GB Grid Stability Digest

The week on the grid — 26 October – 1 November 2026

Issue 2026-w44

Frequency spent 4 minutes outside 50 ± 0.2 Hz across nine separate excursions, the longest 2 minutes, ranging 49.787 Hz–50.248 Hz.

The system imbalance price peaked at £350/MWh in settlement period 28 on 2026-11-01.

The system price went negative in 2 settlement periods, bottoming at −£16/MWh.

Vital signs

	This week	vs last week
Inertia min / avg / max	137.8 / 186.2 / 242.6 GVA·s	▲ +9.2 GVA·s (min)
Frequency range	49.787–50.248 Hz · 38.1 hours beyond ±0.1 Hz	▲ +0.030 Hz (min)
Peak wind + solar share	63.4% (Tue 12:31)	▲ +4.9 pp
Peak demand	23.0 GW (Thu 00:00)	▲ +0.1 GW
System price max / min	£350/MWh / −£16/MWh	▲ +£75/MWh (max)

Event of the week

IFA, the 2000 MW interconnector to France, lost 1500 MW of capacity at Mon 09:04 — back after 445.9 hours. REMIT gives the cause as "Under Investigation"; 4 other unplanned losses over 300 MW were reported in the week.

Balancing auctions

NESO's day-ahead auction bought £4.56m of frequency response and reserve across 7 delivery days this week.

	Avg price	vs last week
Dynamic Containment Low	£4.34/MW/h	▲ £0.26
Dynamic Containment High	£2.70/MW/h	▲ £0.33
Dynamic Moderation Low	£10.33/MW/h	▲ £1.13
Dynamic Moderation High	£0.01/MW/h	▼ £0.46
Dynamic Regulation Low	£23.11/MW/h	▲ £7.08
Dynamic Regulation High	−£14.05/MW/h	▼ £3.04
Positive Quick Reserve	£4.17/MW/h	▼ £0.44
Negative Quick Reserve	£3.04/MW/h	▼ £0.53
Positive Balancing Reserve	£2.89/MW/h	▲ £1.06
Positive Slow Reserve	£1.89/MW/h	▲ £0.35