Fire at an HVDC converter station leads to site evacuation and loss of interconnector capacity
Sept 2021Published 1 May 2026Responsible editor: Chief Editor
- Where
- HVDC converter station serving subsea interconnector, United Kingdom
- What
- Fire broke out, site evacuated, interconnector capacity lost
- Injuries
- None reported
- Cause
- Under investigation
- Outcome
- Flows fell to zero, day ahead prices rose over 2,500 pounds per MWh
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What happened
In September 2021, a fire broke out at a high voltage direct current converter station in the United Kingdom serving a subsea interconnector to continental Europe. The site was evacuated and emergency services attended. The link is arranged as two poles of equal rating, and one pole was already out of service on a planned maintenance outage before the fire, so available capacity had already been reduced by half. Following the fire, the status of the affected pole was changed on a European transparency platform from a planned outage to an unplanned outage, and reported flows on the link fell to zero.
The event coincided with tight system conditions, and day ahead prices for the immediate evening peak period rose to over 2,500 pounds per MWh. The national system operator stated that sufficient operating margin was forecast for that evening's peak demand period. No injuries to personnel were reported and the site evacuation was completed without incident.
Contributing factors
Public statements at the time emphasised the safety of staff, emergency responders and local residents as the priority. The cause was the subject of a formal investigation and was not disclosed in the public reporting available at the time of writing, so no causal factors are recorded here. Reporting noted only that one pole of the link was already out of service for planned maintenance when the fire occurred.
Lessons learned
- One pole of a bipole HVDC link already on planned outage means any fire on the remaining pole removes all capacity, so operators must plan operational response for that state.
- HVDC converter station evacuation must include a defined high voltage de-energisation and earthing sequence shared with emergency services in advance.
- Any change in interconnector availability appears quickly on public platforms, so operators must prepare holding statements and notification routes.
More lessons on outages, backup supply and restoration, electrical protection and isolation, emergency response and public communication, from every incident on the register.
Not yet known
- Cause of the fire
- Converter station equipment model and age
- Duration of the outage and cost of damage
This entry is updated when these are reported. Get an alert for the next one like it.
Source
Published 2026-05-01. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
