How does carbon capture and storage work?

Carbon dioxide (CO2) is a natural and essential compound in the Earth’s atmosphere. However, the current concentration of 422 ppm (parts per million) represents a 50% increase over pre-Industrial Revolution levels.

Since then, human activities, especially the burning of fossil fuels, have driven the increase of this gas to dangerous levels, with few significant actions to mitigate these emissions. As carbon dioxide and other greenhouse gases accumulate in the atmosphere, they act as a barrier, trapping solar heat that should be released back into space at night, resulting in the phenomenon of global warming.

Current carbon capture and storage (CCS) technologies have proven to be very efficient and are currently part of global agendas, seen as one of the possible solutions to reduce the impacts of climate change.

As a contemporary environmental problem closely linked to a lifestyle that generates exorbitant carbon burning, let's better understand the role of this activity and alternative and technological ways to reduce this impact with a view to building a more sustainable future. Stay with us!

After all, what is carbon capture and storage?

The most widely used technique currently related to CCS – Carbon Capture and Storage, is based on capturing carbon dioxide for storage underground, in pre-established locations or for reuse in the company's own industrial processes. In this case, the acronym CCS changes to CCUS – Carbon Capture Utilization and Storage, which means capturing, storing and using carbon.

Petrobras is a great example of this “recycling”, reinjecting carbon into nine oil platforms as a way of maintaining internal pressure in the reservoir and increasing the amount of oil extracted.

By capturing this element, it is possible to generate bioenergy, and the application of CCS can lead to the removal of carbon from the atmosphere. This technique, therefore, is a great capture opportunity, as 40 million tons applied to these processes called BECCS, an acronym for Bioenergy Energy with Carbon Capture and Storage, combine the application of CCS with bioenergy.

Carbon capture

The process consists of separating CO2 from other gases generated by the burning of fossil fuels, such as coal and natural gas, or in industries such as steel mills, refineries, and cement and fertilizer plants. Carbon dioxide can also be removed before combustion, but this technique is only available in facilities that have more robust technologies.

After capture, the gas of interest is compressed into a liquid state and transported to suitable storage sites, usually underground, such as old oil and gas reservoirs, deactivated coal mines, and porous rock formations with salt water.

In addition, CO2 can be removed directly from the atmosphere through filters and chemicals, in a process known as direct air capture (DACCS). However, these technologies have high energy demands and consequently high operating costs.

CCS can enable regional competitiveness and market development

The implementation of CCS projects has stood out as a promising solution, with the potential to address several SDGs. In addition to contributing directly to SDG 13 - Climate Action, CCS can also have positive impacts on the generation of affordable and clean energy (SDG 7), the creation of decent work and economic growth (SDG 9), industry, innovation and infrastructure (SDG 9), life below water (SDG 14) and on land (SDG 15), and the implementation of Partnerships (SDG 17).

When applied to thermal power plants, CCS projects contribute to SDG 7, promoting the decarbonization of energy production from fossil fuels, which are generally more accessible and account for over 80% of the global energy matrix. This means that CCS can, in many cases, enable the production of affordable and clean energy.

In addition to being a new economic activity, with expertise and its own value chain, which will generate jobs and contribute to the local economy, the adoption of carbon capture and/or storage structures within existing industrial processes will help many industries continue to operate competitively in a context of pressure to reduce emitting activities.

In this way, CCS projects can also be important vectors for regional development, as they encompass the creation of a new economic stream and an entire supply chain focused on CO2 storage operations, and continue to maintain existing jobs.

CCS projects rely on innovative technologies that can contribute to improving industrial infrastructure and promoting innovation in different sectors of the economy. The implementation of CCS can help drive the transformation of industry towards a low-carbon economy and promote the adoption of cleaner and more efficient technologies.

What are the advantages and disadvantages of carbon capture?

There are pros and cons when it comes to carbon capture and storage technology. The first setback is that, until this tool is effectively developed and disseminated, a lot of fossil fuel will still be burned. This makes many scientists question the validity of this solution. After all, the very existence of CCS can reinforce the increase in the use of these fuels.

On the other hand, those in favor of CCS argue that the use of fossil fuels is far from over. According to John Thompson, a participant in the Fossil Fuel Transition Project, the use of these energy sources continues to increase. Therefore, a technology that reduces atmospheric CO2 emissions is necessary and needs to be implemented, even if it is not yet the best solution.

Another cost, in addition to energy, is the high investments required. To contain global warming to the 1.5° C target, more than one hundred CCS projects would be needed. In order to eliminate 270 million tons of carbon dioxide pollution per year, according to the International Energy Agency (IEA).

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About the author:

Everton Oliveira is the Director of the Sustainable Water Institute and founder of Hidroplan, a respected environmental consultancy with over 33 years of experience, in addition to having worked as a professor at USP and UNESP.