The Crucial Connection: CCUS and Seismic Monitoring
With an escalating environmental crisis, the need for effective mitigation strategies has never been more urgent. Carbon Capture, Utilization, and Storage (CCUS) has emerged as a promising solution capable of significantly reducing the volume of carbon dioxide emissions released into the atmosphere by storing the emissions underground. However, successfully implementing CCUS safely requires highly specialized monitoring techniques; this is where Induced Seismicity Monitoring comes into play.
Seismic Monitoring, traditionally associated with detecting and analyzing earthquake activity, has been repurposed in recent years as a solution for monitoring the subsurface storage of captured carbon. This practice ensures the safety and longevity of carbon storage efforts as time goes on.
In this blog post, we’ll dive into the benefits of CCUS and how seismic monitoring techniques help ensure the safety of the practice.
CCUS: What is it?
CCUS, or Carbon Capture, Utilization, and Storage, refers to the technology that captures carbon dioxide in the air and stores it in geological formations underground. The technology is sometimes referred to as CCS, as while CO2 can be captured and reused (hence the “utilization” piece of CCUS), it is not always. With the increase of greenhouse gas concentrations in recent years and Section 45Q of the U.S. Internal Revenue Code, which provides a tax credit for CO2 storage, the development of CCS projects has continued to boom.
As its name suggests, CCUS often involves three steps: capturing, utilizing, and storing carbon, and it presents an opportunity to bridge the transition from a fossil fuel-dependent society to one with low-carbon fuels. The process aims to mitigate climate change by addressing one of its main culprits– carbon dioxide.
Below, we’ll dive into each step of the process.
Capture: The first step of the CCUS process is capturing carbon dioxide; this typically occurs at the point of emission, such as power plants and industrial facilities that use fossil fuels. Advanced technologies are employed to isolate carbon dioxide from other emissions, “capturing” it before it is released into the atmosphere.
Utilization: Once captured, CO2 can be repurposed in various ways. These uses range from the production of chemicals, fuels, and construction materials to enhanced oil recovery, where it’s injected into oil fields to extract more oil. By finding commercial uses for captured CO2, a harmful waste product is transformed into a commodity.
Storage: However, the volume of CO2 we produce far exceeds what we can utilize commercially. The surplus is dealt with in the final stage of the process: storage. The captured CO2 is injected deep underground into geological formations, such as depleted oil and gas fields or deep saline aquifers. Here, it can be safely stored for thousands or even millions of years, preventing its release into the atmosphere, which contributes to global warming.
While we work to increase renewable energy generation and improve energy efficiency, CCUS provides a solution to manage the existing, and still necessary, fossil fuel emissions. However, effective implementation of this technology is not without its challenges, safety among them. This is where seismic monitoring plays a pivotal role in CCUS serving as an effective solution.
Industries and Regulators
As with anything, the effective application of CCUS and seismic monitoring technologies requires not only the collaboration of various industries but also regulatory oversight; this is where regulatory bodies, including the California Air Resources Board (CARB) and the Environmental Protection Agency (EPA), come into the picture, providing guidance and governance in implementing and managing CCUS projects.
CARB
The California Air Resources Board, or CARB, plays a significant role in setting the standards for environmental policy and regulations across the United States. Their rigorous standards have catalyzed innovative technologies and strategies to combat climate change, including the application of CCUS. CARB develops and enforces regulations for greenhouse gas emission sources, including those involved in CCUS. However, it should be noted that for any CCUS Class VI well operator planning to obtain a CARB permit, continuous downhole seismicity monitoring is a requirement.
The EPA
The Environmental Protection Agency plays a similar role to CARB at the national level– although some U.S. states manage the EPA permitting process through state regulation. Under the Inflation Reduction Act, the organization has established a regulatory framework for the implementation and oversight of CCUS technologies, including guidelines for the safe injection and permanent geologic storage of carbon dioxide, known as the Class VI Underground Injection Control program. The program ensures that Class VI wells, or the sites used to inject carbon dioxide, are protected as resources for underground drinking water. The EPA's regulatory oversight ensures that industries adopting CCUS technologies do so in a way that protects public health and the environment.
In addition to their regulatory roles in the industry, both CARB and the EPA support the continuing research of CCUS and seismic monitoring technologies as well as the sharing of knowledge and safety practices as the technology continues to develop.
CCUS and Seismicity: Understanding Induced Seismicity
When discussing CCUS, it's important to consider seismicity, or the frequency and size of earthquakes that occur in a particular place. However, when CCUS is on the table, we’re not just talking about naturally occurring earthquakes in a particular region. A key concern with CCUS is the potential for induced seismicity, or seismic events triggered by human activities. That’s right: human activities can induce seismic events along fault lines.
During the storage phase of CCUS, carbon is injected deep underground into geological formations, where it can be stored safely for thousands of years. However, transporting carbon underground involves a large-volume injection of CO2 in places where pre-existing faults and fractures exist. Thus, according to the USGS, “if these faults and fractures are large and critically stressed, seismic events can occur with magnitudes large enough to pose a seismic hazard to surface installations and, possibly more critical, the seal integrity of the cap rock.”
To prevent large-scale induced seismic activity, it’s important to keep a close watch on the injection process by monitoring it—this is where Consulting Seismologists can provide their expert knowledge. As minor seismic activity can be detected long before it escalates into a serious event, the data collected from seismic monitors, in addition to CO2 Plume Monitoring, can be used to make adjustments to the injection process, minimizing the potential danger to humans and the environment that induced seismicity might pose.
How Induced Seismic Monitoring Can Help
While there are risks posed by CCUS, the benefits, including the role the technology can play in the fight against climate change, are certainly something to pay attention to. Rather than shying away from the technology because of its potential risks, we can take advantage of what CCUS offer by leaning into systems intended to monitor the potential hazards, such as seismic monitoring.
Examples of Induced Seismicity
Instances of induced seismicity underscore monitoring’s necessity. In 2017, South Korea experienced the country's second strongest earthquake on record, a 5.5 magnitude event later linked to geothermal energy production activities in the area. Similarly, an M4 earthquake in Texas was attributed to hydraulic fracturing (or fracking), highlighting the seismic risks associated with injecting fluids into the Earth.
Success Stories in Seismic Monitoring
On the other hand, the successful implementation of seismic monitoring in CCUS projects shows how it can effectively mitigate such risks. At a carbon capture and storage project in Decatur, Illinois, seismic monitors were installed to detect and analyze any seismic activity associated with the injection of CO2. Despite over one million tons of CO2 being injected into a deep saline reservoir, the monitoring system only detected minor seismic activity, all of which were too small to be felt at the surface.
Similarly, a large-scale CCUS project in North Dakota has seen success with its seismic monitoring program. Throughout the injection process, the seismic monitoring network has provided valuable data, enabling the operators to adjust the injection process as needed to prevent the triggering of significant seismic events.
How ISTI Can Help
With nearly a decade of experience in Seismic Monitoring, our team of seismologists, systems engineers, and data analysts are specialists in designing, implementing, and operating real-time induced seismic monitoring networks. Our infrastructure, networking, and cutting-edge seismic monitoring expertise ensure straightforward, trouble-free service.
Talk to one of our qualified seismologists before submitting your permit application to better understand how to implement a CARB, EPA, or State regulatory body-compliant seismicity monitoring program.