CARBON CAPTURE AND STORAGE: A PROMISING TECHNOLOGY FOR REDUCING CO2 EMISSIONS?

Carbon capture and storage (CCS) is a method to reduce carbon dioxide (CO₂) from big places like power plants or factories and moving it to a place where it won't go into the air, usually underground in rocks.
It can reduce emissions from burning fossil fuels while still using existing fossil fuel power plants and factories. This article will explain how CCS works and discuss its potential benefits and limitations.

The Carbon Capture Process

There are three primary methods used to capture CO₂ from large point sources: post-combustion, pre-combustion, and oxy-fuel combustion.
Post-combustion capture happens once the fuel has been burned. This method usually uses liquid substances called amines to remove CO₂ from the exhaust gases.
Pre-combustion capture involves taking out and capturing CO₂ before the fuel is burned. This is done after the fuel has been turned into a gas or reformed, but before it's combusted with oxygen.
Oxy-fuel combustion uses nearly pure oxygen, not air, to burn fuel. This leads to exhaust gases that are mainly CO₂ and water vapour, which are easier to separate.

Regardless of the capture method used, the end product is high purity CO₂ gas ready for transport and storage. Current commercial capture facilities can remove 80 % to 90 % of emitted CO₂ from flue gases.

Once captured, the pure CO₂ stream is compressed to turn it into a supercritical (thick) fluid that doesn't need as much space to store. It is then transported via pipeline to a suitable storage site. Transporting CO₂ via pipelines is a mature technology already used in other industries like natural gas.
For storage, the CO₂ is injected deep underground, usually between about 900 m and 2,000 m below the Earth's surface. It's stored in spaces within rocks that can be like sponges, such as old oil and gas fields or layers of salty water trapped in the rocks (we call these saline aquifers).
Suitable locations for carbon capture and storage projects are selected based on the presence of a solid, non-porous cap. To ensure the storage remains safe, monitoring wells are installed around the reservoir, allowing specialists to continuously oversee the site's condition.

Energy Penalty in CCS

The implementation of carbon capture and storage (CCS) technology is accompanied by a rise in energy consumption, which is called energy penalty. This extra energy demand comes from the process of capturing and storing carbon dioxide. We have two primary effects:

Incorporating CCS into the operational framework of power generation causes a higher consumption of fuel. As noted by the Intergovernmental Panel on Climate Change (IPCC), the incorporation of CCS technology can lead to a rise in fuel consumption by an estimated 13 % to 44 % for the purpose of electricity generation.

The energy penalty, however, can also result in a decrease in the net power output from power plants for a given amount of fuel. This is attributed to the energy-intensive nature of the CCS process elements, which include the capture, compression, transportation, and secure storage of carbon dioxide emissions.

It should be noted that the energy penalty is an essential factor to consider when evaluating the overall efficiency and economic feasibility of CCS. As of March 2024, the estimated costs for carbon capture and storage (CCS) are between 40 and 120 euros per tonne of CO₂.
At these rates, it is considerably more cost-effective for the industry to continue emitting CO₂ into the atmosphere and offsetting their emissions through ‘CO₂ certificates', which cost about 40 euros per tonne.

CCS for Future Carbon Management

The Intergovernmental Panel on Climate Change (IPCC) states that achieving ambitious climate goals like limiting global warming to 1.5°C will require steep reductions in global CO₂ emissions across all sectors. Fossil fuels are projected to continue meeting the world's growing energy demand for decades to come. This means that technologies like carbon capture and storage (CCS) will be important for transitioning to a low-carbon economy.

By using a variety of strategies together, one sees how carbon capture and storage can act as a temporary support. It helps to make the change-away from fossil fuels smoother until societies can fully rely on cleaner energy sources. Combining different approaches highlights the way CCS can help during this transition period. It allows a more gradual shift from fossil fuels to renewables.

