Fuel Mix
Generation breakdown by source
What is it?
The Fuel Mix (or generation mix) shows what percentage of GB electricity comes from each source at any given time. It changes constantly based on weather, demand, and market conditions.
Understanding fuel mix is essential for ESG reporting, carbon calculations, and assessing grid decarbonization progress.
Key Points
Unit
Percentage (%) of total generation
Update Frequency
Every 5 minutes (real-time)
Source
National Grid ESO
Related
Carbon Intensity (derived from mix)
GB Fuel Sources
| Source | Typical Range | Notes |
|---|---|---|
Wind | 20-50% | Onshore and offshore combined |
Gas (CCGT) | 15-40% | Combined cycle gas turbines |
Nuclear | 12-18% | Baseload, fairly constant |
Solar | 0-15% | Varies by time of day and season |
Imports | 5-12% | From France, Netherlands, etc. |
Biomass | 4-8% | Including Drax wood pellets |
Hydro | 1-3% | Pumped storage and run-of-river |
Coal | 0-2% | Now rarely used, backup only |
Low Carbon vs Fossil
Low Carbon
- Wind (zero emissions)
- Solar (zero emissions)
- Nuclear (zero emissions)
- Hydro (zero emissions)
- Biomass (carbon neutral*)
*Biomass carbon accounting is debated
Fossil Fuels
- Gas CCGT (~400 gCO2/kWh)
- Gas OCGT (~500 gCO2/kWh)
- Coal (~900 gCO2/kWh)
Imports have mixed carbon intensity
Use Cases
ESG Dashboards
Display real-time and historical generation mix to show decarbonization progress. Calculate renewable percentage for sustainability reports.
Carbon Calculations
Fuel mix directly determines carbon intensity. When wind is high, carbon is low. Our API uses the official NESO carbon factors per fuel type.
Grid Monitoring
Track when renewables hit new records, or when the grid is stressed (high gas, low wind). Useful for trading and flexibility dispatch.
API Endpoint
GET /uk/carbon/fuelmix/currentReturns current generation percentages by fuel type.
{
"data": [{
"from": "2024-12-20T14:00Z",
"to": "2024-12-20T14:30Z",
"generationmix": [
{ "fuel": "wind", "perc": 35.2 },
{ "fuel": "gas", "perc": 28.5 },
{ "fuel": "nuclear", "perc": 15.1 },
{ "fuel": "solar", "perc": 8.3 },
{ "fuel": "imports", "perc": 6.8 },
{ "fuel": "biomass", "perc": 4.2 },
{ "fuel": "hydro", "perc": 1.5 },
{ "fuel": "coal", "perc": 0.4 }
]
}]
}