This project in photos
Massive Urban Works
Bouygues Construction took the helm of an immense project: Marseille’s L2 bypass— the A507 urban motorway several kilometres long. Signed on 7 October 2013 by Transport Minister Frédéric Cuvillier and Bouygues Construction Deputy CEO Philippe Bonnave, this public‑private partnership was France’s largest infrastructure contract of 2013, totalling €620 million. Once completed, the free, fully grade‑separated ring road will relieve Marseille’s main arteries of heavy traffic.
Beyond installing Dualsun solar panels, several systems were selected to curb energy use on the site:
•Solar water‑heating
•Double‑flow heat‑recovery ventilation
•Reversible heat pumps
•Rain‑water recovery tanks feeding the vehicle‑wash stations
More broadly, the Société de la Rocade L2 (SRL2) has implemented extensive measures to mitigate the bypass’s environmental footprint: Mediterranean‑adapted landscaping, optimised materials management, reuse of excavated spoil, storm‑water control, and LED lighting.
An HQE building equipped with Dualsun panels
SRL2—a consortium that includes Bouygues Construction—holds the 30‑year design‑build‑finance‑maintain contract for the L2. Its operations centre (CEI) houses SRL2 staff, Provence motorway police (CRS), and DIR Mediterranée road‑operation teams.
The CEI office block was built to France’s RT 2012 energy code and HQE (High Environmental Quality) standards. Eight Dualsun hybrid panels were installed on its roof: the PV output supplies the building’s own electricity, while the thermal loop provides hot water for the intervention teams’ showers.
Bouygues Construction thus renews its confidence in Dualsun—after fitting 180 Dualsun hybrid panels on its positive‑energy headquarters “Challenger” back in 2014.
Interview – Cyril Gonzalez‑Attias
Project manager, Bouygues Bâtiment Centre‑Sud‑Est (CEI construction)
Why did you choose Dualsun for this project?
The CEI in Clérissy resembled a programme we delivered five years earlier—63 CEIs nationwide for the DIR. Those projects used PV to meet HQE, BBC and RT 2005 targets.
Here, roof area was tiny—around 3 m². The HQE consultant proposed hybrid panels to produce both electricity and hot water. Dualsun’s solution met all requirements.
How did the installation go?
Smoothly. Dualsun supplied our subcontractor; I liaised with Dualsun on the design, while the installer handled technical details.
Do you often specify renewables?
Solar is still uncommon on our standard builds; it appears mainly on RT 2012 or HQE sites. In residential it’s far more widespread. Ultimately, uptake depends on client specifications.
Interview – Pascal Béria
Deputy Managing Director, Société de la Rocade L2 (SRL2)
What is SRL2’s stance on renewables?
The L2 itself runs on conventional power contracts, but the Clérissy CEI pushes further: RT 2012 and HQE were required from day one.
Feedback on the Dualsun panels?
The contract was signed in October 2013; the CEI has only just been delivered, so operational data aren’t yet available. The panels are clearly visible from the road, and we’ll track their performance in the coming months. Electricity will serve the building; thermal output will supply staff showers. We’re optimistic—time will tell.
