On Wednesday of this week, the carbon dioxide concentration in the atmosphere was measured at 415 ppm. The level is the highest in human history and is growing every year.
With all the focus on emissions reduction, the Intergovernmental Panel on Climate Change (IPCC) says it will not be enough to avoid dangerous levels of global warming. The world needs to actively remove historical CO₂ already present in the atmosphere – a process that is often referred to as “negative emissions”.
The CO₂ removal can be done in two ways. The first is to improve carbon storage in natural ecosystems, e.g. B. to plant more forests or to store more carbon in the soil. The second option is to use DAC (Direct Air Capture) technology, in which CO₂ is removed from the ambient air and then either stored underground or converted into products.
The US study published last week indicated that the emergency deployment of a fleet of “CO₂ scrubbers” with DAC technology could slow global warming. However, government and business funding would be required due to the war. So is direct air collection worth the time and money?
Direct CO2 capture from the air is necessary to combat climate change. Shutterstock
What is DAC about?
Direct air collection refers to any mechanical system that absorbs CO₂ from the atmosphere. Plants that are in operation today use a liquid solvent or solid sorbent to separate CO₂ from other gases.
The Swiss company Climeworks operates 15 direct air collecting machines across Europe, including the world’s first commercial DAC system. The company runs on renewable geothermal energy or energy from the incineration of waste.
The machines use a fan to suck air into a “collector” where a selective filter absorbs CO₂. As soon as the filter is full, the collector is closed and the CO & sub2; bound underground.
Canadian company Carbon Engineering uses huge fans to pull air into a tower-like structure. The air flows over a potassium hydroxide solution, which chemically binds to the CO₂ molecules and removes them from the air. The CO & sub2; is then concentrated, purified and compressed.
Captured CO₂ can be injected into the ground to extract oil. In some cases, this can help counteract the emissions that result from burning the oil.
Proponents of Climeworks and Carbon Engineering technology say their projects will be invested and deployed on a massive scale in the years to come. Globally, according to some estimates, the potential market value of DAC technology could reach $ 100 billion by 2030.
Artist’s impression of a DAC system in the US state of Texas. If it were built, it would be the largest of its kind in the world. Carbon engineering
Big challenges ahead of us
Direct air sensing faces many hurdles and challenges before it can really curb climate change.
DAC technology is currently expensive compared to many alternative methods of sensing CO₂, but is likely to become cheaper as technology increases. Economic feasibility is supported by the recent emergence of new carbon markets where negative emissions can be traded.
DAC machines process an enormous volume of air and are therefore very energy-intensive. Research has shown that machines for direct air collection could consume a quarter of the global energy by 2100. However, new DAC methods could reduce the energy consumption of the technology.[Read: How this company leveraged AI to become the Netflix of Finland]
While the challenges of direct air separation are great, the technology uses less land and water than other technologies with negative emissions such as planting forests or storing CO₂ in soils or oceans.
DAC technology is also increasingly being supported by large companies. Microsoft, for example, included the technology in its negative carbon plan last year.
The direct air collection is touted to offset emissions from industry and other countries. Shutterstock
Opportunities for Australia
Australia is uniquely positioned to be the world leader in direct air sensing. It has large areas of land that are unsuitable for growing crops. It has a lot of sunlight, which means that there is great potential for DAC systems to run on solar energy. Australia also has some of the best locations in the world where carbon can be “locked” or stored in underground reservoirs.
Direct air sensing is a relatively new concept in Australia. The Australian company Southern Green Gas and the CSIRO are developing solar-powered DAC technologies. The SGG project that I am involved in includes modular units that may be deployed in large numbers, including near locations where captured CO₂ can be used for oil production or permanently stored.
If DAC technology can overcome its hurdles, the benefits will go beyond tackling climate change. It would create a new manufacturing sector and potentially reinstate workers displaced by the decline in fossil fuels.
Australia has plenty of sunlight and a lot of farmland on which DAC facilities could be built. Shutterstock
The urgency to remove CO₂ from the atmosphere seems to be an enormous challenge. But not acting will bring far greater challenges: more climate and weather extremes, irreversible damage to biodiversity and ecosystems, extinction of species and threats to health, nutrition, water and economic growth.
DAC technology is undoubtedly facing strong headwinds. However, with the right policy incentives and market drivers, there can be a range of measures that reverse climate change.
This article was republished from The Conversation by Deanna D’Alessandro, Professor and ARC Future Fellow, University of Sydney, under a Creative Commons license. Read the original article.
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