In a new study published in Biomass & Bioenergy, Prof. David Chiaramonti and colleagues from the Polytechnic of Turin, the University of Pisa, and collaborating European research institutes put a common assumption to the test: can standard soil sampling really tell us how much carbon from biochar stays locked in the ground?
In a tightly controlled 75 m² test plot, the answer was no. Lab results didn’t match the known carbon added: measured Soil Organic Carbon (SOC) came out higher than what was actually put in, revealing built-in errors from where you sample, how little soil the lab actually measures, and how unevenly biochar pieces spread in soil. Even with careful tillage and many samples, the numbers swung too much to support bankable credits.
Why it matters: In the EU, the climate credit is counted using e_SCA (“emissions from Soil Carbon Accumulation”) under the Renewable Energy Directive II – Implementing Regulation (RED II-IR). Internationally, a similar credit called F_SCA is used (same idea, different program).
F_SCA works much like e_SCA, but the rules aren’t identical. It’s used by the International Civil Aviation Organization (ICAO) for Sustainable Aviation Fuel (SAF).
Under RED II, you must take soil cores and lab-test them to put a number on soil carbon gains from biochar (that becomes the e_SCA credit). By contrast, ICAO’s Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) and the draft European Union Carbon Removal Certification Framework (EU-CRCF) don’t insist on soil sampling. They require: (a) full characterization of the biochar (including the durable carbon fraction), (b) proof it was incorporated into soil, and (c) independent third-party auditing of the deployment.
Want the details, figures, and tables?
Check the full paper.
About
David Chiaramonti is Mechanical Engineer, PhD in Energetics, Full Professor at the Polytechnic of Turin, “Galileo Ferraris” Energy Departmet (DENERG).
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