The rapid and cost-effective capture and subsurface mineral storage of carbon and sulfur at the CarbFix2 site

Abstract

One of the main challenges of worldwide carbon capture and storage (CCS) efforts is its cost. As much as 90% of this cost stems from the capture of pure or nearly pure CO 2 from exhaust streams. This cost can be lowered by capturing gas mixtures rather than pure CO 2. Here we present a novel integrated carbon capture and storage technology, installed at the CarbFix2 storage site at Hellisheiði, Iceland that lowers considerably the cost and energy required at this site. The CarbFix2 site, located in deeper and hotter rocks than the original CarbFix site, permits the continuous injection of larger quantities of CO 2 and H 2 S than the original site. The integrated process consists of soluble gas mixture capture in water followed by the direct injection of the resulting CO 2-H 2 S-charged water into basaltic rock, where much of the dissolved carbon and sulfur are mineralized within months. This integrated method provides the safe, long-term storage of carbon dioxide and other acid gases at a cost of US $25/ton of the gas mixture at the CarbFix2 site and might provide the technology for lower CCS cost at other sites.

An Overview of the Status and Challenges of CO2 Storage in Minerals and Geological Formations

“…In Phase I, ∼200 tCO 2 were injected at a depth of 500 m with a 100 m flow path through the basalt. New techniques were developed in both Phase I (Sigfusson et al, 2015) and Phase II (Gunnarsson et al, 2018) to inject water and CO 2 separately with proportions insuring the complete dissolution of CO 2 in water at depth. These techniques are very important, because they eliminate the need for an impermeable caprock and thereby greatly increases the number and extent of potential basalt storage reservoirs.…”

“…This offers the potential to recycle pore water for continued co-injection with CO 2 , and addresses concerns about the extent of water consumption for solution trapping methods. Moreover, Climeworks has installed direct air capture unit on site, to investigate the potential for the project to be carbon negative (Gislason et al, 2010;Aradóttir et al, 2011;Matter et al, 2011Matter et al, , 2016Snaebjörnsdóttir et al, 2017;Gunnarsson et al, 2018).…”

“…This has been implemented in the Carbfix Project in Iceland. There, more than 10,000 tons of CO 2 captured from geothermal steam is injected into subsurface pore space in basaltic lavas, where it is mineralized within a year (Gislason et al, 2010;Aradóttir et al, 2011;Matter et al, 2011Matter et al, , 2016Snaebjörnsdóttir et al, 2017;Gunnarsson et al, 2018). This approach is at a lower stage of technological readiness and is under continued investigation on the laband pilot-scales.…”

How (Carbon) Negative Is Direct Air Capture? Life Cycle Assessment of an Industrial Temperature-Vacuum Swing Adsorption Process

“…[10][11][12] Captured CO2 can be stored geologically or via mineralization. 13,14 However, DAC not only allows us to remove GHG emissions from our past use of fossil fuels. DAC also enables future fuels with a closed carbon cycle: The captured CO2 could serve as a carbon feedstock for fuels [15][16][17][18][19][20] , and also other value-added products like chemicals [21][22][23][24] and building materials [25][26][27] via carbon capture and utilization (CCU).…”

Zero-Emission Geothermal Power Generation: Experimental Study on Carbonate Mineralization through CO2-Andesitic Pyroclastic Rock Interaction at Oku-Aizu Geothermal Plant

“…In Iceland, sub-surface mineral storage of carbon and sulfur at the CarbFix site at 40-80 °C was reported to have been achieved. The CarbFix approach involves accelerating the mineralization of the acid gases (CO 2 and H 2 S) injected into the basaltic layers [10][11][12][13][14][15]. Basaltic rocks prove to be advantageous for the mineralization of CO 2 and other acid gases as they are relatively reactive compared to most of the other rock types.…”