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SESAC Site Grenoble


Project status



The main metropolis of the French Alps with 530,000 inhabitants, at the junction of three Alpine valleys, is a city in a dense populated area surrounded by nature. Grenoble suffers from being a sink for pollution.  The short term target is to reduce CO2 emissions by 14% until 2014 (compared to 2005), to reduce energy consumption per inhabitant by 2014 and to increase the share of renewable energy to attain a level of 14% of all energy consumed. Between 2004 and 2007, the emissions were reduced by 7%.


Site facts and figures

  • Estimated population involved:  approx. 35,000
  • Geographical area coverage: 2.133 km²
  • Approx. energy saving: 41%
  • Approx. energy from RES:  21%



12 new eco-buildings (equal to 850 dwellings) are built in the De Bonne area. Nine of these multi-storey buildings (435 dwellings) are part of the CONCERTO demonstration project. The design of the buildings includes compact dimensions, specific insulation values, double-flow ventilation, water and light efficient equipment. They will be supplied by natural gas mini cogeneration units (CHP) for heat and electricity and by solar thermal panels for 40% of Domestic Hot Water needs. The CHP units will cover half of the heating needs as well as 100% of the electricity needs.

Among the new tertiary buildings are an energy-efficient elementary school (Picture 1) and a positive energy office building (Picture 2). The school is a two-level building with 2973 m² of gross area, mixed concrete and a timber structure with external insulation, low-emission glazes, with a special focus on thermal bridges, a simple flow ventilation with pre-heated air, low consumption computers and a green roof. The office building is heated and cooled by groundwater and has a large photovoltaic installation.

Photovoltaic plant are installed at three other buildings (another office building, a shopping centre and a stadium) and will in total reach a peak power of 315 kW.

Beside De Bonne the other demonstration area is “La Viscose” (Picture 3). The district-heating network will be expanded to this area and supply by biomass and solar energy is added, substituting a coal heating plant (62 MW). The grid will supply 280 existing dwellings and the 59 new apartments to be built within CONCERTO.


District heating at „La Viscose“

This demonstration activity is situated in a social housing area, called “La Viscose”. The 277 dwellings (in total 20 000 m²) for industry workmen were built around 1930 and are distributed in 57 minor buildings with 2 to 4 dwellings each. The very expensive individual electric heating systems are changed to biomass district heating with a short and local energy-chain, provided by pieced-wood from forests around Grenoble (Picture 4). The number of dwellings was reduced to increase their size and install a bathroom in every flat. The roofs were refurbished and double-glazing and new doors were installed. The insulation consists of an external 10 cm layer of glass wool or polystyrene, which was installed on all but two of the old buildings.

By these measures 5,000 KWh of energy could be saved per year and the annual CO2 emissions could be reduced by 264 tons. The project also aims to develop cost cutting approaches and standardised technical and contractual solutions for similar RES conversions in other social housing areas.


Mini CHPs in De Bonne

A large number of new buildings has been constructed at the “De Bonne” district. At nine of the eco-buildings mini cogeneration plants (CHP) were installed. They provide heating, domestic Hot Water (DHW) and electricity for the new dwellings through feed-in tariff contracts. The total capacity installed amounts to 290 kWel and 590 kWth. Each mini CHP capacity has been adapted to cover 50% of the heating and DHW needs of the buildings. The estimated efficiency is around 85% (35% of electricity and 50% of heat).

Due to financial and technical reasons, the plants are not running during the “summer” period from April to October. Gas boilers and solar panels cover the rest of the needs (extra needs during winter time and all needs during summer time); these solar panels cover about 40% of the total DHW consumption.

The choice of mini co-generation was also driven by the aim of testing the right size and settlement standards for small co-generation plants and to motivate and support the import/distribution market chain for mini-cogeneration. Such a market does not yet exist in France. This also allows to put the market for distributed co-generation implementation in progress much faster and more significantly than with big plants.


Positive Energy Office Building

At „De Bonne“ area an energy-efficient office building shows the good results of an integrated panning process.

The aim was to build a new innovative, positive-energy office building with a consumption of energy 70% below applicable building standards in France and producing 16,000 kWh of extra primary energy each year.

The building has four floors and a size of 1,784 m² (gross area), it is a concrete structure and has external insulation (special regard to thermal bridges). The heating and cooling is provided by a heat pump, using the groundwater as source of energy (Figure 1). A focus was put on light control, favouring natural light. Innovative windows are installed as well as double flow ventilation for the whole building and a simple flow for each room. The building uses a 425 m² photovoltaic power plant to produce more energy than required, taking into account all energy efficiency efforts.

The expected consumption of electricity is 41,300 kWh per year (less than 27 kWh/m²), which represents 6 times less than the consumption of a building complying with the current French regulations. The expected electricity production from the PV plant is 47,500 kWh per year.


Figure 1 – Sketch of the building concept © CR&ON
Figure 1 – Sketch of the building concept © CR&ON

Lessons learnt

The following information has been gathered as part of the CONCERTO Premium policy research.

