Towards a more “ecosystemic” energy performance of buildings
Controlling energy consumption has become an environmental, social and economic necessity, due to the numerous impacts on the biosphere and society as a whole: climate change, depletion of natural resources, deterioration of health, etc.
Scientists, through the IPCC in particular, warn us: humanity will not be able to adapt to global warming as it is being prepared, if we do not act.
“Optimizing the reduction of impacts implies starting by reducing needs, even before questions of efficiencý or substitution of energy vectors,” poses the High Council for the Climate. “The energy transition consists of moving from a model where the issue was mainly to adapt a production system to a consumption that we imagine to be constantly increasing, to a model where we must, on the contrary, adapt our consumption to the finite resources of the planet and to the urgency of slowing global warming,” summarizes Jean-Baptiste Lebrun, director of CLER – Network for Energy Transition . Given the urgent need to act, an integrated, holistic and co-constructed approach between all the players in the value chain seems necessary to meet the challenge of the energy transition in buildings.
Le bâtiment se positionne comme le secteur le plus consommateur d’énergie, avec 45 % de la consommation nationale et plus de 25 % des émissions de gaz effet de serre, soit 123 millions de tonnes par an. Cependant, les investissements dans l’efficacité énergétique des bâtiments ont augmenté de 40 % depuis la COP21. « Le fait que, pour la première fois depuis 2015, le taux de croissance annuel des investissements dans l’efficacité énergétique ait dépassé 3 % est un signal d’espoir », nous éclaire Inger Andersen, Directrice exécutive du PNUE. Le bâtiment représente assurément une partie des problèmes, mais aussi des solutions.
According to a recent report by the independent Building Performance Institute Europe (BPIE), in the European Union, new standards to reduce emissions in the new building sector will not be sufficient to meet the 2030 and 2050 climate targets, except in France and Flanders.
These territories have put in place measures that are considered sufficiently ambitious in at least one of the four priority areas: phasing out fossil fuels, limiting emissions, reserving a minimum share for renewables, and setting binding standards to limit energy consumption.
“For new buildings only, and on paper, yes. But some observers doubt that this is enough, especially since the strengthening of the Climate Package, entitled ‘Fit for 55’,” explains Thierry Rieser, manager of the engineering firm ENERTECH and member of the negaWatt association.
In France, the Pluriannual Energy Programs (PPE) and the National Low Carbon Strategy (SNBC) set out our hexagonal roadmaps for the energy transition and carbon neutrality in 2050. The SNBC “provides guidelines for implementing the transition to a low-carbon, circular and sustainable economy in all sectors of activity”.
The government says that the building industry is at the heart of this transition. This “leads to an in-depth transformation of all trades: from the manufacture of construction products to the design, construction, management and rehabilitation of structures,” explains the Energy Efficiency Center at Mines Paris Tech. The regulations governing new buildings are increasingly demanding in terms of energy performance (RE2020, Tertiary Decree, BACS Decree, Smart Readiness Indicator, etc.). The 2012 regulation, which had strengthened the thermal objectives, has just been replaced by the more comprehensive Environmental Regulation 2020 (RE2020). But despite the efforts of public policies, the quantified objectives are far from being achieved.
In terms of energy performance, the priority issue is not new construction. The aging of the population, the “Zero Net Artificialization” context, and the low turnover rate all play a role in the renewal of the housing stock. The housing of 2050 already exists in large part. The main challenge is renovation. “Of the 36 million homes in France today, the pool of renovable buildings could amount to between 20 and 30 million,” says Rémi Babut, Project Manager at the think tank The Shift Project. We need to reach a cruising speed of 700,000 to 800,000 “efficient renovation” operations per year.
Major organizations have reported on their research to achieve carbon neutrality by 2050:
ADEME has published numerous studies on these cross-cutting topics. It has proposed four “Transition(s) 2050” scenarios and a collaborative forward-looking approach with the Centre Scientifique et Technique du Bâtiment (CSTB): “Imagining tomorrow’s buildings together”, in which Bouygues Construction is one of the partners. The negaWatt association has published its fifth energy transition scenario for France. It examines each consumption sector, including buildings, and each energy production sector, based on the fundamentals: sobriety, efficiency and renewables. RTE (Réseau de transport d’électricité) has published the main findings of its prospective study “Futurs Énergétiques 2050”, based on six scenarios. The Shift Project think tank is working on its 15-part Plan for the Transformation of the French Economy (PTEF), including “Living in a low-carbon society” and “Employment, the driving force behind low-carbon transformation”. The purpose of these contributions is to provide analyses to feed public policies and to present the various sectors concerned with the likely or necessary structural transformations.
“The delay observed in France for the decarbonization of the building sector can be explained by the many blockages related to energy renovation: policies and measures unsuited to the needs of deep renovation, the long time needed for the renovation of buildings and the structuring of the sector, the low capacitý of households to finance, the lack of incentives and support in the residential but also the tertiary sector, the lack of mastery of technical solutions, or the lack of information,” considers the High Council for the Climate. Its report “Renovating better: lessons from Europe”, which responds to a government request, analyzes public policies and solutions in four European countries (Germany, Netherlands, United Kingdom and Sweden). It identifies the courses of action to accelerate the energy renovation of buildings in France.
Based on the contributions of these complementary expertises, we have raised a few key questions: What is the future for construction and renovation in France in terms of energy? What are the main points to be retained from the different scenarios and action plans to achieve the French objectives of “carbon neutrality” by 2050, in the building sector? What are the main obstacles, levers and solutions for better energy performance in the residential and commercial sectors?
To find out more, see our report: