On a small road, about ten kilometers from Auray (Morbihan), Enedis agents, aided by employees of service companies, carefully dismantled almost a kilometer of electrical cables, using pulleys, to replace them with a single cable, longer larger and more resistant.
It is one of approximately 3,500 projects planned by the distribution network operator in Brittany over the next five years. “We want to make the region the laboratory of the grid’s resilience to climate change»assures Hervé Champenois, technical director of Enedis. Brittany has 109,000 kilometers of electricity lines.
A network “chopped” by storm Ciaran
A real challenge, since storms, increasingly frequent and violent due to global warming, each time cause extensive damage to the plants, many of which were built more than half a century ago. This is the case of storm Ciaran, which just one year ago, on the night between 1 and 2 November 2023, crossed Brittany with wind gusts of up to 207 km/h at the tip of the Raz.
The damage to the network was extensive, with trees falling on the lines, poles broken, distribution stations and transformers torn. “An unprecedented event in Brittany, the impact of which was two to three times more significant than the storms of 1999”underlines Hervé Champenois, speaking of“a dismembered electricity grid”. In total, 1.2 million homes remained without electricity in France, including 780,000 in Brittany.
Although in the end more than 90% of the houses were renovated in four days, the EDF subsidiary now says it wants “learning lessons” expanding its work program in Brittany. The investment plan adopted in the summer of 2023 envisaged strengthening the reliability of 3,500 km of lines between 2025 and 2029, with a budget of 390 million euros. Enedis announced on Monday 28 October its intention to make another 2,000 km more reliable, for a cost currently being defined.
Drones to check the status of the lines
The “Reconstruction of Brittany” plan therefore envisages the burial of 1,100 km of lines, i.e. 700 km more than expected before storm Ciaran. This will happen especially in the areas most prone to accidents, where for example there are trees. It is also planned to renew 800 km of air network, in addition to the 2,200 km already budgeted. Drones, combined with an artificial intelligence program, are already carrying out inspection flights along the cables to check which ones need to be renewed first.
a specific section concerns the progressive abandonment of wires “us”these uninsulated copper lines, much more numerous in Brittany than elsewhere. In all, 1,400 km (out of 7,500 km) will be replaced by twisted cables, which is 500 km more.
“The goal is for future storms to cause less damage and fewer outages, so that electricity can be restored to 90 percent of homes within forty-eight hours, twice as fast as currently.”»assures Pascal Pouzac, regional director of Enedis. The switch from bare wire to braided wire reduces the risk of accidents by seven to eight times and the planned renewal of the lines reduces the failure rate by 30%.
Burying the lines allows us to increase the number of interruptions tenfold in the event of a climatic event, but the price remains high: between 100 and 150 euros per meter versus 20-25 euros per meter above ground. “For each project it will be necessary to define a technical-economic optimum », underlines Pierre-Olivier Courtois, head of the Reconstruction Bretagne project, who also hopes to have enough subcontracting companies.
25 billion euros to adapt the network
There will be no shortage of work to develop and modernize electricity grids at a time of energy transition. Enedis speaks of 96 billion euros in the period, of which 25 billion euros linked to the adaptation of lines to climate change.
You have to know how to deal with storms, like in Brittany, but also floods. “We have never experienced so many in one year»underlines Hervé Champenois. After last autumn’s floods in the Hauts-de-France, Enedis decided to raise its source stations, the systems the size of half a football field that connect the high voltage and medium voltage RTE network.
There is also an increase in heat waves in urban areas, which can damage power lines. However, they are buried but starting to show their age. In many large cities, cables are still wrapped in impregnated paper (CPI) normally intended to be insulating, but which appears to have poor heat resistance, with the appearance of condensation in particular. A large program to replace 700 km of cables per year has been launched and needs to be accelerated.
Interview Between Time.news Editor and Hervé Champenois, Technical Director of Enedis
Time.news Editor: Thank you for joining us today, Hervé. Your work is crucial for the resilience of electricity in Brittany, especially after recent events. Can you start by telling us a bit about the ongoing projects that Enedis is undertaking in the region?
Hervé Champenois: Thank you for having me. We currently have around 3,500 projects planned over the next five years in Brittany. A significant aspect of these initiatives is to make the region a laboratory for the electricity grid’s resilience to climate change. We’re undertaking projects like replacing nearly a kilometer of electrical cables with longer, larger, and more resistant alternatives, which is essential in our aim to improve overall reliability.
Editor: That’s impressive, especially considering the increasing frequency of severe weather events. The recent storm Ciaran had a devastating impact. Can you elaborate on the challenges faced during that event and how it catalyzed these new projects?
Hervé: Storm Ciaran was unprecedented, with wind gusts reaching up to 207 km/h. It caused extensive damage, and around 1.2 million homes lost electricity across France, including 780,000 in Brittany alone. The storm highlighted the fragility of our infrastructure, much of which is over 50 years old. This led us to not only repair but to learn and enhance our infrastructure, expanding our work to strengthen 3,500 kilometers of lines with a 390 million euro investment plan.
Editor: It sounds like the storm was a wake-up call. In response, you’ve increased the scope of your projects, including burying more power lines. Why is this important for the future?
Hervé: Burying lines significantly reduces the risk of damage from storms and falling trees. After Ciaran, we’ve decided to increase the amount of buried lines from the initial 400 km to 1,100 km. This proactive measure will minimize outages and enhance reliability, particularly in areas prone to storm damage.
Editor: Utilizing technology seems to play a big role in your strategy. Can you explain how drones and AI are being incorporated into your inspections?
Hervé: Absolutely. We are using drones equipped with AI programs to inspect our lines. They can identify which cables need renewal more efficiently than traditional methods. This tech-driven approach allows us to prioritize maintenance and upgrades based on real-time conditions, ultimately enhancing the system’s resilience.
Editor: That forward-thinking approach is commendable. You’ve mentioned the move away from uninsulated copper lines to braided wires. How does this change contribute to increasing safety and reliability?
Hervé: Transitioning from bare wires to braided wires drastically reduces the risk of accidents—by up to eight times. Alongside this, planned line renewals can decrease failure rates by about 30%. Our ultimate goal is to ensure that in the event of future storms, we can restore electricity to 90% of homes within 48 hours, effectively halving the current times.
Editor: It sounds like a comprehensive effort to bolster the electricity grid in Brittany. What do you envision for the future, not just for Brittany, but potentially as a model for other regions?
Hervé: Our vision is for Brittany to become a benchmark for grid resilience against climate change. By demonstrating the effectiveness of these innovations and upgrades here, we hope to inspire similar initiatives in other regions facing the same challenges. It is vital that we adapt to these changing climate dynamics not just for today but for the future.
Editor: Thank you, Hervé, for your insights and for the important work Enedis is doing to ensure a more resilient electricity network. It’s encouraging to hear about proactive measures being taken to adapt to climate challenges.
Hervé: Thank you for the opportunity to discuss our projects. It’s an important conversation, and we’re committed to leading the way in making our infrastructure more resilient.