GB carbon-intensity forecast with greenest window API

Half-hourly GB grid carbon-intensity forecast for the day, reduced to the greenest and dirtiest windows and the daily average — a ready-made load-shifting decision. Answers 'when is the cleanest time to run my heat pump / charge tonight?'.

Price$0.01per request

MethodPOST

Route/v1/climate/uk-carbon-forecast

StatusLive

MIME typeapplication/json

Rate limit60/minute

Cache1800s public

climateenergycarbon-intensityforecastgridukgbdemand-responseload-shifting

API URLhttps://x402.hexl.dev/v1/climate/uk-carbon-forecast

Integration docs

Example request

{}

Example response

{
  "region": "Great Britain (national grid)",
  "horizon": "current calendar day, half-hourly",
  "count": 48,
  "averageGramsCO2PerKWh": 93,
  "greenest": {
    "from": "2026-06-05T03:00Z",
    "to": "2026-06-05T03:30Z",
    "gramsCO2PerKWh": 40,
    "index": "low"
  },
  "dirtiest": {
    "from": "2026-06-05T19:30Z",
    "to": "2026-06-05T20:00Z",
    "gramsCO2PerKWh": 187,
    "index": "high"
  }
}

Input schema

{
  "type": "object",
  "properties": {},
  "additionalProperties": false
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}