July 5, 2024
Construction Site in Saint-Julien-des-Landes: Birdsong Louder Than the Noise of Machinery
In Saint-Julien-des-Landes (85), the Vendée Departmental Energy and Infrastructure Authority is testing new equipment on an electrical connection project on behalf of the municipality, in partnership with Bouygues Energie & Services, a subsidiary of Equans France. Using electric and BioNGV-powered machinery on this project has optimized carbon and noise footprints compared to a conventional project. The electric excavator emits four times less CO₂ on site than a diesel excavator.
Electric Vehicles and Bio-NGV: The Keys to a Less Polluting Construction Site
At the construction site in Saint-Julien-des-Landes (85), even as excavators and trucks go about their work, the sound of birdsong persists and dominates. This is the surprise of this pilot project, which is equipped with low-emission machinery as requested by SYDEV, the Vendée Departmental Energy and Infrastructure Authority, a major player in the energy transition across the Vendée region. The site features an electrical connection via a 250-meter trench. It’s an ideal test case: one week of construction, with an electric charging station 2 km away. All service vehicles have been replaced with electric models instead of diesel ones; trucks, cranes, and vans now run on BioNGV (Natural Gas for Vehicles derived from anaerobic digestion). The following equipment was used on the job site: a Mecalac 12 MTX electric excavator, a 6x2 CNG dual-dump truck, a CNG construction van, an electric pile driver, and a DN350 electric cutter.
SYDEV and Bouygues Energies & Services were able to assess the construction site’s carbon footprint using Nooco software, which enables companies to measure and optimize the environmental impact of their construction projects. The calculations produced by this software tool are recognized by the industry and RE2020-certified; however, the carbon footprint calculated in this way remains an estimate, limited by the available information about the construction site and the calculation method. The comparison between this “green” construction site and a conventional one is clear: in Saint-Julien-des-Landes, CO2 emissions are reduced by approximately 22.5%. In fact, the carbon footprint of this construction site in the Vendée region amounts to 11,653.83 kg CO2 eq. CO₂ equivalent, whereas the simulation for a construction site using conventional vehicles and machinery running on GNR (Natural Gas for Road Transport) amounts to 14,276.68 kg CO₂ equivalent. For this analysis, the quality teams at Bouygues Energies & Services assumed that BioNGV emitted 80% less CO2 than diesel (source: ADEME).
The electric excavator is four times less polluting than a conventional excavator
In terms of the project’s environmental impact, transport vehicles and the electric excavator rank only fifth and sixth, behind aggregates, site facilities, and inert waste treatment. The equipment accounts for 3.25% of carbon emissions, compared to 14.7% for a conventional construction site. The difference is significant.
According to these same calculations, the e-MTX electric excavator emits four times less CO₂ than a diesel excavator (typically used on construction sites): 319 kg CO₂ eq. versus 1,263 kg CO₂ eq. CO2. It proved to be an indispensable part of this test site due to its power, range, and good stability on the ground while carrying a load.
The noise assessment is also positive. Typically, crews wear helmets equipped with walkie-talkies to communicate while the machines are operating. On this job site in Saint-Julien-des-Landes, the workers did not need to use this communication equipment.
When the electric excavator is digging the trench, the measured noise level is 56 decibels... A low level of noise that allows for better communication between the excavator operator and the utility line installers. It is important to note that wearing ear protection is mandatory on job sites where noise levels exceed 85 decibels. The use of electric equipment and BioNGV thus makes it possible to operate virtually silent construction sites, improving working conditions for the employees involved and respecting the daily lives of nearby residents.
This successful initial test has provided valuable insights for further reducing the environmental impact of electrical work, particularly by increasing the use of machinery and vehicles powered by electricity and renewable energy, but also by broadening the scope of investigation to include other sources of CO2 emissions.
