Bio-based construction materials
This methodology focuses on projects producing construction materials derived from renewable biological resources. Accounting for full life cycle emissions and biogenic carbon storage, it guides projects on precise removal calculations.
Eligible technologies
Eligible biobased construction materials are those derived from organic, renewable sources like plants, trees, and agricultural byproducts, which inherently contribute to reducing greenhouse gas emissions by absorbing carbon dioxide during their growth.
This category of materials encompasses a wide variety of biomass, including wood (timber or lumber), bamboo, hemp, straw, recycled paper, and flax.
The application of these materials is diverse, ranging from traditional uses, such as in wood construction, to more innovative applications like mycelium-based insulation and cellulose nanocrystals. These materials represent a spectrum of options for construction, each offering the potential for carbon-neutral or even carbon-negative solutions in building projects.
European context
Few official figures exist, but it is clear that biobased construction is not the norm, and would benefit from carbon credits to scale up. For example, in France an estimated 10% of residences are built with wood, and 7% of wall insulation renovations were done with biobased materials. In the Netherlands, only 2% of construction is wood-based, and 0.1% of construction uses other biobased materials.
There are clear regional preferences for the types of building material used, based on material availability, traditional architecture style, technical know-how, and local climate. For example, in Germany and Belgium walls are mostly constructed with clay blocks. These are rarely used in the Netherlands or the UK, where instead calcium silica and concrete are mostly used. Use of timber in construction varies widely across European countries, with countries like Spain and Cyprus using the least, and Norway and Estonia using among the most.
Permanence
Permanence is a particularly important criteria for removal credits issued from biobased construction. Biobased materials with an expected service lifetime of 100 years or more are eligible for carbon removal credits. Expected service lifetimes are provided by project developers, and are typically displayed in Environmental Product Declarations (EPDs).
For composite materials made of multiple components with different lifetimes, the lifetime of the final product will be used, even if some components have technically longer lifetimes. Projects may petition to exceptionally consider a longer lifetime for one component if they can prove that the component will be reused or recycled.
All biobased construction materials are eligible for avoidance credits, which are not subject to permanence criteria and do not have a threshold lifetime duration.
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