The Loan Programs Office (LPO) takes its role in protecting taxpayer interests very seriously, including evaluating the potential impacts of projects in accordance with the National Environmental Policy Act (NEPA).  Given the growth of interest in the carbon capture utilization & sequestration (CCUS) sector, LPO’s Environmental Compliance Division prepared a report in conjunction with the National Energy Technology Laboratory (NETL) as a reference for future applicants, to assist LPO in its review of CO2 injection and storage projects, and to inform the public. The report documents that the CO2 injection and storage process is broadly regarded as a safe endeavor if it is properly managed.

The report provides the current state of the science necessary to complete future environmental reviews of projects involving CO2 injection and storage pursuant to NEPA. In order to identify and assess the potential environmental impacts, the report identifies the potential adverse scenarios, including worst-case scenarios, associated with CO2 injection and storage into underground geologic saline formations that could result in an impact (as defined in NEPA).  The potential scenarios include:

1. Lateral containment failure (fluid movement extends beyond the lateral boundaries of the storage reservoir)
2. Vertical containment failure (fluid movement extends beyond the vertical boundary/barrier)
3. Induced and triggered[1] seismicity resulting from CO2 injection-induced displacement along new or pre-existing faults or fractures. 

Next the report reviewed the environmental impacts associated with the potential scenarios, which include:

1. Contamination of underground sources of drinking water (USDW)
2. Contamination of non-USDW resources (e.g. subsurface, surface, and/or atmospheric resources)
3. Physical damage to surface infrastructure and/or topography.

In accordance with NEPA regulations (40 CFR Part 1502.21), the report evaluated potential impacts that are considered “reasonably foreseeable” even though their probability of occurrence is low.  The report discusses the potential impacts, but concludes that adhering to the Underground Injection Class VI permit process and operational requirements (e.g. site characterization, selection, development, operation, monitoring, and site closure) along with dynamic risk management and facility operation, would avoid or minimize potential impacts at a project site.  In summary, the report finds that if an injection and storage site is properly managed to address the potential scenarios and associated adverse impacts to the human environment, CO2 injection and storage process is broadly regarded as a safe endeavor.

Click here to read the report.

[1] According to McGarr and Simpson [1997], induced earthquakes are commonly understood as events where most of the stress change released during rupture was produced by the human action, while triggered events release a substantial amount of tectonic stress.