We are proud to present to the world the revised 2024 edition of the Puro Standard Geologically Stored Carbon Methodology, which contains the requirements to issue CO2 Removal Certificates (CORCs), Puro.earth’s carbon credit, from bio-CCS and DAC+Storage carbon removal activities. In further aligning the methodology with the latest scientific research and the Integrity Council for the Voluntary Carbon Market (ICVCM) Core Carbon Principles (CCP) we made important revisions. The 2024 edition includes major changes in project eligibility, as well as requirements for the storage reservoirs. Other changes relate to biomass sourcing criteria, carbon accounting, data collection and monitoring requirements. In this blog post, we summarize the key updates and the reasons behind them. 

Geologically Stored Carbon (GSC) refers to the overall process of storing carbon dioxide (CO2) in underground geological formations for the purpose of permanent CO2 removal. In the Puro Standard GSC methodology, the stored CO2 must come from: 

a) the atmosphere (i.e. separation of CO2 directly from the atmosphere via sorbents, known as Direct Air Capture (DAC)), or 
b) the processing of sustainably sourced biogenic materials (e.g. CO2 from bioenergy plants (BECCS), fermentation facilities, etc.). 

The GSC methodology covers DACS and BECCS, methods that have been included in multiple climate scenarios by the IPCC and others, due to their potential to produce very high volumes of removals. For properly managed sites, GSC removal is safe and efficient as there is a lot of experience and mature technology around the globe. Moreover, there are strong regulatory frameworks in place in several jurisdictions, such as the US, Canada, the UK and EU. With this methodology, the Puro Standard gives the carbon markets a high integrity pathway to validate carbon removal activities from these methods in order to incentivize investment and operationalization.

We are very grateful to all who participated in the public consultation and revision of this methodology. Your contribution was valuable. The numerous reviewers have made this methodology the cutting-edge methodology for geologically stored carbon in the carbon markets.

The public consultation comments – numbering over 235 – and our responses are available here.

Key updates in the methodology

• Eligible sources of CO2: Carbon containing substances, such as bio-oil, are now excluded 
We decided to focus on CO2 and exclude carbon containing substances, such as bio-oil, because their physical behavior would require different storage requirements, carbon accounting rules and would make auditing less straightforward. Instead, we require that the stored CO2 be at least 95% pure. This aligns with the EU CCS directive requirement that the stored substance consists “overwhelmingly of CO2”.

• Eligible capture and storage processes: Enhanced Oil Recovery (EOR) and co-burning of coal and biomass are now excluded
In alignment with the ICVCM CCPs criterion 13, we also banned capture and storage processes that are not compatible with net-zero goals. Examples of these are BECCS facilities that co-burn coal and biomass for energy production and Enhanced Oil Recovery (EOR).

• Crediting period set to 15 years
We have extended the crediting period for the Geologically Stored Carbon (2024) methodology to 15 years from the previous 5 years. This is fulfilling the need for certainty of projects with high capital expenditure and a long operating timeline. Also, we considered that the carbon removal baseline would be static over 15 years and we confirmed that this was in line with the “Article 6.4 activity standard for projects” (A6.4-STAN-AC-002) as a point of reference.

• Baseline scenarios and leakage
In alignment with the latest Puro Standard general rules (version 4.0), which now prescribes a three-step approach to accounting for leakage, we now require the carbon removal supplier to identify and characterize leakage sources, to mitigate them and to quantify and account for unmitigated leakage sources. Included now are negative ecological leakage, market leakage and activity shifting leakage. 

• Quantification of CORCs 
Measurement requirements for the quantification of CO2 Removal Certificates (CORCs) have been made more explicit. Uncertainty assessment and reporting has been strengthened and leakage burdens have been included in the calculations. 

• Life Cycle Assessment (LCA) requirements 
Significant detail has been added to the Life Cycle Assessment (LCA) requirements, to guide how the assessments should be done, what processes to include and how to calculate emissions. 

• Biomass sustainability criteria
Biomass sourcing criteria were refined, including corrections to certain criteria formulations. The scope of biomass feedstock categories was expanded (waste) and there are now 15 categories. For each category, sourcing criteria are defined in terms of traceability (origin and type) and sustainability of production. 

Multiple options are now given to demonstrate biomass sustainability criteria (e.g. certification, regulatory compliance, primary evidence). Additional rules specific to bio-CCS apply in the methodology, for example, with respect to baseline and leakage.

 
• Data collection and monitoring
We significantly increased the level of detail in specific parameters to monitor at different stages of the removal activity, such as capture, transport, injection, and post-injection.

• Risk assessment and management criteria
Risk assessment criteria and the mitigation requirements when a risk has realized are now more detailed, such as monitoring CO2 release and reversal during and post closure of the injection project.

Download the 2024 Edition GSC methodology document here

Download the Biomass Sustainability Criteria here

Are you ready to include carbon removal in your climate actions?
If you are a project developer or potential supplier of Geologically Stored Carbon removal, get started here.
If you are interested in buying CORCs from a Geologically Stored Carbon project, contacts us here.