Explore the technologies used to capture CO2 from industrial processes and Earth's atmosphere, looking at its impact, methods and challenges.

As the world grapples with global warming, measures should be considered if we want to achieve the ambitions of the Paris Agreement and limit future temperature increases to 1.5°C (2.7 °F). But increasing efforts and taking measures to reduce greenhouse gas emissions will not be enough: we also should deploy technologies to remove carbon from the atmosphere.

On this page we explore carbon capture technology, which plays a crucial role in reducing emissions from power and industrial plants. This technology encompasses various methods such as absorption, chemical looping combustion and others, offering significant benefits in terms of environmental impact, economic viability and public acceptance.

What is carbon capture and why is it important?

Carbon capture, utilisation, and storage (CCUS) comprises a suite of technologies designed to mitigate climate change by capturing carbon dioxide (CO₂) emissions from various industrial processes and power generation, including existing power plants.

The captured CO₂ can be either stored underground in geological formations such as saline aquifers or utilised for example in liquid fuel production, or the manufacturing of consumer goods, such as plastics or cosmetic ingredients. Carbon dioxide removal (CDR) technologies, like bioenergy with carbon capture and storage (BECCS) and direct air carbon capture and storage (DACCS), are crucial in achieving net zero emissions globally by removing existing CO₂ from the atmosphere.

What is the impact of carbon capture today?

Around 230 Mt (507063 lb.) of CO₂ are currently used each year, mainly in direct use pathways in the fertilizer industry for urea manufacturing (~130 Mt; 286601 lb.) and for enhanced oil recovery (~80 Mt; 176370 lb.). New utilisation pathways in the production of CO₂-based synthetic fuels, chemicals and building aggregates are gaining momentum. The current project pipeline shows that around 10 Mt (22046.2 lb.) of CO₂ per year could be captured for these new uses by 2030, including around 7 Mt (15432.4 lb.) CO₂ in synthetic fuel production.

Capturing carbon dioxide is most cost-effective at point sources, such as large fossil fuel-based power stations and industries that account for major CO₂ emissions (e.g., cement or steel production, natural gas processing, synthetic fuel plants and fossil fuel-based hydrogen production plants). Extracting CO₂ from air is possible, but since the concentration of carbon dioxide in the atmosphere is significantly lower compared to CO₂ coming from traditional flue gas, the process is energy- and therefore cost-intensive.

Around 40 commercial facilities are already in operation applying CCUS to industrial processes, fuel transformation and power generation. The capacity amounts to more than 45 Mt (99208 lb.) per annum. CCUS deployment has trailed behind expectations in the past, but momentum has grown substantially in recent years, with more than 500 projects in various stages of development across the CCUS value chain.

But global CCUS capacity needs to grow more than 100 times in the longer term, reaching 4 to 6 gigatons CO₂ by 2050 and decarbonising around 15 to 20 percent of today’s energy-related emissions to meet current net-zero targets.

What are the safety, efficiency and cost implications of carbon capture?

Ensuring a safe carbon capture process is critical

There are several safety considerations throughout the carbon capture process. Measures to prevent leakage should be taken and carefully executed as leakage could have severe environmental and health implications. During capture, handling and transport, exposure to CO₂ can be hazardous – breathing oxygen depleted air entails health risks and severe troubles such as drowsiness or increased cardiac output. Therefore, proper safety protocols are essential to ensure personnel safety. Selecting and maintaining a storage site for CO2 involves careful consideration of regulatory, safety and environmental impacts, highlighting the importance of addressing these aspects to mitigate potential environmental and social concerns.

Once captured, the CO₂ is compressed and transported via pipelines, road transport or ships to either further processing or to suitable storage sites. Ensuring that the stored CO₂ remains securely underground is crucial. When it comes to transportation, pipelines, ships and trucks used for CO₂ transportation must be designed, operated and monitored in a suitable manner to prevent accidents.

Impurities in CO2 streams, like sulfur and water, could lead to increased corrosion that potentially compromises pipeline integrity in the long run along with negative effects on compressors, valves and metering systems. For this reason, it is crucial to ensure a high level of purity. Furthermore, there is a risk of phase changes. If transported in dense or supercritical phase, the CO2 has a density similar to that of a liquid, but a viscosity closer to that of a gas. This makes the reliable flow measurement – a prerequisite for custody transfer – a challenging task.

Capturing CO₂ consumes high amounts of energy. The efficiency of power plants or industrial processes decreases due to the additional process steps and the resulting energy consumption involved.

Cost and economic viability of carbon capture

Building and operating carbon capture facilities requires significant investment, while the energy consumption during capture and transport adds to operational expenses. Additionally, the efficient, continuous monitoring of operations and the maintenance of storage sites to ensure long-term liability contribute to ongoing costs. Looking at carbon capture, the cost can vary greatly by CO2 source, from a range of USD 15-25/t CO2 for industrial processes producing “pure” or highly concentrated CO2 streams (such as ethanol production or natural gas processing) to USD 40-120/t CO2 for processes with “dilute” gas streams, such as cement production and power generation. Capturing CO2 directly from the air is currently the most expensive approach, ranging from USD 250 to 600/t CO2. The cost-effectiveness of carbon capture technologies depends on factors like CO₂ price, policy incentives and technological advancements. Governments can incentivise carbon capture through subsidies, tax breaks and emissions reduction targets, while international collaboration is crucial for knowledge sharing and standardisation. A primary example is the Inflation Reduction Act (IRA) of 2022, combining the objectives of reducing domestic inflation – notably brought by the global energy crisis – while tackling climate change. A key stated goal of the act is to reduce carbon emissions by around 40 percent by 2030.

Implementing carbon pricing mechanisms can influence carbon capture adoption, but public perception also plays a role: Public acceptance, regulatory frameworks and social awareness will have positive impact on the future expansion and large-scale deployment of carbon capture technologies. While carbon capture offers a promising pathway to reduce emissions, a delicate balance between safety, efficiency and cost considerations is required. Continued research, innovation and supportive policies are essential for successful implementation – and reaching net zero goals.

Article source:

https://www.de.endress.com/en/sustainability-solutions/what-can-we-do-with-co2/how-does-carbon-capture-work#anchor8 

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