One hot summer day two years ago, Kathy Stockdale checked her mailbox and found a slip of paper that would change her life. The humble notice revealed that two carbon capture companies wanted to seize part of her family’s farmland in Hardin County, Iowa, for a pair of pipelines slated to pass through it. But Stockdale wasn’t going to give up her property without a fight.

Pipelines are hardly new to the Midwest; thousands of miles of natural gas conduits already crisscross the region. But fresh tension surrounds the construction of a relatively new kind of conduit called a carbon capture pipeline, and the Stockdales’ land lies in the potential pathway of two of them. These pipelines are part of an effort to reduce greenhouse gas emissions from ethanol production plants by capturing and storing carbon dioxide that would otherwise be released into the atmosphere. But despite the green intentions behind the technology, environmentalists are actually joining landowners in pushing back against it. Many experts worry the pipelines could spring deadly leaks or contaminate water—and they question how effective such projects will actually be at fighting climate change.

Stockdale and her husband, Raymond, who have lived on their farm for 47 years, were stunned when representatives from a carbon capture company suddenly showed up just three months after the couple received the notice. Without asking permission, the reps began planting stakes where the pipe would go, Stockdale says. “I have never felt more disrespect in my life,” she adds. She decided to fight back against the use of eminent domain—a legal concept that allows companies to seize private property for public use through the local, state or federal government (although the landowner must be fairly compensated). Stockdale has been fervently attending public hearings on permits, researching pipeline safety and talking with legislators. She has had a lot of sleepless nights. And even though she says she isn’t interested in environmental protection, she has partnered with the local Sierra Club chapter for support.


ADVERTISEMENT
Environmentalists might not seem like a natural ally in a battle against green technology, but they have concerns about the growing U.S. web of carbon capture pipelines—which currently includes more than 5,300 miles of conduit. And carbon capture technology continues to gain traction nationwide; the Biden administration recently announced that it would spend up to $1.2 billion on carbon capture and storage projects, signaling a commitment to this technology as a means to achieve net zero emissions.

Here’s how the carbon capture process works: It begins at an industrial site, such as an ethanol or power plant, that produces a lot of carbon dioxide emissions. As the plant burns fossil fuels, a liquid solvent absorbs the exhaust and separates its gases. A storage chamber collects separated carbon dioxide (which would otherwise enter the atmosphere and trap heat), and harmless nitrogen and oxygen are released. Next, the system liquifies the CO2, which flows through steel pipelines to a designated storage site. Once it arrives, another pipe injects it deep underground, where it is isolated from the atmosphere and will no longer actively contribute to climate change.

But the process comes with risks.

CO2 remains a liquid in the high-pressure, high-temperature environment inside a pipeline. But if the pipeline ruptures, that liquid escapes as a colorless, odorless gas that is difficult for people to detect without specialized instruments. This CO2 can displace oxygen and potentially cause suffocation, drowsiness and sometimes death; in fact, the gas is sometimes pumped into specialized chambers to euthanize livestock on farms. In 2020 heavy rains triggered a landslide that damaged a carbon capture pipeline in Satartia, Miss. The pipe burst and released CO2, suffocating 45 people so severely that they needed to be hospitalized.

Fortunately, these pipelines have a low probability of failure. Leaks are few and far between. But Bill Caram, executive director of Pipeline Safety Trust, says that any one rupture can have unacceptable consequences. “We have a goal of zero incidents. And I think that’s a shared goal among regulators and the industry,” Caram says. “We’re a long way away from that happening.”


ADVERTISEMENT
A study released in May found that carbon capture pipelines are more likely to experience small punctures than large ruptures such as the one in Satartia. Smaller holes release the gas at a slower rate, which makes them harder to locate. And a delayed response to smaller punctures could cause them to be deadly.

When CO2 vaporizes and escapes, it causes the temperature in the pipeline to drop immediately—a process Caram describes as “violent.” The escaped gas doesn’t ignite or dissipate. It moves quickly along the ground and can collect in low-lying areas, including small valleys and basements near the pipeline route. If a person in one of these pockets breathes air with a 10 percent concentration of CO2, they can fall unconscious within one minute.

Additionally, impurities in the liquified gas can erode a pipeline and increase the chance of a leak. Potentially dangerous contaminants include water, nitrogen oxides and sulfur oxides—all of which are sometimes found in CO2 captured from power plants. There is only limited research on how these contaminants will affect the gas’s stability in storage. Experts note that relatively large concentrations of oxygen could potentially dissolve caprock, a natural geological formation that traps oil and coal—and injected CO2—and keeps them from escaping to the surface. One of the main problems, Caram says, is that there are no federal regulations from the Pipeline and Hazardous Materials Safety Administration about limiting impurities, even after the 2020 Satartia incident. “Operators can clean it up somewhat. They can dry it out and get the water out of there to a certain extent,” Caram says. “But there’s no regulation saying that the pipeline can’t have these impurities in it. It’s just kind of up to operators to do it.”

newsletter promo
Sign up for Scientific American’s free newsletters.

Sign Up
Beyond their safety concerns, experts question whether carbon capture and storage is even an effective strategy for reducing greenhouse gases. Noah Planavsky, an isotope geochemist at Yale University’s Center for Natural Carbon Capture, says the practice would certainly reduce the CO2 in the air—but the overall situation is not that simple. “It’s not whether or not it’ll remove carbon. It will remove carbon,” Planavsky says. “But are we doing things that are actually propagating further use of fossil fuels?”

Investing massive amounts of money in carbon capture and storage, and the pipelines that come with it, will lower carbon dioxide levels in the atmosphere. But with limited federal money allocated for long-term climate change mitigation, Planavsky is not sure this technology is the best use of those funds. He says it’s important to consider whether carbon capture will be used as an excuse for not phasing out fossil fuels.