Recycled aluminum in RTE's high voltage lines

As France prepares its energy transition, "we are going to have very, very strong decarbonization, both in the area of ​​electricity production and electricity consumption", recalled Delphine Porfirio, director of the consultation department. and environment at RTE.

Wind turbines at sea, on land, photovoltaic fields and, in the more distant future, nuclear power plants, "all these new forms of production, we are going to have to connect them to the electricity transmission network", she underlined.

This new situation, combined with an aging network and therefore in need of renewal, leads RTE to invest from 2024 "of the order of 2 billion euros, and this will continue to increase in future years".

If aluminum, unlike many metals in the energy transition, does not pose a resource problem, its production from bauxite results in an often complex supply chain and its production is very energy intensive and emits carbon, not to mention the release of red mud into the environment.

Hence the idea of ​​“recovering” the aluminum from old electrical cables “to then be able to reinject it into the manufacturing process of new cables,” explains Ms. Porfirio. It is also a way of strengthening France's industrial sovereignty in critical metals, a concern at the heart of a summit organized this week in Paris by the International Energy Agency (IEA).

RTE thus took cable removed from electrical lines in the Savoyard Maurienne valley. This cable was cut, before being entrusted to the MTB company which separated the aluminum from the rest of the materials.

This second-hand aluminum was then melted with high-purity primary aluminum by the German group Trimet, in its furnaces in Saint-Jean-de-Maurienne.

These recycled aluminum wires will be used by cable manufacturers, “who will therefore manufacture electrical cable used on our lines,” said Ms. Porfirio.

“What we recovered in Maurienne allowed us to manufacture 40 kilometers of electrical circuit, which partly equipped the lines that we renewed on French territory” in the summer of 2023, in Corrèze and Maine- et-Loire, she said.

RTE, which will have, in 2024 alone, some 600 kilometers of lines to replace on the French network, now hopes to "transform the test and turn this experiment into a real industrial sector".

Trimet France did not wish to give the proportion of second-hand aluminum incorporated, but "it is in two figures, it is not homeopathic", indicated Loïc Maenner, general director of Trimet France.

He specifies that “remelting recycled aluminum consumes 5% of the energy needed to produce primary aluminum”. However, despite these energy savings, the more complex operation entails additional costs, which could be reduced in the event of a sharp increase in the volumes processed.