent the upper and lower quartiles for the half-hourly intensity data over the selected period.
A warning on white goods
If you intend using carbon intensity data to decide when to run white goods like washing machines and tumble dryers, please take note of Fire Service advice not to run such equipment at night or while unattended.