In response to the severe storm Ciaran, Enedis is enhancing Brittany’s power grid by burying 1,100 kilometers of overhead lines underground to withstand extreme weather. This initiative, part of a broader 2,000-kilometer reinforcement plan, aims to protect the infrastructure against increasing climatic risks. The project involves complex cable installation and is backed by significant funding as part of a national climate adaptation strategy. Enedis emphasizes the urgency of these upgrades to ensure reliable electricity supply during future storms.
In a quaint corner of Brittany, workers equipped with hard hats diligently install the last sections of underground electric cables, committed to reinforcing the region’s power infrastructure. This project signals a robust response to extreme weather challenges, one year after the impactful storm Ciaran.
“We excavate the area, set the cable into the ground, layer it with sand for protection, and finally seal it up,” details Frédéric Bobier, the project manager at Allez et Cie. This company is a partner of Enedis, the primary entity overseeing France’s electricity distribution network, and is actively engaged in this project located in Ergué-Gabéric, northeast of Quimper (Finistère).
In this initiative, Enedis is replacing approximately 5 kilometers of overhead lines—those conspicuous wires strung high above the ground on wooden or concrete poles—with more resilient underground cables.
Overall, there are plans to bury around 1,100 kilometers of power lines in Brittany, a small segment of the extensive 108,000-kilometer electricity network serving the region.
The goal is clear: “To enhance the resilience of Brittany’s power grid in light of storm Ciaran,” notes Pierre-Olivier Courtois, head of the ‘Reconstruction Bretagne’ initiative at Enedis. He recalls the devastation caused by exceptional winds a year earlier, which resulted in trees collapsing onto the grid and causing significant disruptions.
This reconstruction effort is set to fortify an additional 2,000 kilometers of power lines over the next five years, with a budget currently under review (potentially exceeding 200 million euros, as estimated by AFP). This initiative is in addition to Enedis’s ongoing plans to refurbish 3,500 kilometers of Breton lines scheduled for 2025-2029, at an estimated cost of 390 million euros.
As the autumn sun casts its light, an excavator on-site diligently fills an 80-centimeter trench where workers have secured a medium-voltage line, expected to supply electricity to local industries and businesses by the end of December.
– Time is of the Essence –
“We must act swiftly” to ensure the power grid can withstand “increasingly severe and localized climatic events,” emphasizes Hervé Champenois, Enedis’s technical director, during a site visit to the Breton teams.
Burying power lines is highlighted as a key recommendation in the latest National Climate Change Adaptation Plan (PNACC-3), introduced recently to equip national infrastructures for a potential 4°C increase in global temperatures by 2100, relative to pre-industrial levels.
Will overhead power lines vanish from the landscape?
“That’s not the objective,” reassures Pierre-Olivier Courtois, as he navigates towards a project site in Brech, north of Auray (Morbihan). Burying cables comes with a high price tag—costing five times more than upgrading above-ground lines—making it a priority mainly in areas with dense tree cover.
A sharp noise interrupts the discussion as a worker below unwinds a large, twisted black cable, which is then elevated by another worker in a gondola to be secured atop a concrete pole.
During the storm Ciaran, power was out in this hamlet for “ten to fifteen days,” while 90% of the 1.2 million homes affected had their power restored within four days, aerates the head of the rebuilding plan.
The existing low-voltage network in Brittany, particularly susceptible to downed trees or coastal salt deposits, relies heavily on bare copper wires. Transitioning to more resilient twisted aluminum cables encased in plastic is a key strategy to weatherproof the grid.
The ‘twisted’ wiring that Enedis plans to implement across 1,400 kilometers of existing lines ensures that “customers will remain powered even if the line fails,” facilitating quick repairs, as he explains.
However, “during a storm like this, it becomes a race against time.”
Frequent storms in Brittany, flooding in various regions, and urban heatwaves are prompting Enedis to allocate roughly 1.3 billion euros annually towards upgrading and reinforcing the power grid in response to climate change. This investment represents a significant portion of the company’s €96 billion development strategy through 2040.