Can CO₂ sequestration in basalt efficiently reduce greenhouse gas emission?

Area of Science:

• Geology and Earth Science
• Environmental Science
• Waste Management

Background:

• The Columbia River Basalt (CRB) formation in the USA is explored for underground waste disposal, including carbon dioxide (CO2) and nuclear waste.
• Previous nuclear waste projects in the CRB provide a database for developing CO2 sequestration models.

Purpose of the Study:

• To assess the feasibility and capacity of the CRB for high-volume CO2 sequestration.
• To compare the land-use requirements and effectiveness of CO2 sequestration versus nuclear waste disposal.

Main Methods:

• Utilizing data from the Wallula CO2 injection project and prior nuclear waste projects within the CRB.
• Modeling CO2 sequestration capacity based on geomechanical constraints, reservoir permeability, and porosity.
• Estimating the fraction of injected CO2 converted to stable carbonate minerals over a 50-year period.

Main Results:

• CO2 injection rates are geomechanically constrained to 9-19 kg CO2/s, depending on CRB reservoir properties (permeability: 4×10⁻¹⁴-10⁻¹³ m², porosity: 0.1-0.15).
• Over 50 years, 37.1-67.1% of injected CO2 is converted to carbonate minerals.
• CO2 sequestration requires a land area comparable to nuclear waste repositories (0.025% of CRB area for 50 years).

Conclusions:

• The CRB offers a viable geological formation for large-scale CO2 sequestration.
• CO2 sequestration presents a significantly smaller land footprint compared to the energy generated, especially relative to nuclear power.
• Underground geological formations like the CRB are valuable assets for managing atmospheric CO2 emissions.