Carbon Capture and Storage (CCS) Pros and Cons

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As part of a broad portfolio of tactics against the climate crisis, carbon capture and storage (CCS) has the potential to help reduce the amount of carbon dioxide (CO2) that’s emitted into the Earth’s atmosphere. However, there are multiple barriers that keep CCS from becoming mainstream, such as economic hurdles and potential risks.

What Is CCS?

Carbon capture and storage (CCS) is the process of removing CO2 from industrial processes such as power plants that burn fossil fuels. The CO2 is then transported and placed in long-term storage, typically in underground geologic formations. The CO2 that is removed can either be taken out before combustion occurs or after.

Advantages of CCS

According to the Grantham Institute at the London School of Economics, CCS is currently the only carbon capture technology that can reduce emissions from industrial plants, and it has several advantages over other types of carbon removal technology.

CCS Can Reduce Emissions at the Source

Almost 50% of the greenhouse gas emissions in the United States come directly from energy production or industry. Perhaps the biggest advantage of CCS is its ability to capture CO2 from these point sources and then permanently store it in geological formations. The International Energy Agency estimates that CCS could be responsible for removing as much as 20% of total CO2 emissions from industrial and energy production facilities.

CO2 Is Easier to Remove at Point Sources

One of the major disadvantages of removing CO2 from the air — through technologies like direct air capture — is that the concentration of the gas in the atmosphere is relatively low. In one type of CCS, known as pre-combustion, fuel is treated to form a mixture of hydrogen and carbon monoxide. Known as syngas, the mixture reacts with water to form hydrogen and highly concentrated CO2.

In the CCS process of oxyfuel combustion, oxygen is used to combust the fuel and the leftover exhaust gas also has a very high concentration of CO2. This makes it much easier for the CO2 to react with the sorbent in the CCS process and then be separated. 

Other Pollutants Can Be Removed at the Same Time

During oxyfuel combustion, high concentrations of oxygen used for combustion leads to a significant reduction of nitrogen oxide (NOx) and sulfur dioxide gases. One study conducted for the Argonne National Laboratory showed a 50% decrease in NOx gases in oxyfuel combustion compared with combustion using regular air. Particulates created by oxyfuel combustion CCS can be removed with an electrostatic precipitator. 

CCS Could Reduce the Social Cost of Carbon

The social cost of carbon is a dollar value of the estimated costs and benefits to society from climate change caused by one additional metric ton of CO2 released into the atmosphere in a year. Examples of social costs of additional CO2 emissions could be damage from hurricanes and adverse effects on human health. A benefit might be the increase in overall productivity in the agricultural sector. By removing CO2 directly from the source, net damages to society could be decreased.

Disadvantages of CCS

Even with the advantages of using CCS to help reduce the amount of CO2 that is emitted into the atmosphere, there are several issues related to the implementation of the technology that still need to be worked out.

The Cost of CCS Is High

In order to equip existing industry and electric generation plants with CCS technology, the cost of the product being generated must increase if no subsidies are provided. One report from researchers at the University of Utah cites estimates of a 50% to 90% increase in the cost of electricity in order to pay for the implementation of CCS technology. There are currently no regulatory drivers in most places to incentivize or require the use of CCS, so the cost of equipment and materials to separate CO2, build infrastructure to transport it, and then store it may be prohibitively high. 

Using CCS for Oil Recovery Could Defeat Its Purpose

One current use of the CO2 captured during the CCS process is enhanced oil recovery. In this process, oil companies purchase the captured CO2 and inject it into depleted oil wells in order to free up otherwise unreachable oil. When that oil is eventually burned, it will release more CO2 into the atmosphere. Unless the amount of CO2 captured during CCS also accounts for the CO2 released by the oil that was made available, CCS will simply be contributing to a larger amount of the greenhouse gas in the atmosphere.

Long-Term Storage Capacity for CO2 Is Uncertain

The EPA estimates that not all countries will have enough CO2 storage capacity to properly implement CCS. According to researchers at Khalifa University of Science and Technology, calculating the exact capacities of different storage sites is difficult. This means that the amount of CO2 storage capacity throughout the world is not certain. Scientists at MIT have estimated that the storage capacity for CO2 in the United States is adequate for at least the next 100 years, but uncertainty remains about any time frame beyond that.

CO2 Transport and Storage Sites Could Be Dangerous

While accident rates during the transport of CO2 are relatively low, the potential for a dangerous leak still exists. According to the Intergovernmental Panel on Climate Change, if CO2 were to leak from a pipeline, a concentration between 7% and 10% in the ambient air could pose an immediate threat to human life.

Leakage at the site of underground storage is also a possibility. If a sudden leak of CO2 were to happen at an injection site, it could put the health of surrounding people and animals at risk. A gradual leak from fractures in the rock layers or from injection wells has the potential to contaminate both the soil and groundwater in the area surrounding the storage site. And seismic events triggered by CO2 injection could also disrupt the areas near the storage site.   

Public Perception of Placing CO2 Near Them Is Negative

Storing carbon from CCS has several perceived risks that are not popular among the public. Large-scale implementation of CCS technology will require a place to store the CO2.

According to a study by scientists at the St. Petersburg Mining University in Russia, public awareness of CCS in most of the world is low. However, when people do know about CCS and what it entails, they often have a neutral or positive perception of it, until it comes to the carbon storage location. The negative NIMBY (Not in My Back Yard) effect is often stronger than the public’s positive perception of CCS. People tend to reject large projects like CCS being built near them because of the perceived risks to health and lifestyle, or a feeling that it is not fair that the project is near them and not somewhere else.

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