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The Secret of Negative Emissions Technology: How Direct Air Carbon Capture Can Save the Planet?
As global climate change intensifies, it is particularly urgent to find effective and sustainable carbon reduction solutions. Among them, direct air carbon capture (DAC) technology has begun to attract more and more attention. The core of this technology is to capture carbon dioxide (CO2) directly from the atmosphere through chemical or physical means and achieve long-term storage. If the extracted CO2 can be safely stored, direct air carbon capture and storage (DACCS) is formed, which is considered a "negative emissions technology" (NET). How this technology works, its environmental impact and future prospects are worthy of further discussion.
How DAC works
Direct air carbon capture technology consists of three main stages: contact stage, capture stage and separation stage. During the contact phase, the DAC system utilizes large fans to move air containing CO2 into the device. Subsequently, in the capture stage, the CO2 is quickly and efficiently combined with the liquid solvent or solid adsorbent. These chemical media are then stripped away by an external energy source (e.g. thermal energy) to obtain a pure CO2 stream and regenerated chemical media.
At present, the operating technology of DAC can be mainly divided into two technologies: low-temperature solid adsorption (S-DAC) and high-temperature liquid adsorption (L-DAC). Both technologies are mature and can be commercialized.
Challenges and potential of DAC
Although DAC technology has great potential, it still faces high cost problems in practical applications. By 2023, the capture cost per ton of CO2 will be more than $1,000, much higher than the existing carbon trading market price. For DAC systems to maintain a net carbon burden, renewable energy must be used, as this process is energy intensive. However, future technological innovations may reduce the energy requirements of this process.
Environmental impact of DAC
Supporters believe that DAC is an important tool to combat climate change and can help achieve the goals of the Paris Agreement. Still, critics warn that overreliance on the technology could delay emissions reduction measures. They pointed out that the resource and energy requirements required by the DAC system are also a burden that cannot be ignored and may even offset the environmental benefits it brings.
According to recent analysis, the DAC system may not be able to capture the expected 3 billion tons of CO2 per year because it requires huge resources and may bring new environmental impacts in the future.
Application of DAC
Practical applications of DAC technology are gradually expanding, including enhanced oil recovery, production of carbon-neutral synthetic fuels and plastics, carbonation of beverages, enhanced concrete strength, and more. These applications require different concentrations of CO2, and obtaining pure CO2 products from the atmosphere requires high energy consumption, which makes the related costs soar.
Global DAC facilities
By 2024, 53 DAC facilities are expected to be operational worldwide, 18 of which are in North America and 24 in Europe. The United States, Canada and some European countries are leading the construction of DAC. China's "CarbonBox" technology is also developing rapidly, aiming to help China achieve carbon neutrality by 2060.
Conclusion
Generally speaking, the future of DAC technology is bright but also difficult. With the further development of technology and the promotion of policy incentives, DAC has the potential to become an important tool in the fight against climate change in the future. However, whether it can achieve the goal of carbon neutrality as scheduled still depends on the efforts and cooperation of countries around the world. Will DAC in the future realize its full potential and become a key technology to solve the climate crisis?