Benefits of CONCERTO:

Key benefits:

The CONCERTO project enabled Grenoble’s De Bonne neighborhood to be selected from amongst 160 others cities as the winner of the first National “Eco-district” Prize in 2009 SESAC was very important for Grenoble and very successful. The regeneration of the “Bonne” area was strategically important, as it is a 10ha site in the center of Grenoble, near the historic center. Military barracks were partly refurbished partly demolished, making way for new buildings. The project had the aim to bring young families into the town center, rather than only students and older people.

CONCERTO helped to define and fix ambitious energy targets and to ensure to adhere to them. In Grenoble, the large number of SESAC buildings and energy projects paved the way for new procurement and contracting procedure towards Private Developers. Previous praxis of having Private Developers develop “in line with standard”, had been replaced with an innovative combination of contractually agreed energy performance requirements, targeting training and a new third party verification scheme. Another innovative cooperation was the cross-incentive based project development between the Social Housing Company OPAC 38 and the Heating Company, Compagnie de Chauffage. They jointly financed a conversion from expensive electrical heating to cheaper and more environmentally friendly bio fuel district heating for the tenants.

Skill development:

Initially in Grenoble and then in the other French CONCERTO Communities, participants developed new skills. These newly-found skills not only ensured that installations were correctly implemented, but also gave construction workers a chance to raise their employment possibilities in the future.

Regarding training activities, Grenoble launched a vast training operations aimed at architects, engineers and individual building workers. In this way the importance of the correct use of RES and eco-friendly materials and techniques has been brought to the pillars of the construction sector. In France, a training model developed within the SESAC project in Grenoble for on-site workers has been kept by to the national level of construction association. They also contribute to stimulating interdisciplinary awareness on construction sites, as specialized workers need knowledge about the work done by their colleagues from other technical fields in order better to coordinate their activities, thus improving the overall construction quality. Within SESAC training modules had to be developed and trainers had to be found- some from abroad (e.g. from Austria), some from construction product suppliers. Approximately 70 people attended the training events. There were also workshops for landlords/ clients. Since then and due to the involvement of ADEME such training courses became available. In the SESAC communites Grenoble, Delft and Växjö trainings on the environmental management system ecoBUDGET were organized.


Barriers encountered:

Legal barriers:

PV in De Bonne: Uncertain legislation regarding building integrated PV and speculations about future changes in the politically driven feed-in-tariffs prevent more private investments sometimes hindering or delay projects more than necessary.

Administrative barriers:

In France, there was still a lack of skills concerning planners, craftsmen, regulators and investors in particular concerning Energy efficiency refurbishment in all the chain from the preliminary to the monitoring and evaluation phase of a project development. Therefore, the Sesac project in Grenoble focused a part of their activity on developing new interactive training methods, introducing environmental awareness and environmentally conscious behavior, addressed to the whole chain of actors involved on the process. These experiences have been shared with the other French CONCERTO Communities and adapted to the project needs.

Another problem widespread in France was the inadequate regulation and rules for PV systems implementation and the grid connection. Grid connection application and approval procedure is still very complicated, with the main grid operator taking too long time for processing contracts.

Compared with Växjö and Delft, Grenoble had to deal with a much larger numbers of local partners (8-9).

  • The City as lead contractor,
  • the government of the metropolitan area
  • developers, a local ESCO, a social housing provider
  • a number of subcontractors and builders.

Technical barriers:

Building to new, higher standards required a complete and continuous chain of new documentation and routine There was a risk of going back to business as usual. As a solution, a step-by-step training base working model was implemented, handling day to day practices, and the initiative of having a third party consultant supporting the different stakeholders to uphold the SESAC objectives, was also deemed positive. The main lesson learnt was that this new type of cooperation take time, consume significant resources and need to be well anchored among the very top management of participating organizations and companies.

Economic barriers:

The French context is not favorable for CHP and particularly for mini and micro CHP, due mainly to the complexities of grid connection and the poor feed-in tariff for electricity. In CONCERTO-Generation one refurbishment projects were not recognized initially

Social barriers:

Not many financial resources and human means given by local authority for the LCP. In the voluntary process, there were no means to require the partners to do their actions and it’s difficult to manage a big number of partners with very various skills and missions (S.1, p.202). The biggest barrier was to convince builders of the need to build more energy efficiently. No appropriate training programmes for builders were available, nor trainers. As a solution, there was an intensive training campaign.


Success factors identified:

Technical Success Factors:

Training activities for builders. Most of the nine public and private developers are pretty satisfied with their involvement in Concert-Sesac project because they felt they raised their level to a better way of constructing  building.

Social Success factors:

Awareness campaigns for tenants, training models for each type of stakeholder involved in the planning and construction phase and on site workers, study tours for companies and municipalities to visit the SESAC cities. Some communities carried out also other activities to involve additional stakeholder groups, for example SMEs.

