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sustainable constructionThe first autonomous building concept in France

Insights
5 min
25/06/2020

Sustainability

At Grenoble, Bouygues Construction is just finishing up its ABC demonstrator, a residential complex designed to be water and energy autonomous as well as more comfortable for the people who live in it. An in depth look at this project that brings green buildings to life.
By Grâce Noyal
solar panels with mountains in background
construction worker

In the new Presqu’île eco-neighborhood at Grenoble, they are hard to miss. Topped with arrays of 688 solar panels, the two apartment buildings based on the ABC (Autonomous Building for Citizens) concept rise imposingly at the foot of the Chartreuse mountains. The concept is extremely ambitious, and this 62-apartment residence, which is designed to be energy autonomous, to consume 70% less water from the public water system, and to optimize waste management, is its first concrete application in France.

solar panel

Origins in R&D

The project was conceived by research and development teams at Bouygues Construction, under the encouragement of Gaëtan Desruelles, then executive vice president, R&D, Innovation and Sustainable Construction. “We were already experimenting with buildings that would produce energy or that would manage water more sensibly,” recalls Thierry Juif, environment and eco-design director at Bouygues Construction. “Gaëtan Desruelles asked us to imagine a building that would push these concepts to the extreme.” So, the team began to think about how to design a building that would meet a list of environmental challenges, as Juif explains: “It would produce energy autonomously. It would use rainwater and recycle wastewater. It would reduce the quantities of waste produced. It would be built with materials having a low environmental impact. It would also have to be as comfortable for its inhabitants as a traditional building so that they didn't have the feeling of going backwards”

tracks

A project for the planet

After several years of research, Bouygues Construction signed an agreement in 2014 with the city of Grenoble to build France's first ABC demonstrator in the Presqu’île neighborhood, a government-certified eco-housing development. “We needed a lot of partners to carry out such an ambitious project,” notes Roseline Legrand, director for the Auvergne-Rhône-Alpes region of Linkcity Sud-Est, the property development subsidiary of Bouygues Construction. “Grenoble and its metropolitan area were eager to get on board.” Managing resources and lowering carbon emissions are major issues here in the Alps, where the effects of global warming are being felt twice as fast as elsewhere and in very concrete ways such as shrinking glaciers and more days of high temperatures. The project is also receiving support from the state through its Investment Program for the Future and from the Auvergne-Rhône-Alpes regional authority.

people riding bikes
Éric Bard
CEO, Grenoble Habitat
“With the ABC apartments, we have two aims: to reduce the environmental footprint of the apartments and to reintroduce in a major city the collective living spaces and mutual support found in small communities. Thanks to the vision of the R&D teams at Bouygues Construction, the people of Grenoble will be part of this new step toward the home of the future that is adapted to its environment.”
tracks

A series of innovations:
electricity

“In the ABC project, we went looking for the best solutions on the market,” says Vincent Joly, the project's manager at Bouygues Bâtiment Sud-Est. “I've never seen so many innovations used in a single project! And for a housing project, it was technically very complex.” The electricity will be produced by the 1,130 sq. m of photovoltaic panels in the solar farm installed on the roofs of the two apartment buildings. Grenoble's gas and electric utility GEG ENeR will operate the installation. Electricity will be stored in lithiumion batteries and redistributed in the mornings and evenings, during peak consumption. The residents of the ABC buildings will have the option of buying the electricity produced by this farm in the first collective auto-consumption system in France. The buildings are designed to consume little energy. Each apartment will have double exposure and tight seals around doors and windows. Theoretically, it will not be necessary to use the battery-powered electric radiators for heating. All the apartments will be delivered with a kitchen outfitted with lowconsumption electrical appliances, and lighting will be provided with energy-saving LED lamps.

...to water management

Water management is the project's other big plus. The goal is to decrease consumption from the public water system by three, reducing it to less than 50 liters per person a day. Rainwater running off the solar panels will be recovered, potabilized in an on-site, short-circuit treatment system, and mixed with city water to re-mineralize it. Wastewater containing organic matter will be treated in a miniature plant installed by Suez on the ground floor and then used for the toilets and watering plants. Even the heat from greywater (i.e., household water containing little pollution) will be recovered with a heat pump and used to warm the sanitary water. The bathrooms will be equipped with recycling showers and shower heads that beam colored light to indicate in real time how much water has been consumed.

Renters play a role

Another objective of the project is social diversity. A social landlord, Grenoble Habitat, has bought the 62 apartments and will rent them as low- or medium-range housing so that these innovations are available not just to better-off individuals. The well-being of future tenants is also a prime concern. For example, each apartment will have its own individual and customizable dual-flow air handling units to which special filters like those for pollen can be added. “Another aim is to involve the renters, get them to change their behavior, and create a community where people interact with each other,” says Emilie Tourenne, operations manager at Linkcity Sud-Est. “We're seeing a lot of enthusiasm for the project. One hundred or so potential renters have already visited the model apartments and the information showroom connected to it. Candidates must submit an application, including a questionnaire designed to find out why they are interested. For the project to work, the renters have to buy into it! That's why they will be given support by the Atelier Pop-Corn, a startup that will act as a community leader and help everyone learn how his or her new home works.”

table
buildings blue sky
Tenants will be asked to do their part and encouraged to sort their refuse using the bins already provided in the kitchens and a compost pile, which is intended for the shared kitchen gardens. Also, an app developed in-house by Bouygues Construction will give tenants information in real time about the building's behavior and their apartment's consumption. Hundreds of sensors have been installed to supply data for all these indicators and to measure all the benefits. Bouygues Construction has agreed to monitor the project for five years and precisely assess its environmental impact as well as the residents' behavior. At Grenoble, the energy transition is already underway.

Key figures

÷3
Consumption from the public water system
-40%
household waste
70%
autonomy for electricity daily
107%
of annual electricity needs satisfied by the solar farm
Photo credit Nedim Imre