Vacuuming your house to be rid of dust can be quite a chore. Dirt and dust seem to accumulate faster than you can keep up. Yet, ever since the first vacuum was invented in 1908, larger and more powerful vacuums have made cleaning household carpets and factory floors far easier. With greenhouse gases building up faster than trees and technology can clean up, a new sort of vacuum seems needed. Amazingly, innovation has delivered one.
Sometimes the size of whole factories, these ‘vacuums’ can remove carbon dioxide straight from the atmosphere in what is becoming a growing business. While not actual vacuums powered by suction, Direct Air Capture (DAC) facilities utilize massive filters and a series of chemical reactions to remove, compress, and reuse carbon dioxide for other commercial products or store the CO2 underground. Not only does DAC help remove CO2 from the atmosphere, but a variety of methods and new technologies have made DAC a much more flexible solution to combatting climate change.
Direct air capture can be facilitated through active and passive means. The air capture company Climework’s DAC system uses a fan to direct air through a series of filters that pull carbon dioxide from the air. Once the filter has been fully saturated with CO2, the filtration system closes and the carbon dioxide is heated to over 100 degrees Celsius, mixed with water, and pumped into the Earth for storage.
A passive method that does not require energy-intensive filtration systems is the MechanicalTree, developed by Arizona State University’s Center for Negative Carbon Emissions and Dublin-based Carbon Collect Inc. These 10-meter-tall structures contain tiles that absorb carbon dioxide constantly as air passes through them and lowers into containers that suck the CO2 into storage when filters become fully saturated. These ‘trees’ require no energy to operate and can remove one metric ton of CO2 per day. MechanicalTrees are easily scalable and do not need to be placed near an emissions source to extract carbon dioxide.
Unlike dust in a vacuum that is simply discarded, DAC technology can actually add value by repurposing the sequestered carbon. Captured carbon can be used in products as wide-ranging as carbonated drinks, as a supplement for speeding up vegetable growth in farms, and even used in the oil and gas extraction process.
The compressed CO2 that is produced from direct air capture is used frequently in fossil fuel industry processes. Enhanced Oil Recovery (EOR) uses CO2 to pressurize oil reservoirs in order to extract the last remnants of oil still in the ground. Using CO2 for this process also locks it underground, completing the final step of the carbon capture and storage process. A DAC plant being built in Texas in a partnership between Occidental Petroleum and Carbon Engineering will use 50 million tons of CO2 for EOR annually.
Greener options include using CO2 for agriculture and fertilizers, infused into concrete and other building materials, converting it into feed for fish and other animals. Climeworks’ smaller-scale DAC facilities have routed 900 tons of carbon dioxide to farms growing a range of crops that will help enhance their growth. Finally, Coca-Cola has begun to purchase Climeworks’ carbon dioxide for use in carbonated beverages as a way for the company to reduce their carbon footprints. The harnessing of captured carbon for sale to other industries is what has led to an uptick in investments backing DAC in recent years, but challenges remain.
Despite multiple industries finding uses for captured carbon, several barriers remain for DAC to become a more widely used technology. Simply removing CO2 from the atmosphere for storage underground has advantages. Carbon capture must therefore be able to effectively market its compressed CO2 to more industries. While the cost of capturing a ton of CO2 has fallen from $600 in 2011 to between $94 and $232 today, the need for large amounts of energy to power carbon capture facilities hampers the carbon neutrality of the carbon capture facilities themselves. Innovative ways to integrate captured carbon dioxide into other industrial processes like concrete production will only broaden its uses.
Companies like Microsoft and Audi have already poured millions into Climeworks DAC design and given more time, DAC can be another tool in the battle against climate change. As other climate-friendly technologies like renewable energies and carbon offsets become more commonplace in reducing carbon footprints, direct air capture will provide an economical solution to emissions in the next decade.
Investors and policymakers can help push direct air capture into economic relevance by continuing to encourage captured CO2 to be further utilized in manufacturing processes. Direct air capture can become a valuable tool in the fight against climate change and can be paired alongside other innovative technologies to minimize emissions and eventually turn whole industries carbon negative.
Written by Roy Mathews, Public Policy Associate
The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.