Energy savings

A greener heating network

Agropellets (c) Generia

For more than ten years, Paris La Défense has been supporting the greening of the district heating network. After the initiatives taken in the Hoche eco-district and more recently in the ZAC des Groues, the area is preparing to enter a new energy era. When heat production is part of a circular and virtuous economy, we all win!

Environmental issues and the reduction of CO2 emissions do not stop with the construction of buildings. The production of hot water and heating and the operation of cooling systems also require energy. It is therefore necessary to reduce and green these consumptions!

Who is in charge of this?

Generia, the union in charge of organizing and operating the public heating and cooling service in La Défense, Seine-Arche in Nanterre and La Garenne-Colombes.

Generia therefore ensures the smooth operation of four separate networks, including the one operated by Idex La Défense, which supplies 3 million square meters, i.e. 120 office buildings and 20,000 inhabitants! Today, this network uses 36% renewable energy and operates with a heat pump (TPP). Doesn't that tell you something? It is in fact a heat pump that simultaneously produces heating and cooling! And thanks to these installations, CO2 emissions have been divided by 2 since 2014.

Idex La Défense, 2016 (c) 11h45

The energy of plants

Paris La Défense is not stopping there! With the connection of the entire Les Groues operation, a major energy evolution is underway. At the end of the first quarter of 2023, part of the district heating installations will be adapted to run not on fuel oil but on agropellets, plant pellets produced from agricultural residues. The territory has therefore decided to take up the challenge and use this new energy resource to supply the heating network.

Agropellets have many advantages in terms of environmental and societal impacts:

  • Valorization of agricultural residues;
  • Sustainable and renewable resource;
  • Reduction of CO2 production;
  • Recycling of the ash generated by combustion into non-polluting fertilizer.

And to further limit the carbon impact, the short circuit is also favored since most of the wheat pellets are produced near the Paris region and transported by rail. Nothing is lost, everything is transformed. That's what a virtuous cycle is all about!

Neighborhoods focused on sustainable development

When the ZAC des Groues was created in 2016, the public institution's ambition was clear for this future district: to place sustainable development at the heart of the real estate programs and reduce carbon emissions per user by a factor of four. These objectives gave the developers a framework for the design of the housing units and the choice of materials.

Heating plant of the Hoche Nanterre eco-neighborhood, 2016 (c) Carlos Ayesta

In the early 2010s, the public institution signed a concession contract with the company Enerbiosa for the operation of a biomass-fueled heating plant. Its purpose is to cover the heating and hot water needs of the new Hoche eco-neighborhood in Nanterre.

The four-hectare eco-neighborhood is now home to low-energy housing, public facilities and shops. In order to reduce the environmental impact of thermal energy production and to improve the economic and social balance of the heating network, Paris La Défense and Enerbosia opted for wood as the source of energy to supply the boiler! This mixture of crushed raw wood and forestry chips will cover 80% of the heat needed to produce heating and hot water.

Did you know that?

  • The length of the Paris La Défense heating network? 26 kilometers!
  • The quantity of wheat pellets delivered each week? 24,000 tons.
  • The number of CO2 emissions avoided each year? 54,000 tons.

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