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District heating and cooling networks at Paris Saclay Campus

Deep geothermal energy to power the entire Paris-Saclay

The Paris Saclay Urban Campus is a major project in Greater Paris. With the planned 1.74 million sqm construction, it combines scientific ambition, economic development and sustainable management to strengthen the city’s position among the global centres of innovation. This is a unique opportunity to develop a new energy model and make Paris Saclay an Eco-Area. Establishing a smart grid for low temperature cooling and heating using deep geothermal energy will help make Paris Saclay a positive energy area.

What our stakeolders tink

“This new network plays a key role in the strategy to make Paris Saclay a green area. The deployment of this solution on such a scale will be a world first”

 Pierre Veltz, Chairman and CEO of EPAPS (Etablissement Public d’Aménagement de Saclay)

An Energy Transition plan

A solution in line with the energy transition law and COP21 to move from a society with high fossil fuel consumption to a society that is more energy and carbon efficient.image-saclay

  • A solution that has a carbon footprint three times lower than conventional gas heating
  • Savings close to 20% for the subscribers

The project led by EPAPS is one of 11 winning projects in the “Industrial demonstrators for the sustainable city” call for projects, launched in October 2015 in preparation for COP21. The aim of this call for projects was to select operations intended to become a showcase for French excellence in sustainable development.

The Egis/IDEX[1] consortium won the seven-year contract awarded by EPAPS with a transfer of skills to Design-Production-Operations & Maintenance (CREM) for the provision of heating and cooling in both joint development zones[2]. Egis is involved in the design, project management and turnkey implementation of the network within the scope of its association with IDEX.

The Egis/IDEX group proposed a temperate network via a geothermal doublet[3] in Albian[4] powering the blocks’ substations (distributed generation). This provides heating and cooling to the blocks, thus avoiding the need for extra/emergency gas resources in the buildings of the lessees. This system is also able to adapt to changes in the programme at block level.

In the block sub-station, the thermo-refrigerating pumps are designed to cover at the very least the entire chilled water needs for their block. To evacuate their surplus cooling or heating power to the temperate network, the block substations are equipped with heat exchangers. One exchange unit will evacuate the excess cooling power and another the excess heating power. This latter unit will have a dual function because if the requirement for heat is greater than the block’s production capacity, it will also provide extra heat. In these circumstances, the delivery temperature of the temperate network is raised in order to supplement the heat production from the thermo-refrigerating pumps. This temperature increase, which may reach 105°C, will be controlled via the smart grid. It will be activated by the operating team, during the installation process, with regard to projected demand curves.

[1] IDEX: to find out more (french website)

[2] Corresponding to two strategic districts on the urban campus: that of Vauve (Polytechnic college) in the towns of Palaiseau and Saclay, and that of Moulon in the towns of Gif-sur-Yvette, Orsay and Saint-Aubin.

[3] The doublet technology helps protect the environment and ensure the sustainability of water resources. It consists of two boreholes, one for production and one for the re-injection of thermal water into its original water table.

[4] The Albian aquifer measures over 100,000 km², with an average depth of 600 m, protecting it from surface pollution. Its estimated temperature of between 25°C and 28°C makes it a vital source of geothermal energy. The Albian water table extends beneath the entire Paris Basin.

Deep geothermal energy to meet demand for heating, hot water, air conditioning and cooling


Users by 2021
  • 2100 Student homes
  • 2400 Family homes
  • 520,000 sqm Higher education, research, economic development and public facilities
Production and consumption
  • 37 MW Maximum heating power output
  • 10 MW Maximum cooling capacity
  • 40 GWh Annual  heating energy supplied by the network
  • 10 GWh Annual cooling energy supplied by the network
Environmental performance
  • 37 MW Maximum heating power output
  • 10 MW Maximum cooling capacity
  • 40 GWh Annual  heating energy supplied by the network
  • 10 GWh Annual cooling energy supplied by the network

Significant benefits

Added value for the environment Added value for the economy Added value for society
  • Re-using the geothermal resource (geothermal water at 31°C)
  • Renewable energy coverage rate (62%)
  • Scalable networks for medium-term re-use of waste heat[1]
  •  Operation of thermal Smart Grid-type networks (optimised management of production tools in accordance with demand)[1] Waste heat: heat generation derived from a production site, but where this is not the primary purpose, and which, as a result, is not necessarily re-used (for example, services buildings that house data-centres whose waste heat is not re-used).
  • Cold production at block level is more efficient than standalone systems for each building
  • Reduction of consumption (very low-temperature heat distribution network, over-insulation of underground pipes, etc.)
  • Consideration of equipment maintenance during the design phase
  •  Longer lifespan of equipment
  • Lower energy bills for tenants and landlords
  • Deploying a solution on this scale will be a world first, making Paris-Saclay a showcase for formidable technological endeavour.

Eventually, the network will supply all the campus buildings built between 2016 and 2022

District heating and cooling in Asnières sur Seine - french town
The Z.A.C. Business Park in Asnières is being made into an eco-district. Egis is in charge of designing a heat network based on geothermal energy, alongside Eiffage Energie, which will operate it. It is a turnkey Egis project (design, construction, financing, operation and maintenance) for a developer consortium. In 2022, the network will supply 1,730 homes, a retirement home for the elderly, 4,900 sqm of shops, 30,000 sqm of offices, a school and a nursery.

  • Over 60% of distributed energy will be from geothermal power
  • A network that can adapt economically to the business park’s development over 48 months
  • A scalable project that can extend beyond the needs of the area.