Major Outage

North Sea Link tripped on 13 June 2025, reducing UK power imports from Norway by approximately 1.4 GW. The loss of in-feed caused GB grid frequency to fall as low as 49.66 Hz, below NESO's operational limits of 49.8–50.2 Hz. NESO's contracted low-frequency response (roughly 2 GW procured at an average price of £4.80/MW/hr) plus a 500 MW Quick Reserve allocation activated, and Static Firm Frequency Response (SFFR) contributed about 240 MW — a rarely-used service typically reserved for interconnector loss-of-infeed events. Over 60 grid-scale BESS assets managed via Kraken delivered roughly 40% of the lost volume, supplementing combined-cycle gas turbine balancing required to stabilise the system. The event was the second major NSL trip in nine months, following the 8 October 2024 trip that produced a similar 1.4 GW loss-of-infeed.