An interdisciplinary approach for advancing the use of biochar in buildings

The International Energy Agency highlights that buildings are critical for climate action, yet the sector is not on track for net zero by 2050. Achieving full decarbonisation presents major challenges, requiring bold approaches to reduce and offset emissions. Biochar, a carbon-rich by-product of biomass pyrolysis, can be used in building applications due to its carbon sequestration potential. Although awareness of biochar has grown, it is still not used at scale, and its potential remains underexploited. This research investigates the use of biochar in buildings through an interdisciplinary approach integrating social science, civil engineering, and building modelling. The aim is to deepen understanding of the physical and mechanical properties of biochar-cementitious composites, quantify their energy and carbon-saving potential across different building archetypes, and integrate multistakeholder insights.

The paper presents results from the first stakeholder workshop, which identified biochar feedstocks suitable for buildings and opportunities for integrating biochar into construction materials and building elements. These insights informed the initial biochar–concrete characterisation for non-structural elements using forestry waste feedstocks. In parallel, building simulations were conducted to evaluate potential energy savings. Material characterisation showed a 14% drop in compressive strength of biochar-concrete when 10% biochar was incorporated, and at 50% offers modest operational energy and carbon savings. These results inform the second stakeholder consultation, where the Delphi method is being used to confirm the key properties required to optimise biochar-concrete. The paper sets out how interdisciplinary methods can deliver meaningful insight into technology performance and a holistic understanding of biochar’s challenges and opportunities in buildings.