ElecLink

A 51-metre battery-powered work train, built by Clayton Equipment, laid the ElecLink cable along the Channel Tunnel between February and summer 2021. No ship was involved, and no cable touches the seabed: the whole 51 km route runs inside the tunnel, from a converter station at Folkestone to one at Peuplingues on the French side.

The idea was to use a structure that already crossed the strait. That made the engineering simpler and the approvals harder. The Channel Tunnel Intergovernmental Commission, which oversees safety in the tunnel for both governments, suspended its consent in 2019 over concerns about an HVDC cable sharing space with passenger and freight trains. An approval expected in April 2020 slipped because of further safety questions and the pandemic. The commission gave its approval in December 2020, and final clearance followed in February 2022. ElecLink began commercial operation on 25 May 2022, according to the ElecLink article.

Work on the project had started in 2017 and it cost £490 million. Prysmian made the cable, Siemens built the converter stations and Balfour Beatty installed it; Siemens’ order announcement describes a 1,000 MW voltage-source scheme at ±320 kV. ElecLink is owned by Getlink, the tunnel’s operator, and it was the first UK interconnector funded entirely by private finance with no underwriting from electricity consumers.

The converter stations are only half the route. Underground AC cables run a further 14.5 km on the English side to Sellindge and 3.5 km on the French side to Les Mandarins, the same two substations that anchor the 1986 IFA link. So three cross-Channel links now meet at two points, a concentration worth keeping in mind when you read about the fire at Sellindge in 2021.

Getlink’s choice has a quiet advantage for a power cable: inside a tunnel, no anchor can drag across it. For comparison with seabed routes, see the guide to subsea power cables.