What is carbon dioxide? 

Carbon dioxide (CO2) is a molecule made up of one carbon atom and two oxygen atoms that is a naturally occurring, colorless, and odorless gas making up approximately 0.04% of the earth’s atmosphere. CO2 is non-flammable and is stable, inert, and non-toxic at atmospheric temperatures and pressures. CO2 is a byproduct of our body’s metabolism (we breath it out from our lungs) and it is essential to plant life on earth. There are both natural CO2 sources (such as plant and animal respiration, decomposition of organic matter, and volcanic eruptions) and man-made sources (such as the burning of coal, oil, and natural gas). 

Carbon dioxide is a greenhouse gas and increasing amounts in the atmosphere can lead to warming of the planet.   

What is carbon capture and storage (CCS)?

CCS is a greenhouse gas mitigation strategy that involves capturing CO2 emissions from point-sources (like industrial facilities) that would otherwise be emitted into the atmosphere and injecting the CO2 into deep underground formations for safe, permanent storage.

Why is CCS important?

CCS is a critical tool to reduce CO2 emissions, especially from industrial sources. Industrial emissions represent ~25% of total U.S. CO2 emissions and have few viable decarbonization options other than CCS. Carbon capture technology is proven, and transportation and underground storage of CO2 has been done for decades.

CCS is a cost-effective, large-scale carbon abatement opportunity, and the emergence of incentives for capturing and permanently storing CO2 makes CCS commercially viable.

Why is the Gulf Coast well situated to be a leader in CCS?

The Gulf Coast is home to some of the country’s largest CO2 emitting industrial facilities. In addition to representing a significant share of the region’s tax base and providing thousands of high paying jobs, these facilities produce materials that are critical to global supply chains in the agricultural, manufacturing, pharmaceutical, construction, transportation, and consumer products sectors. As policies to reduce carbon emissions become more rigorous globally, the industrial sector in Gulf Coast states must adapt to lower the carbon intensity of its products.

Fortunately, the Gulf Coast has vast amounts of underground capacity to safely store CO2. Given the existing infrastructure, abundant and affordable feedstocks, and suitable geology for CCS, the Gulf Coast is competitively advantaged to be a global leader in low-carbon heavy industry.

Is underground injection of CO2 new?

No. Carbon capture and underground injection is a well-understood process that has existed in the U.S. since the 1970s, primarily to support enhanced oil recovery (EOR). Currently, 70 million metric tons per year of CO2 are injected underground for EOR. There are few existing projects that inject CO2 purely for permanent storage, as there was no commercial basis for doing so until recently.

Is CCS safe?

Yes, naturally occurring CO2 has been trapped and stored underground for millions of years within geologic formations. The successful use of EOR shows CO2 can be safely injected and stored underground. Natural gas (methane), liquid petroleum gases (LPGs), crude oil, and other fluids have been safely stored underground in the U.S. for decades.

Is transportation of CO2 safe?

Yes. CO2 pipelines, and other transportation methods, are safe and closely managed under the federal Pipeline and Hazardous Materials Safety Administration (PHMSA), and CO2 pipeline safety data is publicly reported by PHMSA. CO2 is non-flammable and non-toxic, and it does not form explosive mixtures with air as oil and gas do. Because CO2 is transported as a fluid at high pressures, CO2 pipelines are permitted as high-pressure liquids pipelines.

How is underground injection and storage of CO2 regulated?

CO2 storage is heavily regulated by federal and state governments. The Underground Injection Control (UIC) program regulates injection wells used to place fluid underground into porous geologic formations. UIC Program rules promulgated under Safe Drink Water Act (SDWA) revolve around protecting Underground Sources of Drinking Water (USDWs). The UIC program includes well classes for industrial/municipal waste (Class I); oil and gas waste, EOR, and oil and gas salt cavern storage (Class II); mineral solution mining like brine and sulfur (Class III); others (Classes IV and V), and CO2 injection (Class VI). There are over 1,000 existing underground injection wells in the industrial corridor between Baton Rouge and New Orleans.

The U.S. Environmental Protection Agency (EPA) is currently the lead permitting authority for Class VI CO2 injection wells in most states, including Louisiana and Alabama, though the Louisiana Department of Natural Resources (LDNR) has applied to obtain primacy for permitting CO2 injection wells in Louisiana from the EPA.

How does a Class VI permit applicant demonstrate a site is suitable for CO2 sequestration?

An applicant must demonstrate to regulators that the geology is suitable to hold and confine all injected CO2 and displaced formation fluids. The injection reservoirs must have adequate porosity (space to hold CO2) and permeability (ability to transmit injected CO2); the injected CO2 stream must be compatible with formation fluids; and the confining zones (caprock) must be sufficiently thick and cohesive to provide a barrier against upward movement of injected CO2.

An applicant must comprehensively characterize the subsurface area that will contact the injected CO2 or would be subject to elevated pressures. An applicant will collect this information from wireline well logs, geophysical surveys and core samples, among other sources. Structure maps and petrophysical data are inputs to a computational model that projects the maximum extent of the subsurface CO2 plume and elevated formation pressures over the life a project’s injection and post-injection period. That maximum extent is the project’s Area of Review (AoR).

Prior to commencing injection, an applicant must perform corrective action on any existing, inadequately plugged wellbores in the AoR that could become conduits for migration of injected CO2 or displaced formation fluids.

How does the operator of a Class VI well ensure the injected CO2 or elevated formation pressures remain in the AoR?

The Class VI rule requires ongoing testing, monitoring, reporting, and compliance verification during the injection and post-injection period to validate that subsurface CO2 remains in the intended reservoirs. An operator of a Class VI well must continuously monitor injection zones, permeable zones above the confining layers, and USDWs.

The Testing and Monitoring requirements for a Class VI well are significantly more rigorous than other UIC well classes and will provide operators early warning if CO2 or formation fluids are migrating in a manner other than as projected by reservoir models.

How is the government supporting CCS?

Since 2008, the federal government has provided a tax credit for CO2 storage (identified as the “45Q tax credit” for the section of the U.S. Internal Revenue Code that provides for the credit) intended to incentivize the deployment of CCS. In 2022, provisions in the Inflation Reduction Act increased the 45Q tax credit to provide up to $85 per ton of CO2 permanently stored underground (in 2026). To be eligible for a 45Q tax credit, a capture facility must commence substantial construction by January 1st, 2033. The 45Q tax credit is available for up to 12 years.

Additionally, the U.S. Department of Energy (DOE) launched a CCS program in 1997 and performs important research and development around CCS technologies and safety. In 2021, Congress passed the Bipartisan Infrastructure Law which appropriated $12 billion in new carbon management funding over five years, including $2.5 billion to support carbon storage validation and testing through the development of new or expanded large-scale carbon storage projects and associated carbon dioxide transport infrastructure.