The Battle for Energy-Efficient Buildings

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© N. Tiget/CNRS Photothèque

Jean-Bernard Saulnier
Deputy Scientific Director of the CNRS Information and Engineering Sciences department.

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The Energy Research Program launched by CNRS in 2001 and currently headed by Monique Lallemand,¹ places special emphasis on research aimed at reducing energy consumption. One of the program's goals, which is also shared by other bodies, is to use the resources of its research teams to find ways of eventually moving away from today's energy-consuming buildings to more environmentally-friendly buildings that are net producers of energy.

CNRS' contribution is in line with France's commitments under the Kyoto Protocol, namely to diversify its sources of energy, increase its energy self-sufficiency, and reduce greenhouse gas emissions, thus paving the way for genuine sustainable development. Optimizing energy production and management is of course essential if we are to achieve this, but we also need to improve our knowledge in the fields of materials science and civil engineering, and even welcome potential integrations of new communication technologies, which are already being used in the aviation and automobile industries, and are now starting to be applied to buildings.

With regard to energy, two key areas have been identified: Firstly, it is necessary to reduce the quantity of energy used for heating, for instance by using novel superinsulating materials and “active” windows which adapt with sufficient accuracy to energy demand (heating or cooling); and secondly, we need to make use of renewable energies while at the same time developing an energy management strategy specifically adapted to their often intermittent nature. For instance, in order to make use of solar energy, buildings need to incorporate photovoltaic electricity generation systems which are as efficient and cost-effective as possible. The booming global market in silicon cells already raises the issue of availability of this material for use in solar energy applications. CNRS is working on innovative projects in this field, in collaboration with national French electricity provider EDF, and has set up a network of around thirty laboratories carrying out research into photovoltaic polymers. And one should also consider thermal solar energy, where a novel approach to refrigeration and cooling systems is under way.

The need to ensure sustainable power supplies means developing efficient processes not only for electricity generation but also for storage (both electrical and thermal), as well as combining irregular sources of energy with continuous ones such as near-surface geothermal energy. It also means managing energy carriers (heat, cold, electricity, etc.) by designing distribution networks with a view to optimal efficiency: This work is being carried out by ten laboratories working in the field of thermal sciences, as well as another ten involved in electrical engineering.

Finally, we shouldn't forget to mention the essential role played by socioeconomic research, which, for instance, analyzes what drives energy demand and consumer behavior and studies the optimization of energy supply chains (buy-back price per kWh of photovoltaic electricity) and incentive schemes.

The Energy Research Program has without doubt enabled CNRS to organize its resources in order to attempt to meet this key national goal. However, besides these first encouraging results in research structuration, CNRS, together with the French Atomic Energy Agency (CEA) and the University of Savoie, is committing itself further by setting up the National Solar Energy Institute² in Chambéry, which will help to strengthen France's position in this crucially important field.