The last trenchless structure for the Celtic Interconnector project has just been completed: a 126-meter-long HDD river crossing that marks the end of 15 months of intense trenchless work in Brittany.
This last crossing, drilled by Gendry and monitored by OPTIMUM, passed 10 meters under a coastal river through sands and granite rock. Despite being in a wetland area with limited access, no breakouts occurred, thanks notably to careful monitoring of the drilling and mud parameters. This was particularly important given the protected woodland areas and houses nearby. Inspections have now confirmed the HDD’s structural integrity, ready for installation of the high-voltage cables: 2 HDPE ducts of DN 225 and 5 HDPE ducts of DN 63.
Another step in Europe’s energy transition ! The Celtic Interconnector project will be the very first HVDC interconnection between Ireland and mainland Europe, increasing the safety, stability and quality of the electricity supply between the two countries.
OPTIMUM has supported RTE from the outset, from the choice of landfall site, through preparatory engineering and overseeing the construction of all the trenchless works:
- 3 x HDD landfalls, totalling 1320 meters, drilling through hard granite.
- 1 x 84 metre long AVN 1200 microtunnel under railway tracks, tunnelling through slate schist.
- 1 x 126-metre-long HDD river crossing, drilling through sand and granite.
A big thank you to RTE for this unique opportunity, and congratulations to our dedicated team.
The Celtic Interconnector project is supported by the Connecting Europe Facility (CEF) funding program.
