Carbon Dioxide Removal from Air using Seafloor Peridotite
Abstract
We describe a method for Carbon Dioxide Removal from Air (CDR) using CO2 uptake via mineral carbonation, about half the cost of that proposed by Kelemen & Matter [1,2]. Reaction of CO2-bearing fluids and gases with peridotite rapidly forms inert, non-toxic carbonate minerals. In proposed methods for combined capture and storage of ambient CO2 via reaction of seawater or ground water with peridotite [1-5], return of depleted water to the surface draws down CO2 from air. Because they use available chemical and thermal energy that drive spontaneous natural reactions, they may be the least expensive methods for capture of CO2 from air. We focus on subsurface CO2 uptake during flow of surface water through fractured peridotite. Previously [1-3], we envisioned a design similar to enhanced geothermal systems (EGS), involving two large diameter boreholes, subject to the challenges of achieving rapid, efficient return flow that limit the success of EGS. Recent discussions yielded a less expensive, more robust design: A single well produces ambient, CO2-depleted pore water from seafloor peridotite. Such water has low carbon and high pH [6,7,8]. Where such waters are delivered to the surface, observations reveal rapid CO2 uptake from air [1,3,8-10]. Delivery to the sea surface would also reduce local acidification. Thermal buoyancy and pumps powered by wave and tidal energy would bring warm formation water from wells to the surface through conduits surrounded by colder seawater. Recharge would be via flow in natural or enhanced fracture networks in unconfined submarine aquifers. This method could be tested and scaled-up in coastal, sub-seafloor peridotite with onshore drilling off Oman, New Caledonia and Papua New Guinea, Spain, Morocco, USA, etc. It is possible to achieve much larger scale. Giant volumes of peridotite are exposed on the seafloor along slow-spreading mid-ocean ridges [3]. Robotic drills could install wells that deliver CO2-depleted water through fabric tubes to the sea surface. Does anyone know James Cameron's phone number? [1] Kelemen & Matter PNAS 08 [2] Kelemen & Matter AGU Fall 14 [3] Kelemen et al AREPS 11 [4] Wilson et al IJGHGC 14 [5] Schuiling & Krijgsman Climate Change 06 [6] Barnes & O'Neil GSA Bull 69 [7] Kelley et al Science 01 [8] Paukert et al Chem Geol 12 [9] Mervine et al GCA 13 [10] Mervine et al Chem Geol 15
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMGC21J..07K
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGEDE: 4806 Carbon cycling;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICALDE: 6620 Science policy;
- PUBLIC ISSUES