Forest and mountain landscape

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A new technology, Direct Air Capture (DAC), will remove the carbon dioxide in the atmosphere and reuse it to manufacture a wide variety of products.

“It’s like a vacuum, but smart”

With this image of daily life, scientist Jordi Pedrola described how this new disruptive technology will work and how it will be essential in the coming decades to reduce the amount of carbon dioxide (CO2) in the atmosphere. Direct Air Capture (DAC) technology captures CO2 and filters the air to separate it from other gases.

Working toward net zero emissions by 2050

In the Paris Agreement, nearly 200 countries committed to adopt measures to reach climate neutrality by 2050. This involves further reducing our current emissions of carbon dioxide (CO2), as well as beginning to remove the carbon dioxide already in the air. The International Energy Agency (IEA) estimates that by that date there will need to be capacity to remove eight gigatonnes of CO2 per year in order to achieve this.

The solution to reaching these figures is using so-called negative emissions technologies, which eliminate the CO2 already emitted. The most well-known of these ideas is reforesting burned or barren lands, which will naturally remove more than 50% of the CO2 in the atmosphere with forestation. The other half will be reached by man-made solutions. Today, the most promising is DAC technology.

Reforested woodland

How does this new technology work?

The “smart vacuums” that Repsol Technology Lab CO2 separation technology expert, Jordi Pedrola, mentioned are actually contactors, enormous machines that capture the air, filter it, and separate out the CO2. “Carbon dioxide is found in very low concentrations in the atmosphere, barely 400 parts per million, and DACs are able to capture that vanishingly small portion. Then, the substances and methods used, like liquid sorbents and solids, are selective enough to separate CO2 from other gases such as oxygen and nitrogen,” he explained.

Today, the major challenge to implementing this technology is reducing its energy and financial costs. “The level of energy required is about 2,000 kWh per tonne of CO2,” said Mariano Marzo, senior fellow emeritus at the University of Barcelona and director of the CO2 Capture and Storage Fellowship there. Alternatively, scientists are developing new electrochemical separation technologies that “do not require energy in the form of heat to separate CO2, but rather only energy in the form of electricity.” This makes energy demand “much lower, around 700 kWh per tonne.”

Reusing CO2 in different sectors

Synthetic fuels, methanol, concrete, and polymers to produce foam for mattresses are some of the applications for CO2 removed from the atmosphere.

Once separated and processed, CO2 can be used as a raw material in a variety of processes. For instance, it has been used in small scale to produce urea, a chemical compound used to make fertilizers. It is also used to carbonate soft drinks, preserve food, treat water to balance the pH, in cooling systems, and more.

Thanks to the transformation of CO2, the future holds a myriad of practical uses yet to be fully explored, including the manufacture of synthetic ethanol for the chemicals industry, new types of concrete, and various polymers to produce the foams used in mattresses. The most notable use is for manufacturing synthetic fuels, including the ones that Repsol will produce at its upcoming plant in Bilbao. Also known as e-fuels, these fuels are produced with CO2 and renewable hydrogen, emit net zero emissions, and will be able to be used in the combustion engines of all vehicle types.

CO2

Countries on the cutting-edge of DAC technology

Although it has been researched since 1999, the implementation and effective expansion of DAC technology seemed more like a dream than a reality only five years ago. Today, however, there are 19 plants in Europe, the United States, and Canada with capacity to capture 10,000 tonnes of CO2 per year. But this technology is still in its infancy. According to IEA forecasts, with the new facilities slated for development, 85 million tonnes of CO2 could be separated by 2030 and one gigatonne by 2050.

The operating facility with the most CO2 absorption capacity is called Orca. It can remove 4,000 tonnes per year; it is located in Iceland and was created by the Swiss company Climeworks. But its short-term ambition is to multiply this capacity. An enormous DAC system is currently being built in Texas by the Canadian company Carbon Engineering, which expects to capture one million tonnes per year by 2024.

Benefits and advantages

It seems clear that in order to eliminate the CO2 in the atmosphere, we need to combine different solutions, like reforestation and DAC technology. And although they complement one another, it is true that artificial CO2 capture does have certain advantages.

“One of the major benefits of Direct Air Capture is the amount of space it takes up, 150 times less than reforestation,” Mariano Marzo explained. For instance, to remove one gigatonne of CO2 you would need a surface area equivalent to one third of the Community of Madrid. To capture one gigatonne naturally, on the other hand, you would need to reforest 800,000 kilometers, more than 1.5 times the surface area of Spain. It also offers another advantage in terms of space, as “plants can be built near places where the captured CO2 will be used or applied,” while ensuing transportation cost savings.

DAC technology proves that human effort is able to provide complex and imaginative technological solutions to the problems facing our present and threatening the future of the planet. Today, these new technologies are one of the major sources of hope in the fight against climate change.

 

Published in La Vanguardia