What will be the place of biobased sources in construction by 2030?

The recent arbitrations of the RE2020 have put biobased materials on the front of the stage: but what will be the place of biobased materials in construction by 2030? Are the sectors sufficiently mature and developed to respond to the expected trajectory? Will we be able to make room for these materials (some resulting from ancestral practices), in a coherent carbon cost equation?

The hub of low-carbon prescribers sought to provide answers to these questions by analyzing the challenges of carbon accounting, and by drawing up an objective panorama of biobased sectors, their decarbonisation potential and best practices.

A call for innovation was also launched to offer a real sector innovation book.

The key messages of the biobased sector brief as well as the results of the call for innovations will be shared on June 29 from 14:30 p.m. to 16:30 p.m. during a webinar for the general public. Already more than 1000 registered.

A transformation of practices

The development of biobased sources is first and foremost a matter of practices. The building industry has been structured in recent years mainly around a few materials, for example wood today occupies around 8% of the construction market share in France. To make room for biobased sources, an entire industry and therefore the entire value chain will learn to design, produce and operate differently. A collective challenge that highlights the importance of not opposing materials, but rather to aim for a plural performance: technical, economic and low carbon.

Bio-based, low carbon champions through substitution effect

Resulting from low energy and carbon intensive processes, the use of biobased materials in construction allows a very significant carbon benefit by substitution effect compared to conventional products (and this without taking into account the carbon storage effect, nor of the methodological advantage linked to dynamic LCA). Their use allows less use of energy-intensive materials and fossil fuels.

The second carbon benefit associated with biobased materials is their temporary carbon sequestration. For example, wood thus stores around 1 tCO2e / m3 of wood.

However, the impact of biobased materials on carbon sinks varies depending on the management of the resource, the lifespan of the materials and the time horizon studied. Criteria on resource management and on the use of materials make it possible to optimize the sink effect. SNBC's success will be based on teamwork between sectors: building, industry, forest-wood-biomass, etc. SNBC has chosen to mobilize wood energy and biobased sources in building, in order to double the amount carbon reservoir (soil and materials) and divide GHG emissions by 6. In line with this strategy, RE2020 has taken decisions that lead to "more frequent use of wood and biobased materials". The hub of low-carbon prescribers has studied that a building falling within an SNBC trajectory will store in 2030 on average between 60 and 70 kgCO2e sequestered per m² built (collective housing and offices).

Multiple applications, varying levels of maturity

Bio-based materials have multiple applications: insulation, paint, panel components, concrete, etc. These materials nevertheless present operational issues which must be taken into account in the prescription (cost, technical characteristics, availability, insurability).

The call for innovation carried out shows that mature solutions, having all the necessary documents (Technical opinion or ATex, FDES), are already numerous on the market. A2C Préfa has, for example, designed a mixed prefabricated wood-concrete floor to reduce the carbon footprint of the floor. Gramitherm uses an abundant resource to make herbal insulation. Vicat offers an alternative concrete incorporating hemp.

Available resources and development to support

1st producer of fiber plants, and 3rd forest resource in Europe, France benefits from a strong potential on its territory. France is a real reservoir of resources which only asks to be encouraged and developed.

The analysis of the availability of this resource and the level of structuring of the sectors requires distinguishing two main categories: plant fibers and wood.

The availability of plant fiber resources is, ie expert enough, to cope with a significant increase; materials using in the great majority of cases a co-product which is little or not exploited.

The major stake of the wood sector is the articulation between the actors of the first and second transformation for a supply under good conditions on the French territory (costs, quality and deadlines). The increase in demand for timber is also likely to raise resource availability issues. To limit imports and develop French resources, the sector could be structured around hardwood (representing ¾ of French species) in addition to softwood, and specifiers should focus on these species.

In addition to the challenges of resources and transformation, the issue of training of actors emerges as a major axis to ensure optimal use of these materials. Building biobased indeed requires knowledge and mastery of their specificities, to exploit their strengths while ensuring an optimized design both qualitatively and economically.

New practices to be assimilated for cost optimization

Several studies have been carried out by the Hub on the cost-carbon equation of biobased sources. These made it possible to observe certain economic trends, in particular for wood construction:

• Single-family houses with no observed trend of additional costs (we note, however, that the services of houses in timber construction are sometimes with very qualitative service levels, which can generate bias in the comparisons),
• Collective housing with additional costs of 5 to 10% but up to 15-20% depending on the height of the building.
• Costs in tertiary buildings that are difficult to extrapolate, given the diversity of the projects and their emblematic characteristics, which do not make it possible to identify rules that can be generalized.

The use of mixed constructions or all wood can be considered as a new practice, with market shares and a still small number of insiders. Building biobased requires knowledge and mastery of their specificities to exploit their strengths while ensuring a controlled design, implementation and operation. The training of actors is therefore a major axis to ensure optimal use of these materials. This is necessary at all levels: project owners, architects, design offices, companies, etc.

The assimilation of practices by a growing number of actors will make it possible to increase the use of these materials in construction, and their competitiveness throughout the value chain (economy of scale for production costs, optimization of design and implementation), which should allow the sector to be all the more competitive on a cost-carbon approach.

According to Christophe Rodriguez, Deputy Director General at IFPEB, “The RE2020 is an unprecedented regulation that propels construction on the path to carbon neutrality. The hub for low-carbon prescribers is a community that wants to share, acquire operational tools and learn to anticipate and make these changes a success for all building sectors. The analyzes we are carrying out show us that the cards will be reshuffled but also that each solution, each material can play a role. The condition of our environmental transition will be the innovation capacity of the sectors. Our next briefs will concern the technical packages and the building envelope. "

The key messages of the concrete brief as well as the results of the call for innovations will be shared on June 29 from 14:30 p.m. to 16:30 p.m. during a consumer webinar.