Geoscience Reference
In-Depth Information
Advantages and Disadvantages
Mineral carbonation is well understood and can be applied at small scales,
but is at an early phase of development as a technique for sequestering large
amounts of captured CO
2
. Large volumes of silicate oxide minerals are
needed, from 1.6 to 3.7 metric tons of silicates per tCO
2
sequestered. Thus, a
large-scale mineral carbonation process needs a large mining operation to
provide the reactant minerals in sufficient quantity.
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Large volumes of solid
material would also be produced, between 2.6 and 4.7 metric tons of materials
per tCO
2
sequestered, or 50%-100% more material to be disposed of by
volume than originally mined. Because mineral carbonation is in the research
and experimental stage, estimating the amount of CO
2
that could be
sequestered by this technique is difficult.
One possible type of geological reservoir for CO
2
storage—major flood
basalts
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such as those on the Columbia River Plateau—is being explored for
its potential to react with CO
2
and form solid carbonates in situ (in place).
Instead of mining, crushing, and milling the reactant minerals, as discussed
above, CO
2
would be injected directly into the basalt formations and would
react with the rock over time and at depth to form solid carbonate minerals.
Large and thick formations of flood basalts occur globally, and many have
characteristics—such as high porosity and permeability—that are favorable to
storing CO
2
. Those characteristics, combined with the tendency of basalt to
react with CO
2
, could result in a large-scale conversion of the gas into stable,
solid minerals that would remain underground for geologic time. The DOE
regional carbon sequestration partnerships are exploring the possibility of
using Columbia River Plateau flood basalts in the Pacific Northwest for
storing CO
2
.
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C
URRENT
I
SSUES AND
F
UTURE
C
HALLENGES
A primary goal of developing and deploying CCS is to allow large
industrial facilities, such as fossil fuel power plants and cement plants, to
operate while reducing their CO
2
emissions by 80%-90%. Such reductions
would presumably reduce the likelihood of continued climate warming from
greenhouse gases by slowing the rise in atmospheric concentrations of CO
2
.
To achieve the overarching goal of reducing the likelihood of continued
climate warming would depend, in part, on how fast and how widely CCS
could be deployed throughout the economy.
