Issues in ERW certification
On 10 November 2026, Cerulogy and ICF presented this paper on issues in ERW certification at the 12th meeting of the EU Carbon Removal Expert Group.
Review of carbon removals by direct ocean carbon capture and storage (EU CRCF)
Direct ocean carbon capture and storage (DOCCS) is a carbon dioxide removal method in which the pH of seawater is manipulated to extract carbon which can then be stored (e.g. through geological CCS). The seawater experiences a carbon deficit and draws CO2 out of the atmosphere. Typically, electrochemistry is used to separate seawater or brine into acid and base parts; the acid part is used to acidify seawater drives off CO2 for capture, and the base part is then mixed back in to restore alkalinity. This technical review presents the underlying chemistry, technologies, efficiency impacts, and sustainability implications of DOCCS.
The review was led by Martin Johnson (Ecodiversity), with key contributions from Cerulogy and Zara Popstoyanova (ICF). Its findings were presented alongside evidence from external experts and from the CRCF Expert Group on Permanent Carbon Removals at a European Commission workshop.
Review of carbon removals through mineral carbonation (EU CRCF)
This technical review concerns the sequestration of CO2 in the form of solid carbonate minerals, a process referred to as mineral carbonation. We focus in particular on cement-based building materials, but also consider alkaline industrial by-products such as metallurgical slags that contain calcium oxide or calcium hydroxide, and mine tailings containing silicates and other alkaline compounds. These materials carbonate naturally when exposed to atmospheric CO2 and moisture; ‘enhanced carbonation’ is where the process is sped up by active intervention, and this could be a candidate for recognition under the CRCF. The review covers the underlying chemistry of carbonation, the environmental factors that influence its rate, and the critical challenge of quantifying the natural carbonation baseline.
The review was conducted by Cerulogy, and was presented alongside evidence from external experts and from the CRCF Expert Group on Permanent Carbon Removals at a European Commission workshop.
Golden Cropportunity? Intermediate crops and crops grown on severely degraded land
In 2024, the European Commission added two crop-based biofuel feedstock categories to ‘Annex IX’ of the Renewable Energy Directive (RED): this categorises them among the most sustainable biofuel feedstocks and confers special incentives for their production and use. The two new feedstocks are (i) crops grown between the main harvests on agricultural land, and (ii) crops grown on severely degraded land; bringing them onto Annex IX could be justified by an assumption that these crop production methods don’t compete with the food market and don’t stimulate agricultural expansion.
In this report for Transport and Environment, we examine this assumption and explore the sustainability issues that are not managed by current regulation. We focus on oilseed crops, which are likely to be in high demand in aviation, shipping, and road sectors in 2030 and beyond, and characterise types of oilseed that are suited to either of the above production systems. These often have the potential to bring agricultural and even ecological advantages; but adoption of these new production systems is far from risk-free, and suffers from many of the same ecological and environmental hazards as other forms of agricultural intensification.
We estimate the lifecycle emissions of biofuels produced from these crops following examples from the literature, and find that they are highly sensitive to the rate of use of agricultural inputs. Using GIS tools, we map potentially eligible growing areas in the EU in order estimate plausible production potentials for compliant feedstock. These fall short of the demand expected to arise from EU transport decarbonisation targets, implying that the EU’s targets could not be met using domestic feedstock only.
Review of carbon removal by ocean alkalinity enhancement (EU CRCF)
Ocean alkalinity enhancement (OAE) is a carbon dioxide removal method utilising carbonate chemistry to store CO2 as dissolved inorganic carbon (DIC) in the ocean. The ocean already durably stores a huge quantity of DIC due to its high alkalinity, driven by natural rock weathering. However, quantification and certification for engineered OAE activities present challenges due to the large spatial and temporal scales on which CO2 uptake from the atmosphere occur, the need for modelling to quantify removals, and the need for research and monitoring of ecological side-effects. This technical review for the European Commission explores these issues.
The review was led by Martin Johnson (Ecodiversity), with key contributions from Cerulogy and from Zara Popstoyanova (ICF). It was presented alongside contributions from experts in the field at a European Commission carbon removals workshop on ERW and OAE.
