Electricity Grid Review 2025: Great Britain
January 1 - December 31, 2024 vs 2025
Data coverage: 366 days (2024), 365 days (2025)
1. Electricity Price (Day-Ahead, GBP/MWh)
Correlation coefficient: -0.67 (2024), -0.68 (2025). Strong negative correlation - higher renewable generation = lower prices, reflecting the merit order effect.
1.1 Daily Price Extremes
Based on daily average prices
| Metric | 2024 | 2025 |
|---|---|---|
| Highest Daily Avg | £236.8 (Dec 12, 2024) | £282.8 (Jan 22, 2025) |
| Lowest Daily Avg | £7.3 (Apr 06, 2024) | £1.4 (Oct 04, 2025) |
| Negative Price Days | 0 | 0 |
| Negative Price Hours | 141 | 190 |
1.2 Hourly Price Extremes
| Metric | 2024 | 2025 |
|---|---|---|
| Highest Price | £491.0 (Dec 12, 2024 16:00) | £958.5 (Jan 22, 2025 17:00) |
| Lowest Price | £-28.2 (Apr 13, 2024 13:00) | £-30.5 (May 25, 2025 11:00) |
1.3 Days by Price Range
Based on daily average prices
| Range (£/MWh) | 2024 | 2025 | Δ |
|---|---|---|---|
| £0-50 | 33 | 33 | 0 |
| £51-100 | 304 | 276 | -28 |
| £101-150 | 26 | 51 | +25 |
| £151-200 | 2 | 2 | 0 |
| £201+ | 1 | 3 | +2 |
1.4 Hours by Price Range
Based on hourly prices
| Range (£/MWh) | 2024 | 2025 | Δ |
|---|---|---|---|
| Negative | 141 | 190 | +49 |
| £0-50 | 1,152 | 869 | -283 |
| £51-100 | 6,548 | 5,926 | -622 |
| £101-150 | 870 | 1,600 | +730 |
| £151-200 | 40 | 75 | +35 |
| £201+ | 31 | 47 | +16 |
1.5 Average Price by Hour of Day
1.6 Price Distribution (Hourly)
190 hours with negative prices across 33 days. Most negative: £-30.5/MWh.
Average daily price swing: £68/MWh. Maximum single-day swing was £866/MWh on 2025-01-22 (low: £92, high: £958).
Notable monthly evolutions
Change: +72% vs 2024
1.7 Multi-Level Price Heatmap
Price Heatmap
£/MWh
hourly range: -31-959
Yearly
Monthly
Daily
Hourly
2. Load
2.1 Monthly Load
2.2 Average Load by Hour of Day
Peak demand at 17:00 (36.5 GW). Minimum at 04:00 (23.0 GW).
2.3 Weekday vs Weekend
2.4 Net Load Pattern (Duck Curve)
Evening ramp of 9.7 GW from belly (04:00) to evening peak (18:00). This requires flexible dispatchable generation or storage to meet rapidly increasing demand as solar output decreases.
2.5 Seasonal Net Load Patterns
The duck curve shape varies significantly by season due to changes in solar intensity and heating/cooling demand patterns.
Winter (Dec-Feb)
Belly: 15.1 GW @ 04:00 | Peak: 28.8 GW @ 17:00 | Ramp: 13.7 GW
Spring (Mar-May)
Belly: 15.3 GW @ 03:00 | Peak: 23.7 GW @ 19:00 | Ramp: 8.5 GW
Summer (Jun-Aug)
Belly: 13.7 GW @ 13:00 | Peak: 20.7 GW @ 19:00 | Ramp: 6.9 GW
Fall (Sep-Nov)
Belly: 12.4 GW @ 03:00 | Peak: 23.1 GW @ 17:00 | Ramp: 10.7 GW
Winter shows a more pronounced duck curve with an evening ramp of 13.7 GW, 6.8 GW larger than summer (6.9 GW). This may reflect higher evening demand from heating and lighting.
