Carbon Capture and Storage: Pros and Cons

Carbon capture and storage (CCS) is part of a portfolio of strategies to combat the climate crisis by lowering the amount of carbon dioxide (CO₂) in the atmosphere. It captures CO₂ emissions from sources like industrial facilities or power plants and transports them to predetermined storage sites, where the emissions are securely stored underground to prevent their release into the atmosphere.

This capturing technique holds great promise in reducing greenhouse gas emissions, though it comes with many notable concerns. Understanding the advantages and disadvantages of carbon capture can help you decide when and where to implement it in your operations.

The Fundamentals of Carbon Capture and Storage

CCS captures emissions before they enter the atmosphere, either through pre-combustion capture, post-combustion capture or oxyfuel combustion, depending on the emission source. The captured CO₂ goes to a long-term storage facility via pipelines or ships. These storage locations are often underground geologic formations.

The goal of CCS technology is to store CO₂ emissions in a space where they cannot enter the atmosphere. Several carbon capture and storage techniques work together to support the overall process:

• Capture: There are various methods of capturing, namely pre-combustion, post-combustion and oxyfuel combustion capture. Pre-combustion captures the CO₂ before the fuel burns, usually by converting the fossil fuel into a mixture of CO₂ and hydrogen. Post-combustion captures the fuel from the exhaust gases using absorbents or chemical solvents after burning. In oxyfuel combustion, fuel burns in pure oxygen instead of air, which leads to an easy-to-capture flue gas stream with high CO₂ concentrations.
• Transportation: The CO₂ moves to a secure storage facility via a designated pipeline, depending on the distance to the storage facility and the volume of CO_2. Smaller quantities can be hauled via ship, rail or truck, although these methods add to carbon emissions and transportation costs.
• Storage: At the storage site, technicians inject the CO₂ deep into geological formations like saline aquifers, basalt formations, deep coal seams or depleted oil and gas reservoirs. Both chemical and physical trapping mechanisms, such as mineralization, dissolution in water, and structural trapping in porous rock formations, work to keep the CO₂ underground.

How Captured Carbon Is Used

While captured CO₂ will often be stored underground, this gas has other uses that can contribute to new industries or more sustainable practices. Some additional uses of CO₂ include:

• Enhanced oil recovery (EOR): Oil recovery helps adapt CCS by using CO₂ to displace residual oil. This improves recovery rates and extends the life span of mature oil fields to displace residual oil.
• Algae cultivation: CO₂ can help to cultivate microalgae, which can be processed into animal feed, biofuels and other high-value products like cosmetics and nutraceuticals. These algae-based systems also offer sustainable alternatives to resource-intensive agricultural practices and fossil fuels.
• Carbonation of minerals: Technicians can mineralize CO₂ to minerals like calcium silicates or magnesium. This technique permanently locks away CO₂ into solid carbonate minerals, with the potential for applications in carbon-negative building materials or soil enhancement.
• Carbon sequestration in agriculture: CO₂ can enhance crop yields and sequester carbon in the soil for other agricultural practices. Afforestation, biochar application and soil carbon enhancement help to promote carbon storage in biomass and soil organic matter, boosting contributions to climate change mitigation.
• Carbon utilization and conversion: Technicians can use biological and chemical processes to convert CO₂ into alternative products. These methods include transforming the gas into methanol, carbon monoxide or formic acid for industrial applications. CO₂ can also be used as plastics or construction feedstock and in synthetic fuels like methane.

The Role of Carbon Capture and Storage in Climate Change Mitigation

CCS is a key technology in a portfolio of climate change mitigation strategies that can significantly contribute to achieving global emission reduction targets. For CCS to have a positive long-term impact, it must be part of a comprehensive strategy that includes renewable energy deployment, energy efficiency improvements and sustainable land-use practices.

CCS contributes to climate change mitigation in the following ways:

• It reduces CO₂ emissions by capturing it before it hits the atmosphere.
• It provides energy security by enabling the continued use of fossil fuels like coal and natural gas in a more environmentally sustainable way. This feature is crucial for energy stability during the global transition to renewable energy sources.
• It can help increase negative emissions when combined with bioenergy from forestry or agricultural biomass.
• It reduces industrial emissions in power generation, cement, chemical and steel production.

The Advantages of Carbon Capture and Storage

The benefits of carbon capture and storage range from climate-related impacts to economic and social considerations. They testify to the efficiency of incorporating this technique into a comprehensive climate mitigation strategy that will yield long-term benefits.

1. Carbon Emissions Reductions

In 2022, the United States alone emitted 6.343 million metric tons of greenhouse gas emissions. Removing CO₂ from the air is challenging, and the concentration technicians can capture is very low. CCS helps to lower carbon emissions by capturing them at the point sources before permanently storing them underground. For example, using the CCS process of oxyfuel combustion makes it easy to remove CO₂ at point sources and obtain a higher concentration of CO₂ at once.

2. Decreases in Social Carbon Costs

CCS can help reduce carbon’s social cost by allowing industries to keep using fossil fuels in a more environmentally sustainable way, especially considering CO₂ has a substantially high social cost. It can lower the economic costs associated with an abrupt transition away from fossil fuels, which is impractical for industries that are heavily reliant on these resources. Additionally, this continued operation helps protect economies and jobs where these industries thrive, mitigating social disruptions to support a smooth transition toward a low-carbon economy.

3. Ability to Remove Other Pollutants Simultaneously

During oxyfuel combustions, using high oxygen concentrations helps significantly reduce the presence of nitrogen oxide and sulfur dioxide in the air. The particulates that oxyfuel combustion creates are easy to remove with an electrostatic precipitator.

