Direct air capture technology is a critical part of the solution for climate change. The world needs to absorb back massive amounts of CO2 emissions released over the last century and a half, so the planet can start cooling off. Carbon dioxide only makes up a tiny fraction of the atmosphere (around 409.8 parts per million or 0.04%) but it has the ability to trap the Sun’s heat rays and acts like a greenhouse.
Scientists are looking at ways to develop technologies to capture the excess CO2. They are coming up with some cool direct air capture technologies and some of them are still in their prototype stage.
Direct Air Capture Balloons
An Israel – based startup called High Hopes has manufactured balloons that capture CO2 from high altitudes in the air. The balloon is carrying a technology that the CEO explains resembles a fridge – it has a compressor and cooling fluid.
The size of the balloon is roughly the same as two refrigerators. They can fly high in the air where temperatures are around -80 degrees Celsius. At such altitude, the CO2 freezes into snowflakes and gets absorbed by the balloons. Then it is returned back to Earth to be sequestered or reused.
Each balloon can fly between 8 to 10 hours, bring back the CO2 it captures to a ground station for unload, and then return back in the air to capture more. The company’s goal is for each balloon to absorb a ton of CO2 a day. It is expected to cost around $100 to capture a ton but the price could be reduced to $50. That is still much cheaper than other direct air capture technologies.
Another device that sucks CO2 back from the air is the so-called artificial tree. A company called Silicon Kingdom Holdings (SKH) is one of the few direct air capture companies, developing a tree that can potentially capture ~2.5 tonnes of CO2 per year. This technology that resembles the photosynthesis process in trees by taking out CO2 from the air, is 1000 times more efficient than a real tree.
The artificial tree is up to 10 meters high and exposes ~150 sorbent-filled discs, each with a diameter of ~1.5 m. The discs absorb the CO2 within 20 minutes of exposure to ambient air. The Discs release the CO2 at the base of the column, either by heat or humidity.
The device is developed by Dr. Klaus Lackner, a director of the Center for Negative Carbon Emissions and a professor at Arizona State University. Silicon Kingdom Holdings (SKH) announced an agreement back in 2019 with Arizona State University (ASU) to deploy the carbon capture technology.
Artificial trees are not the only cutting-edge technology in capturing CO2 emissions. The city of Turin in Italy has an artificial mountain or sponge mountain that absorbs CO2 from the atmosphere.
It is designed by architect Angelo Renna and uses soil excavated from the construction of the Turin – Lyon high-speed railway. The soil is engineered and mixed with sand and concrete to capture the city’s high air pollution emissions. It is 90 meters high and could also be used simultaneously as a park.
The potential of direct air carbon capture is promising in reversing the concentrations of CO2 in the atmosphere. Investments are going into novel tech that can limit global warming at the rates needed to achieve deep decarbonization.