2.6 Peak & Minimum Demand Records (2025)
| Rank | Highest Load | Date | Lowest Load | Date |
|---|---|---|---|---|
| 1 | 49.1 GW | 2025-01-09 17:00 | 16.6 GW | 2025-08-24 04:00 |
| 2 | 48.2 GW | 2025-01-10 11:00 | 16.8 GW | 2025-08-24 05:00 |
| 3 | 48.1 GW | 2025-01-10 10:00 | 17.0 GW | 2025-08-24 03:00 |
3. Production-Based vs Flow-Traced Carbon Intensity (gCO₂eq/kWh)
Production-based carbon intensity is 17.1g higher than flow-traced carbon intensity in 2024 (20.3g in 2025). This means Great Britain's imports are cleaner than domestic production, lowering the carbon footprint of consumed electricity.
3.1 Monthly Production Mix
3.2 Production Mix (Domestic Generation)
3.3 Flow-Traced Power Mix
3.5 Power Mix Comparison
Production vs Flow-Traced consumption by source
| Source | Prod 2024 | Flow-traced 2024 | Prod 2025 | Flow-traced 2025 |
|---|---|---|---|---|
| Wind | 35.4% | 32.3% | 35.8% (+0.4pp) | 32.6% (+0.3pp) |
| Gas | 31.2% | 27.5% | 32.3% (+1.1pp) | 28.2% (+0.7pp) |
| Nuclear | 16.4% | 19.7% | 14.2% (-2.2pp) | 18.1% (-1.6pp) |
| Solar | 6.8% | 6.8% | 7.8% (+1.0pp) | 8.2% (+1.4pp) |
| Biomass | 8.1% | 7.2% | 8.3% (+0.2pp) | 7.4% (+0.2pp) |
| Hydro | 1.5% | 5.6% | 1.4% (-0.1pp) | 4.9% (-0.7pp) |
| Hydro Storage | 0.0% | 0.2% | 0.1% (+0.1pp) | 0.3% (+0.1pp) |
| Coal | 0.7% | 0.8% | 0.0% (-0.7pp) | 0.2% (-0.6pp) |
3.6 Key Trend
Great Britain's electricity consumption is led by ~32.6% wind. Solar saw the biggest growth from 6.8% to 8.2%.
4. Cross-Border Electricity Flows
Great Britain imported a net 28.43 TWh in 2025.
4.1 2025 Gross Exports (Great Britain → Neighbor)
Total electricity exported to each country — with average carbon intensity
4.2 2025 Gross Imports (Neighbor → Great Britain)
Total electricity imported from each country — with average carbon intensity
4.3 Net Position by Neighbor (2025)
| Neighbor | Net (TWh) | Direction |
|---|---|---|
| IE | +9.02 | Net Exporter |
| IM | +0.20 | Net Exporter |
| NL | -0.38 | Net Importer |
| BE | -2.14 | Net Importer |
| DK | -5.16 | Net Importer |
| NO | -16.37 | Net Importer |
| FR | -21.01 | Net Importer |
Positive = Great Britain is net exporter to that neighbor. Negative = Great Britain is net importer from that neighbor.
4.4 Flow Pattern by Hour of Day
Peak imports at 11:00 (4.6 GW avg).
4.5 Internal Flows Between Bidding Zones
Great Britain consists of multiple bidding zones with internal transmission links. These flows represent electricity transfers between zones within the country.
| Link | Net Flow (TWh) | Avg CI (g/kWh) |
|---|---|---|
| GB → GB-NIR | +2.17 | 189 |
| GB → GB-ORK | -0.02 | 99 |
Positive = net flow in the direction indicated. These are internal transfers and do not count as imports/exports.