4. Benefits to Planetary Health

CCS helps lower greenhouse gas emissions, subsequently limiting rising global sea levels and temperatures, alongside other climate-related impacts. It also helps improve the local air quality where CCS techniques are used, lowering harmful emissions that can contribute to environmental degradation and respiratory diseases.

5. Synergization With the Energy Sector

When CCS combines with bioenergy, this synergy can result in net-negative emissions, strengthening climate change mitigation efforts. It can also complement renewable energy sources by facilitating reliable backup power sources when renewable energy generation fluctuates due to weather conditions. It supports grid stability and energy security, complementing the transition to a cleaner energy mix.

The Challenges of Carbon Capture and Storage

While CCS offers many advantages in global efforts to mitigate the effects of greenhouse gas emissions, implementing these techniques also presents some challenges. Many of these obstacles come down to this technology being used on a limited scale, as there is a lot of room for growth in research and new developments to optimize CCS.

Addressing the potential problems with carbon capture and storage requires stringent regulatory frameworks, ongoing research, technological innovation and stakeholder engagement.

1. High Costs

Equipping existing industries with CCS technologies is costly, especially in the initial implementation stages. Transporting CO₂ to storage sites can also be a substantial effort, which may deter investors and limit the widespread adoption of this technology in regions with limited financial resources. There are also no regulatory drivers in place to incentivize the use of this technology, keeping costs high.

These high costs may be a temporary concern, as research and development efforts, alongside technological advancement, can help make CCS more affordable. When there is more local and international investment in CCS efforts, stakeholders will also have more access to financial incentives for these projects.

2. Counterproductivity When Used for Oil Recovery

Captured CO₂ is often used for enhanced oil recovery, where oil companies inject CO₂ into depleted wells to extract more oil. This method can increase oil production, but it may counteract the goal of reducing greenhouse gas emissions, as it releases some of that CO₂ back into the atmosphere.

While creating more carbon emissions is not sustainable, there is a significant opportunity for carbon offsetting in EOR. CCS-EOR projects often extend the productive lives of oil reservoirs. Collaboration on these projects can also contribute to knowledge sharing and best practices development to benefit oil production and innovative technologies that can create more long-term emission reductions.

3. Potential Safety Hazards in Storage and Transport

Long-term CO₂ storage comes with some risks and uncertainties. There is a potential for leakage, seismic activity and unintended environmental impacts. Sudden leaks at injection sites pose a health risk to animals and people in the area, while gradual leaks from fractures in rock layers can contaminate groundwater and surrounding soil while harming ecosystems.

It is important to note that a CO₂ storage site is monitored before the injection process starts to build a baseline picture of the existing environmental conditions and geology. Site characterization also helps technicians monitor potential changes in different parts of the storage system throughout the injection phase and long afterward to ensure safe carbon storage.

4. Concerns About Effectiveness

There are concerns about CCS’s effectiveness due to inconsistencies from various carbon capture projects. Some projects claim upwards of 95% carbon emission removal, while other studies deliver drastically different data, as low as 10% efficiency. CCS is also energy-intensive and can easily consume up to 50% of a plant’s overall energy output.

Acknowledging CCS challenges like these allows stakeholders to find opportunities to refine the technology used in CCS projects. With more engagement and investment, stakeholders can achieve consistent results while finding innovative ways to lower energy use during CCS extractions.

5. Negative Public Perception

CCS technology may face opposition and negative public perception due to safety concerns and potential environmental risks. There is also a perception that while CCS facilitates the energy transition, it may also prolong the full transition to renewable energy due to complacency with energy security. It is vital to create more public awareness about these methods and increase operational transparency to build trust with CCS projects.

Educating the public about the purpose, safety and benefits of CCS also matters. Advanced monitoring methods, alternatives to underground storage and supporting economic development may demonstrate CCS’s potential while outweighing the concerns.

Why International Cooperation Is Crucial for Carbon Capture and Storage

For climate change strategies to be a success, it is vital to foster international cooperation. Fostering an open dialogue and engaging with local and international stakeholders can help to demonstrate the safety and reliability of CCS technology.

• Knowledge sharing: International cooperation encourages the sharing of technological advancements, best practices and knowledge in CCS. This exchange of information speeds up learning curves, reduces duplication efforts in CCS development and promotes innovation while creating a more positive public perception of CCS technologies.
• Access to funding and resources: Global cooperation provides access to a wider range of international funding sources and private investors, which is vital for implementing large-scale CCS projects.
• Cost reductions: Thanks to shared investments, widespread collaboration on CCS projects can reduce deployment and development overheads. In turn, these savings enable scaling up CCS infrastructures to be more economically viable for investors.
• Addresses transboundary challenges: CCS projects often require cross-border transport and storage, which requires international cooperation to address environmental, legal and technical challenges.
• Global climate goals: CCS helps to realize global climate goals outlined in international agreements, strengthening collective efforts to lower greenhouse gas emissions.
• Capacity building: Global knowledge exchanges can promote capacity-building initiatives, collaborative research projects and training programs. The result fosters technology transfer, develops human capital and builds the local expertise countries need to successfully implement and operate CCS technologies.

Find Your Environmental Solutions With TRC Companies

While CCS is a viable solution to reducing your operations’ greenhouse gas emissions, it comes with noticeable challenges, such as technological limitations, high costs and the potential for leakage. However, while CCS is still growing, your team should begin weighing these aspects to help you make an informed decision about using this technique to promote more sustainable operations.

With over 50 years of industry experience, the experts at TRC are ready to provide you with effective environmental solutions, whether your operations are public or private or you are a government client. Our integrated approach harnesses exceptional environmental, engineering, consultive and applied technology to contribute to your success. Contact us today to optimize your operations while ensuring environmental, health and safety compliance.