Many major scientific assessments have now concluded that the world will need large quantities of carbon dioxide removed from the atmosphere if we are to avoid the worst impacts of climate change. Direct Air Capture with geological storage is one of very few tools that can deliver permanent carbon removal at gigaton-scale.
Geological carbon dioxide storage, also known as carbon sequestration, has been used safely and effectively by industry for decades, with more than 200 million tonnes of CO2 successfully stored in geological sites all over the world. Leading international bodies, such as the Intergovernmental Panel on Climate Change (IPCC), have assessed this practice and concluded that when storage sites are properly regulated, selected, and managed, CO2 can be stored permanently for millions of years with very low risk. Suitable locations for carbon storage exist in many regions around the globe and collectively have the capacity to store hundreds of years of CO2 emissions underground.
Pairing Direct Air Capture with geological storage is a logical, safe, and reliable way to permanently remove vast amounts of CO2 from the atmosphere. Traditional use of fossil fuels extracts carbon from underground geological reservoirs. When used in our cars, homes, or power plants, the carbon is released into the air in the form of CO2, thus driving climate change. Direct Air Capture with secure geological storage can do exactly the reverse. By capturing atmospheric CO2 and permanently storing it underground, this form of carbon removal can be used to counteract emissions that are occurring elsewhere.
The captured CO2 is compressed into a fluid almost as dense as water and injected deep underground to the geological reservoir through a secure and highly engineered well. At the top of the geological formation is a cap rock, an impermeable rock layer that acts as a permanent barrier so the CO2 cannot return to the surface.
Over time, the CO2 will interact with the water and rock within the reservoir, becoming trapped there through the following processes: