How to hit the Carbon Intensity (UK grid) API

National Grid ESO's Carbon Intensity API at https://api.carbonintensity.org.uk reports how much CO₂ the UK grid emits per kWh, with forecasts and the current fuel mix.

Authentication

None — no key, no signup. Every example runs as-is.

Full reference: https://carbon-intensity.github.io/api-definitions/

Current intensity

Actual and forecast gCO₂/kWh for this half hour.

curl https://api.carbonintensity.org.uk/intensity
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Example response (trimmed) 
{
  "data": [
    {
      "from": "2026-09-23T20:30Z",
      "to": "2026-09-23T21:00Z",
      "intensity": {
        "forecast": 175,
        "actual": 167,
        "index": "moderate"
      }
    }
  ]
}

Current generation mix

Percent from gas, wind, nuclear, solar…

curl https://api.carbonintensity.org.uk/generation
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Example response (trimmed) 
{
  "data": {
    "from": "2026-09-23T20:30Z",
    "to": "2026-09-23T21:00Z",
    "generationmix": [
      {
        "perc": 9.9,
        "fuel": "biomass"
      },
      {
        "perc": 0,
        "fuel": "coal"
      }
    ]
  }
}