advancing the mitigation of Climate Change and Global Warming through Geoengineering education and research

Direct Air Capture

Direct Air Capture (DAC) is a geoengineering or climate engineering approach that extracts carbon dioxide (CO2) from the air or atmosphere and compresses it for long-term storage. The DAC process generally utilizes large fans that blow air across a filter that captures CO2 out of the air.  Once the CO2 is separated from the filter it is compressed into a liquid and generally pumped underground into stable porous rock layers where it is stored for thousands of years.

Carbon Engineering Ltd.’s Direct Air Capture pilot plant in Squamish, British Columbia, Canada. Courtesy of Carbon Engineering Ltd.

A gas pump.
Carbon dioxide removal can mitigate carbon emissions from cars.
A gas station.

Who are the leaders in DAC technology?

Carbon Engineering Ltd., a Canadian company founded by David Keith in 2009 and funded by Bill Gates (see Carbon Engineering Ltd.’s DAC YouTube video below), is a leader in DAC geoengineering technology. Their DAC process, which is currently being scaled up, efficiently captures CO2 that can be stored underground or used in carbon-neutral products such as fuels.

Carbon Engineering Direct Air Capture Technology. Courtesy of Carbon Engineering Ltd.

Carbon dioxide removal technologies can be used at power plants.
A coal plant in Toronto.
A coal power plant.

How does Direct Air Capture work?

Carbon Engineering Ltd.’s DAC process (see figure below) uses powerful fans to blow air across plastic surfaces that support the flow of a CO2 capturing solution, potassium hydroxide. CO2 that is captured and converted into a carbonate salt in the potassium hydroxide solution, is absorbed onto pellets that are heated in a Calcinator in order to produce CO2 gas.

A diagram of Carbon Engineering Ltd.’s DAC process by which they capture and compress atmospheric CO2 for underground storage or use in other storage or low carbon applications. Base image courtesy of Carbon Engineering Ltd.

A coal mine.
A phosphate mine.
A coal terminal.

Similar to Carbon Capture and Storage geoengineering approaches, Direct Air Capture approaches need to be used in conjunction with underground storage or geological sequestration in order to prevent captured CO2 from reentering the atmosphere and contributing to the Greenhouse Effect and Global Warming.

An arctic oil platform.
A oil rig off the coast of Norway.
An oil rig.