What you're looking at
Every unit of electricity in Great Britain carries a carbon cost. When the wind is blowing and the sun is out, most of our power comes from renewables and that cost is low. When demand is high and gas plants fill the gap, it climbs. The light above shows that figure live, right now, straight from the National Energy System Operator — the body that runs the grid.
How to read it
- Green — the grid is clean. A good moment to run anything energy-hungry.
- Amber — middling. Fine, but not the greenest window.
- Red — carbon-heavy. If a task can wait, waiting saves emissions.
The two numbers
gCO₂/kWh is the grams of carbon dioxide released to make one kilowatt-hour of electricity. Lower is cleaner — it swings from roughly 50 on a windy night to 300+ on a still, cold evening. Renewables is the share of power coming from wind, solar, hydro and biomass at this moment.
Why we show it
The same kilowatt-hour can be two, three, even five times dirtier depending only on when it's used. Shifting flexible energy use — charging, laundry, batch jobs, manufacturing — into the green windows is one of the simplest ways to cut emissions without cutting anything else. We keep this on our page as a small, honest signal of when that matters.
Updates automatically every half hour. Source: National Energy System Operator.