GB Grid Stability Digest
The week on the grid — 31 August – 6 September 2026
Issue 2026-w36
Frequency spent 15.8 minutes outside 50 ± 0.2 Hz across 17 separate excursions, the longest 2.8 minutes, ranging 49.745 Hz–50.240 Hz.
The system price went negative in 43 settlement periods, bottoming at −£85/MWh.
The system imbalance price peaked at £240/MWh in settlement period 35 on 2026-09-02.
Vital signs
| This week | vs last week | |
|---|---|---|
| Inertia min / avg / max | 124.0 / 150.9 / 195.3 GVA·s | ▼ −5.1 GVA·s (min) |
| Frequency range | 49.745–50.240 Hz · 43.6 hours beyond ±0.1 Hz | ▼ −0.058 Hz (min) |
| Peak wind + solar share | 69.5% (Sun 13:45) | ▲ +8.9 pp |
| Peak demand | 22.6 GW (Tue 01:00) | ▼ −1.2 GW |
| System price max / min | £240/MWh / −£85/MWh | ▼ −£24/MWh (max) |
Event of the week
RYHPS-1, a VPI Power Limited fossil gas unit, went out unexpectedly at Fri 20:00, taking 715 MW off the system — back after 50 hours. REMIT gives the cause as "Commercial"; 4 other unplanned losses over 300 MW were reported in the week.
Learn: Interconnectors and stability
GB trades power with its neighbours over HVDC links. Imports displace domestic generation — which changes how much inertia is on the system.
Read the explainer →Get this in your inbox
One email every Monday morning: the week on the GB grid, in numbers. No spam, unsubscribe any time.
Data: Elexon BMRS · NESO · Carbon Intensity API · Sheffield Solar · All issues
Free to reuse with attribution (CC BY 4.0).