Support for energy optimisation of the future EOLE station at Porte Maillot (extension of RER line E)

What innovative solutions for optimising the energy efficiency of a station?


SNCF Réseau, owner of the EOLE project to extend RER line E, called on Efficacity to implement an eco-design approach to the future Porte Maillot station.


The principal mission of the annual R&D partnership between SNCF EOLE and Efficacity consisted of optimising the energy performance of the future RER line E station at Porte Maillot thanks to:

  • Studies of possible optimisations of station power balances;
  • Analysis of potential means of recovering shallow geothermal energy (specific drilling, thermoactive diaphragm walls) ;
  • Study of potential means of recovering waste energy (technical service areas, the Canadian well principle, geo-cooling, free cooling);
  • Study of possible means of recovering RER train braking energy;
  • Presentation of the principles of electrical plant (microgrid) management.


This method provided SNCF with a second opinion on the proposals put forwards by prime contractors, and an initial series of analyses identified several avenues for energy optimisation.

For each of these avenues, a state of the art review was drawn up, comprising a description of the challenges and the associated commercial solutions, plus feedback from around the world.

A comparative analysis was carried out of the relative merits of geothermal technology using diaphragm walls as against geothermal energy from groundwater.

Efficacity provided a second opinion on the Porte Maillot station power balance, identifying redundancies, power levels under normal operations as compared to maximum power, and power levels in degraded mode and simultaneous use.

On the basis of this analysis, a real balance situation was proposed and presented in the station power balance file. Efficacity was able to propose a significant gain of around 20% compared to the heat inputs estimated by the prime contractor and integrator, by revising the various input data provided by the prime contractors (setpoint temperature, safety rules, limit coefficient, etc.).


Dates 2016 – 2017

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Cette méthode a permis d’offrir à la SNCF un second regard sur les propositions des maîtres d’œuvre et une série d’analyses permettant d’identifier plusieurs pistes d’optimisation énergétique