Permanence and Safety of CCS

How is a CO2 storage site monitored?

Monitoring, verification, accounting (MVA), and assessment is an important part of making storage of carbon dioxide (CO2) safe, effective, and permanent in all types of geologic formations. Monitoring occurs before, during, and after the injection phase of a CO2 storage project. The MVA plan for storage projects can have broad scopes, covering CO2 storage conformance and containment, monitoring techniques for internal quality control, and verification and accounting for regulators and monetizing benefits of geologic storage. The location of the injected CO2 plume in underground formations can also be determined, via monitoring, to satisfy operating regulatory requirements to ensure that potable groundwater and ecosystems are protected throughout the project lifecycle.


Monitoring technologies can be deployed for atmospheric, near-surface, and subsurface applications to ensure that injected CO2 remains in the targeted storage formation, as well as to check for indicators of possible CO2 migration out of a storage complexA storage complex consists of: (1) one or more storage reservoirs, with permeability and porosity that allow injection and storage of CO2; and (2) one or more low-permeability seals, which enclose the reservoir(s) and serve as barriers to migration of CO2 out of the reservoir..

Monitoring zones typical to and MVA tools available for a geologic CO2 storage site. [Background image courtesy of Schlumberger.] (click to enlarge)


Setting up soil gas monitoring locations in proximity to a CO2 storage site

There is a large portfolio of technologies available for monitoring of storage projects, many of which are highly developed due to decades of use and experience gained in the oil and gas industry, as well as through advancements through targeted research and development (R&D). Read More!

Through the National Energy Technology Laboratory's (NETL) Advanced Storage R&D area, research has allowed for a portfolio of available monitoring technologies for all types of CO2 storage situations. NETL continues to develop and field test advanced monitoring technologies, as well as supporting protocols, to decrease the cost and uncertainty in measurements needed to satisfy regulations for tracking the fate of subsurface CO2 and quantify any emissions to the atmosphere.

sampling-surface-water-faq.jpg   secarb-faq
Researcher sampling surface water at a DOE-supported CO2 storage site   Various sampling methods being used at the Citronelle CO2 Storage Project (SECARB). Methods include: A. gas-lift; B. electric submersible pump; C. Kuster sampler; and D. U-tube sampler.

Myth: It is impossible to adequately monitor CO2 injection sites.
Reality: Extensive monitoring of CO2 injection sites is already taking place both at the surface and in the subsurface. This is an important regulatory requirement for these projects to operate in the United States.