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Published on September 16, 2021

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How we reduced carbon footprint and respected biodiversity on an high-speed rail project ?

SEA (Sud Europe Atlantique) consists of 302km of high-speed rail (HSR) between Tours and Bordeaux (France). Egis was a partner in the winning PPP JV led by Vinci to design & construct, then operate and maintain the 300km HSR line for 30 years. As part of its activities, Egis also performed the environmental studies including obtaining the associated consents.


- Crédits : © Gérard Meilley

We delivered the project based on 3 main environmental principles:

  • reduce the carbon footprint
  • respect for biodiversity
  • include the local communities as part of the solution

Reducing carbon footprint

By undertaking a carbon assessment exercise, we identified the major contributors to carbon emission at various stages of the project. Looking at infrastructure, we projected that approximately 90% of carbon would be emitted during the construction phase and the three major contributors would be railway structures (44%), earth structures (24%) and railway superstructures (18%).

With this insight, we set the following objectives:

-reduction in the volume of materials and therefore the volume transported

-reduction of energy consumption linked to transportation of people and maintenance of plant and equipment

-reduction of energy consumption during construction and operation

We reduced by 500,000 tonnes the greenhouse gas (GHG) emissions compared to the baseline from the preliminary design phase, i.e. a GHG reduction of 20% overall (25% for the construction phase).

We achieved this by:

1) Optimisation of the railway structures using low carbon materials and promoting the standardisation of structures to achieve a 49% reduction in GHG emissions on standard structures.

2) Optimisation of earthwork in order to reduce borrow pits to achieve more than 25% reduction in GHG emissions.

3) Optimisation of concrete transportation logistics by locating batching plants strategically to reduce the average travel distance from 30km to 20km.

4) Optimisation of maintenance equipment by promoting the use of modular structures for easy installation and longer term maintenance to achieve a 14% reduction in GHG emissions.

5) Implementation of eco-driving for the transport of people and materials by road to achieve a reduction in energy consumption for construction equipment and 8% for light vehicles.

6) Improving the environmental performance of the site and operating premises as part of a High Environmental Quality (HEQ) approach with permanent positive energy buildings and a 50% reduction in the consumption at temporary premises.

The creation of a carbon foundation

To further improve the project’s environmental credentials, we created the SEA carbon foundation. The foundation proactively involved the local communities to help them adopt a carbon neutral mindset. We supported 89 local communities projects to reduce their emissions by 10,800 tons of CO2 equivalent each year, representing the lighting needs a city of 250 000 inhabitants. One of these projects included the replacement of fuel oil by wood pellets as the central heating fuel source in people’s houses.

 Respecting Biodiversity

  • 223 protected species

Over 200 protected animal species that required protective measures were identified. We reached out to nine main NGO environmental associations, France Nature Environment being the largest, and integrated them within the project team to correctly identify the protected species. This way we devised and implemented accurate mitigation measures to comply with the legislations whilst respecting the balance of biodiversity. We not only confirmed the above list of protected animals, but also found additional wild animals that were thought to be extinct in France. 

The “avoid, reduce, offset” approach, notably by creating 840 ecological transparency works

Where the project crossed environmentally sensitive areas, we adopted a three level action plan. The first level was to avoid impact, the second level was to reduce the impacts and finally if these two were not possible, we applied mitigation measures. For example, vegetation within the alignment was removed and replanted elsewhere. This measure was implemented at a ratio of three-four to one, usually by using falllow agricultural land so that the resulting forested area increased.

We assessed the carbon emission of three railheads used during the construction stage. We reviewed our logistics planning to ensure that measures were implemented to mitigate potential impacts associated with the use of diesel locomotives and fuel storage.

The results were:

  • 3,800 ha of environmental mitigate measures, including:
  • 70% of sites managed by agreements with farmers and owners
  • 30% by the acquisition of plots of land, representing over 1,000 ha and 82 sites

An environmental permitting process with the participation of more than 100 homeowner associations

We managed the environmental regulation procedures to obtain the required permits and approvals in a progressive and timely manner. We established effective communications with national government authority, regional and local authorities and the general public. In terms of general public outreach, we consulted with over 100 adjacent homeowner associations to get their inputs to the environmental regulatory process. The environmental permits and approvals were obtained according to schedule, thereby assuring that the construction started as planned. In addition to obtaining these regulatory authorisations and approvals, we consulted with and kept informed the contractor consortium’s insurance companies who closely followed the project to make sure that the regulatory process did not negatively impact the project. 

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