Flexibility, key to the Paris-Saclay heating and cooling grid!

Flexibility, key to the Paris-Saclay heating and cooling grid!

As one of the five pilot sites of the D2Grids project, Paris Saclay aims to enhance its energy efficiency and reduce greenhouse gas emissions. For that purpose, the 5GDHC Paris-Saclay grid is one of the keys.

Nicolas Eyraud, project director of Paris-Saclay 5GDHC grid, presented during D2Grids closing conference a video providing insights into the grid’s operation within the Centrale-Supélec campus, in particular the innovative demonstrator. Lucas Lazzarini, energy engineer at Seqens, provided insights highlighting the operation of incorporating solar electricity into the grid thanks to pv panels on the roofs of their buildings while consuming the heat from it, as a “prosumer”.

As Lucas Lazzarini mentions, Seqens has been trusted by Paris Saclay 5GDHC grid with the development of three units within the ZAC du Moulon district. Recognizing the district's ambitions, Seqens conducted studies on the implementation of solar panels to optimize roof surfaces. The primary objective was to achieve self-consumption of the energy produced. However, it was found that the production fell short of meeting the demand, with less than 50% of the energy being self-consumed.

In response to this challenge, Seqens identified the heating and cooling grid as a significant local consumer that could use the excess renewable energy. Extensive studies were conducted to install hybrid thermal and photovoltaic (PV) panels, thereby enhancing the flexibility of the grid. However, the studies revealed certain obstacles. Retrofitting hybrid panels on pre-designed buildings posed difficulties, as the existing wood structures required modifications to support the heavier panels. Additionally, scatter panels were found to be inconvenient for central hot water production, and the existing substations were not large enough to accommodate storage tanks. These factors would have adversely affected the efficiency of both systems.

On the other hand, the installation of PV panels and the establishment of collective self-consumption with the grid offered technical, financial, and administrative simplicities. This approach allowed Seqens to generate 59 kWp and 64 MWh/year. The proximity between the production and consumption points, within less than 2 km, facilitated the sale of excess electricity. This local electricity sale arrangement eliminated the need to pay the grid use component, proving financially advantageous for both the seller and the buyer.

Furthermore, the studies emphasized the high replicability of the project for both new and existing buildings. Seqens identified an opportunity to enhance the roof of a nearby building during a rehabilitation project, thereby replicating the collective self-consumption scheme. This initiative resulted in the installation of 44 kWp and the generation of 49 MWh/year.


The video presented by Nicolas Eyraud highlighted that the DHC grid in Paris-Saclay supplies energy to most buildings on the urban campus. As part of the D2Grids project, the grid has implemented an advanced thermal demand management demonstrator. The primary goal of this demonstrator is to enhance thermal flexibility, reduce energy consumption, and decrease greenhouse gas emissions. Detailed information on the demonstrator can be found in this article.

The project partners, including various associations and student organizations such as Césal (the manager of student residences), Technologis, and Aretic, were also presented during the video. Their contributions play a crucial role in ensuring the successful operation of the grid.

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D2Grids Project