GB Grid Stability Digest
The week on the grid — 13–19 July 2026
Issue 2026-w29
The system imbalance price peaked at £220/MWh in settlement period 17 on 2026-07-13.
Wind and solar peaked at 56.5% of GB generation at Sun 14:30.
System inertia ranged from 67.8 GVA·s to 113.5 GVA·s (average 82.0 GVA·s).
Vital signs
| This week | vs last week | |
|---|---|---|
| Inertia min / avg / max | 67.8 / 82.0 / 113.5 GVA·s | ▲ +3.8 GVA·s (min) |
| Frequency range (sampled) | 50.010–50.010 Hz · none beyond ±0.1 Hz | ▼ −0.060 Hz (min) |
| Peak wind + solar share | 56.5% (Sun 14:30) | ▼ −8.5 pp |
| Peak demand | 22.1 GW (Sun 07:45) | ▲ +0.5 GW |
| System price max / min | £220/MWh / −£12/MWh | ▲ +£10/MWh (max) |
Event of the week
The system price went negative in 13 settlement periods, bottoming at −£12/MWh.
Partial data coverage this week (17 of 168 hours) — coverage grows as snapshot history accumulates.
Learn: Battery storage and grid balancing
Grid-scale batteries respond to frequency deviations in under a second — far faster than thermal plant. They’re now a core part of GB’s stability toolkit.
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Data: Elexon BMRS · NESO · Carbon Intensity API · Sheffield Solar · All issues