5. Carbon Intensity (gCO₂eq/kWh)
5.1 Daily Records
| Metric | 2024 | 2025 |
|---|---|---|
| Lowest Carbon Intensity | 65.6 g (Apr 05, 2024) | 70.2 g (Oct 26, 2025) |
| Lowest Fossil % | 8.2% (Apr 05, 2024) | 7.9% (May 29, 2025) |
| Highest Carbon Intensity | 360.2 g (Dec 12, 2024) | 348.0 g (Jan 20, 2025) |
| Highest Fossil % | 68.7% (Dec 12, 2024) | 65.1% (Jan 20, 2025) |
5.2 Hourly Records
| Metric | 2024 | 2025 |
|---|---|---|
| Lowest Carbon Intensity | 44.1 g (Aug 29, 2024 10:00) | 50.7 g (May 29, 2025 09:00) |
| Highest Carbon Intensity | 384.4 g (Dec 12, 2024 06:00) | 379.2 g (Jan 22, 2025 07:00) |
5.3 Days Below Thresholds
| Threshold | 2024 | 2025 | Δ |
|---|---|---|---|
| < 100 gCO₂eq/kWh | 40 | 38 | -2 |
| < 200 gCO₂eq/kWh | 250 | 243 | -7 |
| < 300 gCO₂eq/kWh | 354 | 356 | +2 |
5.4 Hours Below Thresholds
| Threshold | 2024 | 2025 | Δ |
|---|---|---|---|
| < 100 gCO₂eq/kWh | 1,727 | 1,780 | +53 |
| < 200 gCO₂eq/kWh | 5,879 | 5,683 | -196 |
| < 300 gCO₂eq/kWh | 8,298 | 8,328 | +30 |
5.5 Average Carbon Intensity by Hour of Day
5.6 Seasonal Carbon Intensity Patterns
Carbon intensity daily patterns shift with seasonal changes in renewable generation and electricity demand.
Winter (Dec-Feb)
Peak: 234 g @ 17:00 | Trough: 149 g @ 03:00 | Spread: 85 g
Spring (Mar-May)
Peak: 223 g @ 19:00 | Trough: 124 g @ 13:00 | Spread: 99 g
Summer (Jun-Aug)
Peak: 210 g @ 20:00 | Trough: 113 g @ 13:00 | Spread: 97 g
Fall (Sep-Nov)
Peak: 215 g @ 18:00 | Trough: 142 g @ 02:00 | Spread: 73 g
Summer offers the lowest carbon intensity, with midday troughs reaching 113 gCO₂/kWh—24% lower than winter. Scheduling flexible loads during seasonal low-carbon windows maximizes emission reductions.
5.7 Carbon Intensity Distribution (Hourly)
Notable monthly evolutions
Change: +29% vs Apr 2024
Change: +34% vs Aug 2024
Change: -22% vs Nov 2024
1,621 hours with both low price (<£70/MWh) and low carbon intensity (<108 gCO₂eq/kWh).
5.8 Multi-Level Carbon Intensity Heatmap
Carbon Intensity Heatmap
gCO₂eq/kWh
hourly range: 51-379
Yearly
Monthly
Daily
Hourly
6. Renewable & Carbon-Free Energy (Flow-Traced)
Includes electricity exchanged with neighboring grids
6.1 Days Above Thresholds
Days with carbon-free share above threshold
| Threshold | 2024 | 2025 | Δ |
|---|---|---|---|
| ≥50% carbon-free | 205 | 212 | +7 |
| ≥60% carbon-free | 98 | 115 | +17 |
| ≥70% carbon-free | 14 | 21 | +7 |
6.2 Hours Above Thresholds
Hours with carbon-free share above threshold
| Threshold | 2024 | 2025 | Δ |
|---|---|---|---|
| ≥50% carbon-free | 4,816 | 5,019 | +203 |
| ≥60% carbon-free | 2,795 | 3,139 | +344 |
| ≥70% carbon-free | 813 | 1,185 | +372 |
6.3 Multi-Level Carbon-Free % Heatmap
Carbon-Free % Heatmap
%
hourly range: 28-96
Yearly
Monthly
Daily
Hourly
