Direct Air Capture (DAC) is a technology that captures CO2 from atmospheric air and purifies it for use or storage. This captured, compressed CO2 can then be used to create products, like clean-burning liquid fuels. As of June 2020, there were 15 direct air capture plants operating worldwide, capable of capturing 9,000 tCo2/year.
There are two main technologies used to capture CO2 from the air. These are a liquid systems and a solid system. The liquid system passes air through a chemical solution which removes the CO2 while returning the rest of the air to the environment. And the solid system uses solid sorbent filters that chemically bind with CO2. When heated, the filters release the concentrated CO2 which can be captured from storage or use.
In 2020, the cost of direct air capture, especially compared to carbon capture of flue gas from a power station or cement plant, is more expensive and requires more energy for operation. The type of technology varies the price, but the need to compress the CO2 in order to be captured and stored creates a further step which at-source carbon capture technologies do not require.