The “Global Rock C-Sink” certification guidelines by Ithaka Institute (PDF) have been revealed on Oct thirty first 2022. It has not been formally introduced but, although (will occur in a number of weeks). Our issues for rocks and soils are talked about there, too. The primary certificates for the CDR from our undertaking have been issued by q.inspecta on Nov 2nd 2022.
The brand new certification methodology considers the precise nutrient and trace-element content material of the deployed rock mud, in addition to the sector’s soil traits, to make sure software charges which are secure and useful for the agricultural system and in accordance with all related European laws. It’s crucial that cropland-based ERW purposes are carried out in such a framework, have solely optimistic results to the agronomic system and thus can absolutely be acknowledged as a useful agricultural observe – not as a CDR-focused burden to be carried by the farmers and the meals system. This basis is essential for acceptance and scalability.
Why is third-party certification necessary?
We’re involved that tasks with dangerous status would possibly harm the belief of the general public in ERW usually. In our view subsequently it’s vital for the credibility of bought certificates that the corporate who executes a CDR technique isn’t the one which certifies and validates the precise CDR and/or the one which creates the certificates and sells it. Each elements of the problem to scale up rock weathering, i.e. MRV on one facet and up-scaling on the opposite facet, have totally different methods/wants and are seemingly exhausting to mix in a single group responsibly because of conflicting pursuits (e.g. develop quick vs. measure precisely). For optimum governance separate establishments to us appear to be one of the best resolution.
Scientific follow-up by Undertaking Carbdown
We’re combining the pilot undertaking with our scientific efforts to measure ERW at Undertaking Carbdown. We’re utilizing in-field measurements, sampling and in depth pot/lysimeter experiments to observe up on the precise weathering charges within the cropland fields. The precise soils from the fields used on this undertaking shall be included in a big set of pot/lysimeter experiments in our greenhouse lab.
On this extensive greenhouse experiment beginning in winter 2022/2023 the weathering kinetics shall be assessed for every soil utilizing a number of measurement strategies to quantify captured CO2. These will embody analyses of weathering merchandise in leachate, quantifications of remaining rock within the soil in addition to measurements of fuel fluxes and precipitation of secondary minerals (which may probably cut back the quantity of captured CO₂ by as much as 50%), e.g. utilizing isotope analyses. The experiments are deliberate to run for twenty-four months or extra and can contain a whole lot of pots/lysimeters permitting us to higher perceive the uncertainty ranges in realized CDR-potential for various soil/rock combos and charges.
Optimized for velocity, not for economics
For this pilot undertaking we solely centered on demonstrating the present standing of ERW observe, involving all events from “cradle to grave”. To hurry up the undertaking we didn’t deal with cost-reducing optimizations. This resulted in a gross sales worth of about € 230 per tonne of CO₂. Many parameters, nevertheless, might be optimized.
We’re utilizing off-the-shelf Eifelgold “Brechsand” with grain sizes as much as 2,000 microns equipped by RPBL at a particular discounted worth per ton. Sooner or later rock value may very well be lowered e.g. through the use of low-cost, pelletized waste basalt dusts (there are a lot out there).
The principle value drivers stay the logistics: most of our fields have been 300-400 km away from the mine, one subject even 560 km, which isn’t superb in any respect. Prices (and CO₂ emissions) may very well be considerably lowered by selecting fields nearer to the mine or through the use of ships and trains as an alternative of vans for many of the transport, particularly for bigger quantities of rock. Lastly, we must always be capable of progressively decrease the carbon removing safety margins sooner or later via improved scientific understanding and thru knowledge being collected as we communicate, which may even affect pricing.
One of many causes to pick out Eifelgold basalt was avoiding delays because of pre-application lab assessments or approvals from authorities companies. We are able to confidently say that this undertaking is environmentally secure since we use a rock kind that has been licensed for fertilizer use within the EU for many years. Eifelgold is even listed within the allowed amendments for organic farmers in the Demeter group. However we’re monitoring for heavy metals, and so forth. in our follow-up lab/greenhouse experiments.
Selecting “Eifelgold Brechsand” made us quicker for this undertaking, however for future tasks it could be worthwhile to think about different rocks as nicely.
How is the quantity of saved CO₂ calculated?
The “Eifelgold” basalt has a theoretical CDR capability of 419 kg CO₂ per ton of rock. The theoretical CDR capability of a given rock might be expressed as a perform of its steel content material (alkali- and alkali-earth-metals). The employed technique is utilizing a nicely established formulation to calculate the theoretical CDR capability, primarily based on the belief of an incongruent launch of steel cations, solely contemplating calcium, magnesium, potassium and sodium (see certification guidelinesChapter 2.2.1).
Deploying totally different security elements and defining necessities to the agro-climatic situations of a land-unit to be admissible for rock powder purposes, the theoretical CDR capability is translated into an authorized Rock C-sink potential. The rules exclude land-units of agro-climatic situations fostering secondary clay formation, which might impede a full realization of the CDR capability, because of immobilization of metals (certification guidelines Chapter 3). A security issue of x0.9 is utilized to the CDR capability, addressing the remaining uncertainty ensuing from potential clay formation (certification guidelinesChapter 2.2.1). To deal with potential downstream losses of dissolved inorganic carbon, two extra security elements are utilized. To deal with the potential formation of persistent calcium carbonate a conservative security issue of x0.9 is utilized. Lastly, a security issue of x0.86 is utilized to account for the CDR effectivity as soon as dissolved inorganic carbon is reaching the ocean by way of riverine methods. Right here losses might be anticipated from oceanic carbonate equilibria (certification guidelinesChapter 6-6.1).
The CDR is licensed unbiased of the temporal dynamics of C sequestration, as for prevailing uncertainties concerning the precise carbon sink curve (certification guidelinesChapter 7-7.1).
