Can CO₂ storage sites or pipeline explode?

CO₂ is neither explosive nor flammable.

Is CO₂ hazardous?

Carbon dioxide (CO₂) is an inert gas that occurs both naturally and as a byproduct of industrial processes. It is non-flammable. CO₂ is exhaled when humans breathe out and is emitted into the atmosphere at refineries, manufacturing facilities and power plants. Due to growing environmental regulations and climate mandates, these businesses must reduce their CO₂ emissions. At extremely high concentrations, carbon dioxide temporarily displaces oxygen. However, carbon dioxide dissipates very, very quickly.

What about blow-outs?

A blow-out is a term used to describe when CO₂ quickly surfaces at high pressure. As with all deep oil or gas wells, blow-outs are possible at CO₂ injection sites. Incidents are rare with minimal amounts of CO₂ released that quickly disperse into the atmosphere. Comprehensive precautions are in place to ensure that our team and local emergency personnel are provided with dedicated training and protocol plans to recognize and respond to this scenario.

Can CCS facilities be located near sinkholes or salt domes?

Sinkholes are surface features that occur primarily near salt domes due to salt dissolution on the surface. When planning well locations and injection sites, Tenaska takes into account the geological factors that could cause sinkholes and plans around those areas to ensure safe, lasting facilities.

In fact, proximity to sinkholes and other geologic features will be considered by the U.S. Environmental Protection Agency (EPA) as it reviews the project’s Class VI application. The EPA will not permit a CCS project if it believes it will be substantially impacted by, or impactful to, a relevant salt dome. Salt domes are not viable areas to inject CO₂.

Is CCS regulated?

Yes. CCS storage fields are regulated by the U.S. Environmental Protection Agency (EPA)’s Underground Injection Control Program. This program sets and monitors regulations for injection well siting, construction and operation to ensure drinking water and human health are protected. The U.S. Department of Energy (DOE) also oversees development and technology field testing to ensure that the regulations relating to the safe storage of CO₂ underground are met. Additionally, CCS pipelines must meet requirements laid out by the Pipeline and Hazardous Materials Safety Administration (U.S. Department of Transportation).

How will the storage field be maintained long-term to ensure safe operation?

The facility will have maintenance personnel. The workers will perform line locates, monitoring and maintenance and, if required, emergency response. 

The storage field will have continuous monitoring to alert us to changes in pressure or other anomalies that would indicate a leak. It will also alert us to the upward migration of CO₂ well before it reaches the water table or the surface. If this happens, we will – as required by our permits – stop injecting CO₂. We will then work to identify and repair the leak. In these rare instances, leaks generally are found in the casing near the injection site and are easy to repair.

In the rare instance that CO₂ leaves the storage field, it will travel into other deep formations. The robust design features of the storage field and its deep, deep underground location will prevent CO₂ from reaching the groundwater level or the surface.

Are the pipelines used to transport carbon dioxide safe?

Pipelines continue to be the safest means of transport, with over 5,000 miles of CO₂ pipeline infrastructure in operation across the United States today. There have been only a few instances of leaks on these lines, with the most notable being in Mississippi in 2020. There are a number of design and operational specifications that distinguish our project. The CO₂ that we will transport will be 98% pure. In the well-documented incident in Mississippi, the pipeline also contained hydrogen sulfide in levels harmful to humans that aggravated the impacts of the release.

What additional standards are in place to ensure safety and efficiency?

Our carbon dioxide pipelines will be designed to exceed federal safety requirements and the operating standards of other carbon projects already in operation. The carbon dioxide transported will be required to be a very pure stream of CO₂, coupled with additional purification equipment on- site to ensure we are reaching the threshold of 98% pure product. Another distinguishing design factor is component parts, as we are using a different composition of carbon steel that can better withstand the kinds of external stresses that caused the incident in Mississippi.

How do we know your pipelines won’t rupture?

There are more than 5,000 miles of active CO₂ pipelines in the U.S. today. Modern pipelines are incredibly safe. In most instances of pipeline failure, the fault lies with third-party damages, such as someone digging a deep hole and rupturing the pipeline. This pipeline will have warning tape. In addition, this pipeline will be monitored to detect corrosion. It will have constant monitoring and use real-time data so we can shut down the pipeline immediately if we detect a pressure drop or other anomaly that might indicate a problem. We’ll have the ability to locate where the problem is, dispatch crews to the site, determine the extent of the problem and begin any necessary repairs.