Alkalinity Generation Constraints on Basalt Carbonation for Carbon Dioxide Removal at the Gigaton-per-Year Scale

Tutolo, Benjamin M; Awolayo, Adedapo; Brown, Calista

Alkalinity Generation Constraints on Basalt Carbonation for Carbon Dioxide Removal at the Gigaton-per-Year Scale

dc.contributor.author	Tutolo, Benjamin M
dc.contributor.author	Awolayo, Adedapo
dc.contributor.author	Brown, Calista
dc.date.accessioned	2021-09-20T22:42:40Z
dc.date.available	2021-09-20T22:42:40Z
dc.date.issued	2021-08-20
dc.description.abstract	The world adds about 51 Gt of greenhouse gases to the atmosphere each year, which will yield dire global consequences without aggressive action in the form of carbon dioxide removal (CDR) and other technologies. A suggested guideline requires that proposed CDR technologies be capable of removing at least 1% of current annual emissions, about half a gigaton, from the atmosphere each year once fully implemented for them to be worthy of pursuit. Basalt carbonation coupled to direct air capture (DAC) can exceed this baseline, but it is likely that implementation at the gigaton-per-year scale will require increasing per-well CO2 injection rates to a point where CO2 forms a persistent, free-phase CO2 plume in the basaltic subsurface. Here, we use a series of thermodynamic calculations and basalt dissolution simulations to show that the development of a persistent plume will reduce carbonation efficiency (i.e., the amount of CO2 mineralized per kilogram of basalt dissolved) relative to existing field projects and experimental studies. We show that variations in carbonation efficiency are directly related to carbonate mineral solubility, which is a function of solution alkalinity and pH/CO2 fugacity. The simulations demonstrate the sensitivity of carbonation efficiency to solution alkalinity and caution against directly extrapolating carbonation efficiencies inferred from laboratory studies and small-injection-rate field studies conducted under elevated alkalinity and/or pH conditions to gigaton-per-year scale basalt carbonation. Nevertheless, all simulations demonstrate significant carbonate mineralization and thus imply that significant mineral carbonation can be expected even at the gigaton-per-year scale if basalts are given time to react.	en_US
dc.identifier.citation	Tutolo, B. M., Awolayo, A., and Brown, C. (2021). Environmental Science and Technology, 55(17), 11906-11915. DOI: 10.1021/acs.est.1c02733	en_US
dc.identifier.doi	http://dx.doi.org/10.1021/acs.est.1c02733	en_US
dc.identifier.issn	0013-936X
dc.identifier.issn	1520-5851
dc.identifier.uri	http://hdl.handle.net/1880/113905
dc.identifier.uri	https://doi.org/10.11575/PRISM/46142
dc.language.iso	eng	en_US
dc.publisher.department	Geoscience	en_US
dc.publisher.faculty	Science	en_US
dc.publisher.institution	University of Calgary	en_US
dc.rights	This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science & Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.est.1c02733 Unless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.	en_US
dc.subject	Fluids	en_US
dc.subject	Basicity	en_US
dc.subject	Inorganic carbon compounds	en_US
dc.subject	Minerals	en_US
dc.subject	Aquifers	en_US
dc.title	Alkalinity Generation Constraints on Basalt Carbonation for Carbon Dioxide Removal at the Gigaton-per-Year Scale	en_US
dc.type	journal article	en_US
ucalgary.item.requestcopy	true	en_US
ucalgary.scholar.level	Faculty	en_US