Deployment Progress and Challenges

To date, over 40 large-scale CCS facilities capturing millions of tonnes of CO₂ annually are in operation globally. The majority capture CO₂ from gas and natural gas processing, with several others linked to coal and ethanol plants. Transportation and storage of CO₂ at these sites has proven safe and effective.
But, the main obstacle to using CCS at coal power plants, which are responsible for most of the emissions, is the high capital costs. These costs have made it difficult for widespread adoption of CCS. However, as technology advances, the costs are becoming more competitive and could be further improved with a strong carbon price signal.

Other challenges include developing adequate policy and regulatory frameworks, achieving social acceptance for CO₂ storage, and addressing any long-term liability questions. While scaling up remains difficult, projects under construction suggest the technical and commercial feasibility of CCS is becoming more established.

Modelling the Future Role and Benefits of CCS

Integrated assessment models used by the IPCC and others project CCS has the potential to contribute 10 % to 20 % of the cumulative CO₂ mitigation needed by 2050 to stabilize climate change. This represents approximately 7 to 10 Gigatonnes of CO₂ captured annually globally by mid-century. By reducing emissions from both power generation and heavy industries like steel and cement production, CCS plays an important role in decarbonizing sectors that use hydrocarbon feedstocks as chemical inputs and have fewer alternatives available compared to power generation.

Potential Risks of CCS Operations

The storage process is not without its risks, and it's also necessary to consider the possible downsides. One such risk is the potential for the stored CO₂ to escape from its containment. Should the storage site not be completely secure, there is a chance that the CO₂ could leak into the atmosphere, negating the benefits of the storage and possibly causing harm to local ecosystems.

Another concern is the potential acidification of groundwater. If the stored CO₂ mixes with water, it creates a weak acid. If this sour water seeps into clean water sources, it could harm the drinking water and the health of aquatic life.

Furthermore, some CCS strategies involve offshore storage, where CO₂ is injected into subsea bedrock formations. While this might seem like a viable solution, the monitoring and control of these underwater sites present a considerable challenge.
The lack of direct oversight and the complexities of the marine environment mean there could be unanticipated consequences, such as impacts on marine life or unforeseen interactions with other substances on the ocean floor.

Takeaway

CCS has the potential to be a helpful technology in moving towards a future with less carbon emissions and meeting the world's growing energy needs. While there are challenges to using CCS on a large scale, current projects show that it is technically possible and can reduce emissions. It's important to prioritize increasing its use in the near future where solutions are available in order to achieve long-term climate goals, according to studies that combine different factors.
With more research, demonstrations, and policy support, CCS can serve as a bridge until renewable energy sources can meet more of our energy needs. Overall, the available models suggest that using CCS can be a more cost-effective way to reduce carbon emissions and has lower risks.

But, it's important to take the potential risks seriously and carefully consider them as we use these technologies. The success of CCS depends not only on its ability to reduce CO₂ emissions, but also on how well we manage and minimize any unintended consequences.

While CCS technologies capture carbon emissions at the source, another crucial aspect of our energy future lies in efficiently storing and deploying energy through systems like battery energy storage. At CLOU, our portfolio extends to advanced solutions for electrical energy storage and distribution. Balance load, store excess energy from renewable sources, and guarantee a steady and reliable energy supply are some of the important functions of these systems. As the industry moves towards integrating CCS, the importance of sophisticated energy storage solutions becomes ever more apparent, providing a harmonious complement to emission reduction efforts.
If you have any questions about our metering and energy storage products or how they can support your energy management and sustainability goals, please do not hesitate to reach out.
At CLOU, we are committed to providing solutions that not only measure energy with precision but also contribute to a more resilient and environmentally intended energy landscape.

Thank you for reading. If you'd like to contribute to the controversial discussion with your thoughts and insights, please feel free to leave a comment below. We value your feedback and are always eager to hear from our readers.

Until then, keep shining bright like a solar panel on a sunny day!

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This discussion incorporates material from the Intergovernmental Panel on Climate Change (IPCC) and from the Carbon Capture Journal.