| A | B | C | D | E | F | |
|---|---|---|---|---|---|---|
1 | Name of methodology/standard | Methodology ID: | RBW-BICRS-CS-MSSB-V1.0 | |||
2 | Public consultation collected comments and responses | Public Consultation period: | 07/02/2025-10/03/2025 | |||
3 | Author | Comment | Type | Riverse response | Implemented? | Status |
4 | Anne "Liz" Ware- National Renewable Energy Laboratory | In the very beginning: “% Organic Content” – you mean organic carbon content? | Editorial | Yes we did, thank you we changed this. | Yes | Validated |
5 | Anne "Liz" Ware- National Renewable Energy Laboratory | Ocean current or upwelling requirements? Monitoring of Sediment Mixing processes? https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2019.00677/full Seismicity? – You speak to some of these in the appendix but don’t outline any specific requirements for expected/acceptable values. | Technical | Our choice of 2+ meters below the seafloor is guided by the results of a compilation of seafloor scouring depths from the action of ocean currents (Appendix C). The only risk created by seismicity would that liquifaction could disturb deposits. Obermeier 2009 says that earthquakes must be stronger than 5.5 to create liquifaction. This is a USGS tool for searching earthquake history in a region. Within 200 km of our project site in Louisiana, for example, there has never been recorded (since 1900) an earthquake of magnitude 5.5+. I think until we study the risk liquifaction poses to deposits, we could set this threshold and refer to the USGS earthquake database for project by project screening. | No | Validated |
6 | Anne "Liz" Ware- National Renewable Energy Laboratory | Heavy metal content of biomass? (i.e., some ag wastes can have higher metals, As in rice hulls for example) | Technical | We added the following requirement to the Environmental and Social Do No Harm requirements: Project Developers shall measure heavy metal content from biomass samples and demonstrate that it is below thresholds set by the relevant jurisdiction. | Yes | Validated |
7 | Anne "Liz" Ware- National Renewable Energy Laboratory | Baseline is 0 – appropriate? Counterfactual for biomass is assumed to fully return to atmosphere (needs to be proven?)? | Technical | The counterfactual/baseline removals from biomass are considered in the Biomass Feedstock module. Indeed we may consider a fraction of biomass carbon being permanently stored in the soil, it the alternative use is being left on the field to decompose. | No | Validated |
8 | Anne "Liz" Ware- National Renewable Energy Laboratory | Also, can you measure/monitor the rate of natural carbon accumulation over time (ie, 1000 years) of seabed for specific project anyway or is that assumed/modeled and should it be required? | Technical | There is organic carbon being buried in this environment constantly. The average carbon stock of marsh sediments is 23 kg in the upper meter (Maxwell et al. 2023), and the average carbon stock in shelf sediments is 10 kg in the upper meter (Atwood et al. 2020). MSSB has the potential to raise this carbon stock by a factor of 2-10x. Such injections only add to the carbon stock, and the carbon burial that would happen in the ensuing 1000 years will continue anyway. Nevertheless, we have modified the quantification approach and will now issue credits based on the modeled results from oxic environments (which will assume around 8% degradation), so there is minimal risk of crediting the project for removals that would have occurred anyway. | Yes | Validated |
9 | Anne "Liz" Ware- National Renewable Energy Laboratory | Is it possible there are carbon emissions associated with disruption (mixing) that need to be accounted for during project deployment? | Technical | MSSB's injection-based approach minimizes disturbances to the surface layer and surface sediments. Surface disturbance is prohibited by regulatory framework, so operational protocol includes measurements that monitor for turbidity and sediment resuspension. Minimal disturbance of surface sediments prevent emissions from this nature related to the project. | No | Validated |
10 | Anne "Liz" Ware- National Renewable Energy Laboratory | Still not sure exactly how this is done, Sinkco not very descriptive, understand if not able to share more tech description but knowing how this biomass actually gets in ocean sediment several meters deep would help elicit more robust feedback, especially related to the language that I think needs to be clarified: “Storage must be done in existing accessible marine sub-sediment. Projects that drill, dredge or build wells for the sole purpose of accessing sub-sediments or creating sub-sediment conditions are not eligible, due to the associated environmental risks.” – is drilling down to subsediment not what Sinkco is doing (making a specific marine subsediment area a CDR site)? Or are you referring to creating a previously not marine landscape into a marine landscape? Otherwise how do you get the biomass down there without something like drilling? Are there projects that are coupled to enable deployment and how do boundaries get drawn? Just not clear on what this language means myself | Technical | Indeed drilling isn't the right word because there's no rotation or cutting of anything, we have replaced this with excavate. Indeed we avoided describing the parter Sinko's technology in too much detail because, although the methodology is inspired by their project, we want the methodology to remain open to any other similar innovations that meet the same strict criteria. For Sinkco, biomass is delivered into shallow depths in sediments by penetrating soft sediment with a vibration-tipped lance. No drilling is required. | Yes | Validated |
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