Direct Air Capture (DAC) offers a range of opportunities to create environmental benefits, to produce clean fuels, and potentially to manufacture more sustainable concrete, plastics, and chemicals. At CE, we are focused on two main use cases: permanently storing the captured carbon dioxide (CO2) deep underground to create negative emissions, and utilizing captured atmospheric CO2 to produce clean synthetic transportation fuels.
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, or negative emissions, can be used to counteract emissions that are occurring elsewhere.
Geological carbon dioxide storage, also known as carbon sequestration, has been assessed by leading international bodies such as the Intergovernmental Panel on Climate Change (IPCC). The IPCC and others have 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 sequestration exist in many regions around the globe and collectively have the capacity to store hundreds of years of CO2 emissions underground.
Saline formations are large layers of rocks with porous spaces that are isolated deep underground and contain salt water. The practice of storing CO2 in saline formations has been examined extensively by industry, academics, and government agencies and has been found to present a long-term solution for CO2 storage that has immense capacity. It is being practiced in Norway and Algeria at commercial-scale, and pilot-scale projects have been demonstrated in Japan, Canada, Germany, and the US.
Permanently storing atmospheric CO2 in saline formations allows us to achieve what is known as carbon dioxide removal, or negative emissions. A Direct Air Capture facility built in this way has the sole purpose of removing CO2 from the atmosphere. In the near-term, this will allow us to reduce the net amount of CO2 that is being released into the atmosphere. In the future, once economies have made deep cuts to CO2 emissions, these negative emissions facilities could be used to reduce the overall level of CO2 in the air back to levels deemed safe by climate scientists.
Injecting carbon dioxide into existing oil reservoirs is a common practice that has been performed by the oil and gas industry since the 1970’s. The process, known as enhanced oil recovery, injects CO2 into a depleted oil well to push the last remaining oil deposits to the surface. While historically enhanced oil recovery was not performed to achieve environmental benefits, new laws and regulations – such as California’s Low Carbon Fuel Standard – are now giving guidance and incentive to experienced operators to ensure the CO2 is stored underground permanently during the process.
If done this way, and combined with Direct Air Capture technology, the permanent injection of atmospheric CO2 into the reservoir can partially or completely counteract the emissions from the oil produced. Or, if the quantity of atmospheric CO2 permanently stored is greater than the quantity of oil (i.e. we put more in than comes out), this activity can produce oil and fuels for the transportation sector while also generating net negative emissions. For readers familiar with life-cycle analysis, this means that, depending on factors such as the pattern of the well and the operation of the oil reservoir, DAC with enhanced oil recovery can produce fuels with low, zero, or even negative life-cycle “carbon intensity”.
CE’s AIR TO FUELSTM process starts by using renewable electricity to split hydrogen from water, then combines the hydrogen with captured atmospheric CO2 to produce synthetic crude. This ‘syncrude’ can then be processed into common gasoline, diesel, and jet fuel that works in the engines of existing vehicles without the need to modify them. This technology can form an important complement to electric vehicles by providing a clean renewable fuel for those sectors of transportation that are unlikely to be electrified and that require the high energy density of liquid fuels – long haul transport, marine and air travel.
The AIR TO FUELSTM process produces fuels that are cleaner burning than fossil fuels and can be produced with 100 times less land use than biofuels. Most importantly, our fuels can be produced and used with very low or even zero addition of CO2 to the atmosphere (depending on the energy source used to power the DAC facility). Burning our fuels releases the CO2 that was captured to produce them, but the process would add little or no new carbon emissions to the air because it creates a circular system of emissions in which we continually reuse the atmospheric CO2.