Review of carbon removals through enhanced rock weathering (EU CRCF)
Enhanced rock weathering (ERW) seeks to sequester carbon dioxide as dissolved inorganic carbon (DIC) by accelerating the dissolution of alkaline minerals on the Earth’s surface. This technical review explores ERW in the context of the EU’s Carbon Removals and Carbon Farming Regulation (CRCF), and covers the theoretical underpinnings in geochemistry and soil science, implementation challenges, quantification & baselining issues, and sustainability safeguards that would have to be considered if an ERW methodology were to be developed for the CRCF.
The review was led by Cerulogy, with key contributions from Zara Popstoyanova (ICF) and Martin Johnson (Ecodiversity). It was presented alongside evidence from experts in the field at a European Commission carbon removals workshop on ERW and OAE.
European Commission carbon removals workshop: DOCCS and mineral carbonation
Cerulogy delivered a European Commission workshop on two carbon removal activities, in partnership with ICF and Ecodiversity. Direct ocean carbon capture and storage (DOCCS) encompasses a number of technologies that extract carbon dioxide from seawater for eventual geological storage. Mineral carbonation involves the absorption and permanent binding of carbon dioxide into materials (concrete and alkaline industrial wastes) in the form of solid carbonates.
The one-day workshop took place on 09th February 2026 with the goal of gathering input from experts and stakeholders to inform the CRCF process. Cerulogy and Ecodiversity presented technical reports that provided an overview of how the carbon removal pathways work, challenges in implementation, issues around quantification and baselining, and potential sustainability impacts. Experts from academia and industry presented on specific topics, and participated in discussions.
Delegated Regulation on DACCS, BioCCS, and biochar carbon removals under the EU’s CRCF
The Commission adopted Delegated Regulation (EU) 2026/285 on 3 February 2026. The Delegated Regulation lays down detailed methodologies for three carbon removal activities under the EU’s Carbon Removals and Carbon Farming Certification Framework (CRCF): these are direct air capture with carbon storage (DACCS), biogenic emissions capture with carbon storage (BioCCS), and biochar carbon removal (BCR). The regulation, which was developed with the support of Cerulogy and ICF, sets out the full technical architecture for certification: eligibility criteria, activity and monitoring periods, baseline rules, quantification of removals and associated emissions, long‑term storage and liability requirements, sustainability safeguards for biomass, and monitoring and reporting obligations. DACCS and BioCCS must use geological storage permitted under the CCS Directive, while BCR must demonstrate the fraction of biochar that is considered stable.
Updated evidence on ‘high indirect land-use change risk’ biofuel feedstock
Between 2020 and 2024 Cerulogy supported Guidehouse, GRAS and IIASA in updating the evidence base on the deforestation associated with biofuel feedstock crops, as an input to the European Commission’s assessment of which biofuel crops pose a high indirect land-use change (ILUC) risk. The work includes new satellite data analysis demonstrating the continued linkage between some biofuel crops and deforestation – notably oil palm in Southeast Asia and soybeans in South America.
This technical analysis has informed a proposal by the Commission to update the EU’s list of high ILUC-risk feedstocks to include soybeans.
European Commission carbon removals workshop: ERW and OAE
Cerulogy delivered a European Commission workshop on two carbon removal technologies, in partnership with ICF and Ecodiversity. The ocean is the Earth’s largest reservoir of carbon (in the form of dissolved inorganic carbon, or DIC): by adding alkalinity to the Earth’s surface, watercourses and/or oceans, enhanced rock weathering (ERW) and ocean alkalinity enhancement (OAE) seek to augment this reservoir and stimulate net draw-down of carbon dioxide from the atmosphere.
The one-day workshop took place on 25th September 2025 with the goal of gathering input from experts and stakeholders to inform the CRCF process. Cerulogy and Ecodiversity presented technical reports that provided an overview of how the carbon removal pathways work, challenges in implementation, thorny issues around quantification and baselining, and potential sustainability impacts. Ten ERW/OAE experts from academia and industry presented on specific topics, and participated in discussions.
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Issues in ERW certificationNovember 10, 2026
