IFA1 published a General Information update (May 2025) on its official website that made Regional Nomination Platform (RNP v2) resources and Open API documentation available to market participants. The update provided RNP2 OpenAPI specifications and multiple PDF guidance documents (business model kit and nomination APIs) to support participant registration, nomination and interface with TSOs and market platforms (NESO, Elexon, JAO). The release was intended to facilitate operational interactions between market participants and the IFA interconnector's nomination/registration systems.
On 22 December 2023 a fault occurred on the IFA1 HVDC interconnector between France and the UK that caused a full outage of the link. IFA1 comprises two independent bipole cables (each ~1 GW); the link was already operating at half outage when a fault on the second cable tripped the remaining circuit. The fault produced a rapid system frequency disturbance in Great Britain (frequency dropped quickly towards ~49.5 Hz) and led to the loss of around 2 GW of import capacity, contributing to generator trips and system balancing actions. National Grid ESO deployed frequency response and generation resources to restore stability. This event was reported in industry coverage and technical commentary.
National Grid restored IFA1 to full commercial service (the full 2 GW capacity) on 27 January 2023 following the rebuild and commissioning work to recover equipment damaged by the 2021 converter‑hall fire. The return to full service reinstated the interconnector’s full transmission capability between Sellindge (GB) and Les Mandarins (FR), increasing overall GB interconnector capacity.
As part of the Sellindge converter station rebuild, installation, commissioning and integrated system testing of HVDC equipment and supporting systems — including control, protection and ancillary systems — were completed to validate safe operation and enable full return to service. The testing programme concluded when site systems passed commissioning checks and operational acceptance tests prior to the link operating at full capacity.
In 2021 a fire occurred at the IFA1 terminal which materially reduced the interconnector’s availability. Government and market reviews later cited the terminal fire as an example of a high-impact, low-probability event that affected interconnector performance and capacity-market availability assessments.
Following a major fire at the Sellindge converter station in September 2021, National Grid restored the link to limited service at approximately half capacity (circa 1 GW) as an intermediate energisation and trial operation while repair and rebuild works continued. This partial return to service provided constrained interconnector capability ahead of full repair and allowed limited cross‑Channel flows during the restoration programme.
RTE and National Grid submitted and published the IFA Border-Specific Annex to the Harmonised Allocation Rules (the TSOs' proposal) on 13 April 2017. The document defined allocation and nomination arrangements for the France–England IFA border (including Long Term Transmission Rights), set rules for curtailment, invoicing and collateral, and amended aspects of the IFA Access Rules to reflect IFA-specific operational and market procedures. The publication constituted a formal TSOs' filing/proposal to apply harmonised allocation rules to the IFA interconnector and provided the regulatory and operational framework for capacity allocation and related TSO processes at the IFA border.
The subsea and onshore cable installation campaign was completed in 1986 and the IFA1 interconnector was commissioned that year. The completed system comprised the subsea section and the landside cable runs connecting the UK landing near Folkestone to Sellindge converter station and the French landing near Calais to Les Mandarins converter station, enabling bi-directional HVDC operation at 2,000 MW.
Landfall operations for IFA1 — the shore pull-ins and connections at the UK landing near Folkestone and the French landing near Calais — were completed as part of the overall installation and commissioning programme in 1986. The landside cable sections (the English and French onshore runs) were installed and tied into the respective converter station infrastructure prior to the interconnector entering service.
IFA1 (Interconnexion France-Angleterre), the original 2,000 MW HVDC cross-Channel interconnector between Sellindge (UK) and Les Mandarins (France), was fully commissioned in March 1986. Cable installation had been completed in 1985, with commissioning and testing following through early 1986. The link was jointly developed by CEGB (now National Grid) and EdF (now RTE) as the first major electricity interconnector between Great Britain and continental Europe.
| United Kingdom | France | |
|---|---|---|
| Landfall | Monks Hill Beach (southern end of Solent Airfield / Daedalus), near Portsmouth, Hampshire, UK | Landfall east of Merville‑Franceville‑Plage (near Caen), Normandy, France |
| Grid Connection | Sellindge converter station (Sellindge, GB) | Les Mandarins converter station (Les Mandarins, FR) |
United Kingdom
France