Institutional success factors:

In Grenoble, one of the main strengths of the CONCERTO project has been the City Council’s strong political commitment. “La Metro” agglomeration has been one of the first local authorities in France to set up a Local Climate Action Plan and a “Charter” signed in 2004. ZAC de Bonne and energy requirements imposed to real estate s stakeholders in sales contracts, specifically requesting to exceed RT2000 and RT 2005 requirements. Close contacts between all French CONCERTO-Projects.

To achieve the main goal, put into quantitative objectives, OPATB set several actions:

  • Accompanying program (toward housing, private and public tertiary sector, small trades)
  • energy audits
  • dissemination and training actions
  • financial system of grants and the combination of on-going assistancea strong financial incentive and the commitment of all the stakeholders involved has produced results that have exceeded the objectives.

Economic success factors:

In Grenoble, the large number of SESAC buildings and energy projects paved the way for new procurement and contracting procedure towards Private Developers. Previous praxis of having Private Developers develop “in line with standard”, has been replaced with an innovative combination of contractually agreed energy performance requirements, targeting training and a new third party verification scheme. Another innovative cooperation was the cross-incentive based project development between the Social Housing Company OPAC 38 and the Heating Company; Compagnie de Chauffage. They jointly financed a conversion from expensive electrical heating to cheaper and more environmentally friendly bio fuel district heating for the tenants. At the same time did the energy utility Compagnie de Chauffage reduce its VAT/Tax costs, since the substantial increase of bio fuels gave them a more “green” fuel-mix“.

Another new-thinking approach was the cross-financing used to decrease the tenant’s costs for converting away from expensive electrical heating to relatively cheaper and environmentally friendly wood chips district heating. Since the Energy Utility also could cut its VAT costs, due to the substantial increase of bio fuels in their fuel-mix, it received partially cost coverage this way also.


Grenoble was underpinning the Municipal decision to devote 20% of buildings to social housing 25 and up to 35% in some CONCERTO areas


Business models used:

  • Municipal utility company
  • local ESCO
  • The PV station on the football stadium - the electricity production and sale by a public structure to an energy supplier was quite new: specific contracts have been set up between la Métro and GEG.


Legacy – follow-on projects:

CONCERTO energy efficiency in buildings standards applied in De Bonne neighborhood have been replicated in other concerted planning areas “ZAC”. In the sesac communities (Växjö, Delft and Grenoble), stakeholder meetings were organized and involved actors of the local service sector (e.g. builders, architects, housing companies, etc.). During these meetings it was discussed how the results reached in the demonstration activities could be used in the day-to-day work of these stakeholders. In this way, it was tried to create a spill-over from the demonstration activities and to motivate companies to replicate construction techniques developed within the sesac project (e.g. wooden constructions, passive houses). The training modules for builders developed together with ADEME were made available to others. The energy requirements  developed for the “Cahier des charges” (part of Grenobles planning obligations) now apply for all new construction activities.

The scale of what have been achieved shows that an initiative targeted at all the Grenoble common hold properties is possible. Thus, the OPATB opened the way for a new collective initiative. It has been decided to broaden this scheme to the entire metropolitan area for common hold properties built between 1945 and 1975.

Most of the nine public and private developers now considered the energy objectives given for Concerto as the "natural" basis for their other buildings everywhere else. So did the SEM SAGES in each new procedure for selling site in Grenoble. All stakeholders were convinced that producing energy efficient envelope and systems should imperatively be taken into account as soon as possible, and that energy targets don't penalize architecture quality design of buildings. Nine small CHP had been installed in De Bonne eco-buildings with a different size.


Legacy - Policy Developments:

Contributions together with the Grand Lyon project, to the BBC (“Bâtiments Basse Consommation”) low energy standard were applied in Rhône Alpes Region. The so-called “cahier des charges de cession de terrain(CCCT)”  was one tool for stating energy requirements as part of the spatial planning system, which was used for stating CONCERTO energy requirements. This was applied to all following new projects in Grenoble.

The CONCERTO approach

The RE supply will be improved through building for photovoltaic (PV) plants for a total of ~315 kWp, using solar thermal energy for domestic hot water on all new buildings, covering around 45% of the domestic hot water requirements and to increase biomass sources for the district heating system. In addition to this, the installation of 9 natural gas mini-CHP units for new buildings in de Bonne will cover half of the heating needs as well as 100% of the electricity needs.

About 12 eco-buildings are built in de Bonne with a minimum of 50% lower energy consumption level than the national average. 59 new dwellings are being built in La Viscose area in Echirolles.

A new elementary school is built in Grenoble with a 50% lower energy consumption level than the national average.

A total of 305 kWp connected to the grid of the photovoltaic plant. Photovoltaic panels are installed on four new buildings (2 office buildings; one shopping area and a stadium).

In de Bonne a training programme raises awareness and trains construction companies in energy performance issues.


At the shopping centre in de Bonne generation of electricity from renewable energy sources is enhanced through different national measures and incentives, for example direct and indirect financial and fiscal measures.


Perrine Flouret
City of Grenoble

Building aspects

  • Installed Renewable Energy Sources
  • photovoltaic

Thematic Field

  • New Building(s)
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Project data