# Analysis of Technologies for Carbon Dioxide Capture from the Air
## 3 DAC Companies
The captured CO\({}_{2}\) is mixed with water and pumped underground, where, through mineral carbonation, it reacts with basalt rocks. For mineralization, Clineworks partners with the Iceland company Carbfix, an expert on rapid underground mineralization of CO\({}_{2}\). Renewable geothermal energy with a geothermal power plant is used for the regeneration stage of the adsorbent bed. Climeworks has two pilot plants, one in Troia (Italy) and the other in Dresden (Germany) (Climeworks, 2020 [129]). In the first pilot plant, CO\({}_{2}\) is used to produce methane and captures up to 150 tonCO\({}_{2}\)/year [132]. The pilot plant in Dresden is aiming to capture CO\({}_{2}\) to produce carbon-neutral fuels (mainly diesel), exploiting renewable energies for hydrogen production and creating a closed carbon cycle [129]. Overall, Clineworks has 14 pilot plants (with a net removal capacity of 2000 tonCO\({}_{2}\)/year) across Europe, using renewable energy as an energy source and using the captured CO\({}_{2}\) for fuel, food and beverage production. This company aims to remove 225 MtonCO\({}_{2}\) (about 1% of total worldwide emissions) by 2025 [133]. Global Thermostat was founded by [PERSON], a professor from Columbia University in 2010 in New York (USA) [3]. This company has a pilot plant at the Stanford  
Figure 15: The Clineworks plant in Switzerland. Reproduced with permission granted by Clineworks AG [131]. Research Institute (SRI) International in Menlo Park (California) based on the adsorption process, as shown in Figure 16[49]. As with Clineworks, the plant is modular, with a capacity of 1000 tonCO\({}_{2}\)/year [134]. The adsorption system uses an amine-functionalized sorbent of class I: an aminolymer bonded on a porous ceramic honeycomb monolith structure [134]. The regeneration is based on temperature vacuum swing adsorption, using the residual heat from industry and has a desorption temperature of 358-368 K and a desorption pressure of 0.5-0.9 bar [129]. The full cycle has a duration lower than 30 min [129]. The plant produces CO\({}_{2}\) with a purity higher than 98.5% for global food and beverage companies. Global Thermostat has other pilot plants in Magallanes (Chile) and Oklahoma (USA), where the captured CO\({}_{2}\) is used for fuel production. In the future, they want to expand their technology into a facility capturing 1 MtonCO\({}_{2}\)/year, with ExxonMobil as partner [133]. Hydrocell is a Finnish company founded in 1993 [135]. The process used by the company consists of a standard shipping container, fully portable, that is able to capture 1.387 tonCO\({}_{2}\)/year. TVSA is used for regeneration, with a temperature range between 343 K and 353 K (the lowest value among the other systems considered) [129]. Skytree and Infinitree are additional small companies developing DAC technology, with, however, little information available on their operations. Skytree was founded in 2008 in Amsterdam (The Netherlands) as a spin-off of the European Space Agency [136]. The capture process is based on electrostatic absorption and moisturizing desorption at 353-363 K, exploiting low-grade heat [129]. This company's system is characterized by smaller modules compared to the systems of the previously discussed companies, and the captured CO\({}_{2}\) is used for algal growth enhancement in an aquarium. The other small company, Infinitree, was founded in 2014 in Huntington, New York [137]. The capture process is based on moisture swing adsorption using an ion-exchange sorbent, with a capture capacity of 100 tonCO\({}_{2}\)/year. As with Skytree, the CO\({}_{2}\) captured is used to enhance plant growth. Overall, there are 19 plants operating worldwide, capturing 10,000 tonCO\({}_{2}\)/year [40]. However, in order to meet the global goals defined in the international agreements (aiming at the removal of 1000 GtonCO\({}_{2}\) by 2100), it has been estimated that about 13,000 DAC plants with a capture capacity of 1 MtonCO\({}_{2}\)/year are required [138].