Enter how many kilowatt-hours of electricity you use and the grid's carbon intensity, and this works out the carbon emissions. The UK grid average is around 207g of CO2 per kWh and falling as more renewables come online.
Grid carbon intensity is the average CO2 emitted per unit of electricity, and it changes hour by hour as the mix of wind, solar, gas and nuclear shifts. The yearly UK average is roughly 207g per kWh, but on a windy night it can fall below 50g and on a cold still evening climb well above 300g, which is the idea behind shifting heavy use to greener hours. Using less in the first place is covered across the electricity guides; to turn the same kWh into money, use the kWh to cost calculator.
Common questions
How much CO2 does 1 kWh of electricity produce?
On the UK grid average of about 207g per kWh, one kWh produces roughly 0.21 kg of CO2. The exact figure depends on what is generating power at the time, from under 50g on a windy night to over 300g at peak.
Is electricity getting cleaner?
Yes. The grid's average carbon intensity has fallen sharply over the past decade as coal closed and wind and solar grew, so the CO2 per kWh today is a fraction of what it was, and it continues to drop.