SBTi Buyers Guidance
Integration of Carbon Lock Origin Certificates (CLOCs) within Corporate Net-Zero Strategies
Last modified: 14.11.2025
Purpose
This Guidance Note provides direction for corporate buyers seeking to utilise Carbon Lock Origin Certificates (CLOCs) issued under the Clo Carbon Cymru Biochar Standard in a manner consistent with the Science Based Targets initiative (SBTi) Corporate Net-Zero Standard v2 (Consultation Draft, 2025).
It explains how CLOCs can contribute to corporate net-zero targets while maintaining integrity, transparency, and alignment with SBTi’s high-quality carbon removal principles.
Nature of the CLOC unit
Each CLOC represents one tonne of verified carbon dioxide (CO₂e) removed from the atmosphere through the production and utilisation of biochar derived from biomass grown in existing farm woodlands, hedgerows and newly-established areas of agroforestry in Wales.
● Carbon is durably stored within biochar with a demonstrated half-life of >100 years.
● Verification follows ISO 14064-3:2019, ensuring independent, third-party assurance.
● Permanence testing applies Isometric Biochar Production and Storage Protocol (Version 1.1, 2025) stability parameters: H/C₍org₎ < 0.4 and random reflectance ≥ 0.6%.
CLOCs are registered, traceable, and retired upon verified use in soil or other stable storage applications.
Compatibility with SBTi Corporate Net-Zero Framework
Under the SBTi Corporate Net-Zero Standard v2, durable carbon dioxide removals may be used by companies only to neutralise residual emissions after achieving deep internal emission reductions. CLOCs are therefore eligible for use as neutralisation credits within the SBTi framework, provided they meet the following criteria:
● Verified removal of atmospheric CO₂
● Storage durability ≥ 100 years
● No double counting
● Transparent disclosure of project data and verification results.
Clo Carbon Cymru’s MRV and LCA procedures meet these criteria through ISO-aligned quantification, permanent retirement, and full registry transparency.
Appropriate Use of CLOCs within Corporate Climate Strategies
Companies purchasing CLOCs should:
1. Prioritise direct emissions reductions before applying CLOCs to neutralise residual emissions.
2. Disclose the volume of CLOCs used, year of retirement, and link to specifi c residual emissions (Scope 1, 2 or 3).
3. Avoid double claiming by ensuring the retirement is recorded solely within the CLOC registry.
4. Match CLOC vintages (year of carbon removal) to the corresponding reporting year for emissions neutralisation.
5. Reference the CLOC protocol (Biochar Standard Version 5, November 2025) in sustainability or annual reports.
Clo Carbon Cymru can provide verification documentation and registry confirmation letters for corporate ESG reporting.
Recommended Reporting Language
For annual sustainability or climate reports, companies may use the following wording:
[Company Name] achieved partial neutralisation of residual Scope [X] emissions through the purchase and retirement of Carbon Lock Origin Certificates (CLOCs) issued under the Clo Carbon Cymru Biochar Standard (Version 1, 2025). Each CLOC represents one tonne of verified, durable carbon dioxide removal in accordance with ISO 14064-2:2019 and the SBTi Corporate Net-Zero Standard (Consultation Draft, 2025).
Future Updates and Policy Alignment
The SBTi Corporate Net-Zero Standard v2 remains under consultation (2025–2026). Clo Carbon Cymru participates actively in this process and commits to updating this guidance and the Biochar Standard to maintain full compliance with the final published criteria. Buyers will be notified of any substantive changes affecting credit classification, reporting, or eligibility.
Contact us
For further guidance, verification records, or registry access:
Clo Carbon Cymru LTD – info@clocrbon.cymru – www.clocarbon.cymru