Swiss Registry Introduces Biochar Certification for Concrete Applications

Carbon Standards International (CSI), a Switzerland-based registry, has launched version 3.1 of its Global Biochar Carbon Sink (C-Sink) standard, expanding its scope to include biochar used in concrete. This update opens new avenues for long-term carbon storage through innovative construction practices.

A modern concrete building surrounded by green deciduous trees. Ai generated picture.

The revised standard allows biochar incorporated into concrete to earn C-Sink 1000+ credits, reflecting carbon sequestration of up to 1,000 years with 75% of the carbon retained. Additional certification tiers include C-Sink 100, which guarantees 17.1% carbon storage for 100 years, and C-Sink 60, offering temporary sequestration for up to 60 years.

CSI highlighted the role of durable building materials like cement, lime, clay, gypsum, and geopolymers in creating stable matrices for biochar storage. These materials ensure carbon retention, whether reused in construction or deposited in soil, reinforcing the environmental benefits of biochar-enhanced concrete.

The updated standard applies to biochar certified under the European Biochar Certificate or World Biochar Certificate, ensuring high-quality and globally recognised methodologies. Version 3.1 is now available, aiming to accelerate biochar adoption in construction and contribute to advancing global carbon reduction efforts.