DIRECTLY CAPTURING CO2 FROM THE ATMOSPHERE

Direct air capture is the process of chemically scrubbing carbon dioxide directly from the ambient air, and then storing it either underground or in long-lived products. This new technology is similar to the carbon capture and storage technology used to capture emissions from sources like power plants and industrial facilities. The difference is that direct air capture removes excess carbon directly from the atmosphere, instead of capturing it at the source. 

It is relatively straightforward to measure and account for the climate benefits of direct air capture, and its potential scale of deployment is enormous. But the technology remains costly and energy-intensive. It is often difficult to pin down costs for new direct air capture technologies, but a 2018 study estimates that it would cost about $94-$232 per metric ton. Earlier estimates were higher. 

Direct air capture also requires substantial heat and power inputs: scrubbing 1 gigaton of carbon dioxide from the air could require nearly 10 percent of today’s total energy consumption. The direct air capture technology would also need to be powered by low- or zero-carbon energy sources to result in net carbon removal.

 Investing in technological development and deployment experience, together with continued progress in the deployment of cheap, clean energy, could advance prospects for direct air capture at a large scale.

Multiple companies have already developed direct air capture systems, despite the near absence of public research and development spending on the technology for many years. In late 2019, however, Congress appropriated $60 million for carbon removal technologies, including at least $35 million for direct air capture, an important step toward the level of investment needed to scale up development efforts. 

The bottom line is that direct air capture is still a new technology and, while it shows enormous potential for scaling up, these systems are the first of their kind and need public support to advance. 

Direct air capture (DAC) is the use of chemical or physical processes to extract CO2 directly from the ambient air. If the extracted CO2 is then sequestered in safe long-term storage, the overall process will achieve carbon dioxide removal. 

A few engineering proposals have been made for DAC, but work in this area is still in its infancy. A private company Global Research Technologies demonstrated a pre-prototype of air capture technology in 2007. A pilot plant owned by Carbon Engineering has operated in British Columbia, Canada since 2015. An economic study of this plant in 2018 estimated the cost at US$94–$232 per tone of atmospheric CO2 removed. Several companies are now working on this approach. 

DAC relying on amine-based absorption demands significant water input. It was estimated, that to capture 3.3 Gigatonnes of CO2 a year would require 300 km3 of water, or 4% of the water used for irrigation. On the other hand, using sodium hydroxide needs far less water, but the substance itself is highly caustic and dangerous. 

DAC also requires much greater energy input in comparison to traditional capture from point sources, like flue gas, due to the low concentration of CO2. The theoretical minimum energy required to extract CO2 from ambient air is about 250 kWh per tonne of CO2, while capture from natural gas and coal power plants requires respectively about 100 and 65 kWh per tonne of CO2. 

➖➖➖➖➖➖➖➖➖➖➖➖➖ 

When you realize that just for the day of Christmas 1000 billion dollars are spent for the sole United States and this figure should be doubled for the whole world, so, I guess we can find the necessary money to filter the air of our planet if we wish so. But do we want it or not that’s another question.

Article by Mr. Patrick Ali Pahlavi