A Canadian company, Carbon Engineering, has published results of a pilot study that shows that CO₂ can be captured from the atmosphere for less than $us100 a tonne – far less than previous estimates of $600 to $1,000 a tonne. The company is commercalising technology which uses the captured CO₂ to produce liquid hydrocarbon fuels.
The CO₂ is captured in a continuous process comprising two loops. The first loop uses an alkaline aqueous potassium hydroxide solution to extract the CO₂ from the air and convert it to a carbonate; the second loop extracts the carbonate ion for making the fuel from the solution and regenerates the alkaline capture fluid.
The company then uses water electrolysis and fuel synthesis techniques to turn the captured CO₂ into liquid hydrocarbon fuels such as petrol, diesel and jet fuel.
Carbon Engineering has been running a pilot plant in British Columbia since 2015 and has been able to achieve costs of less than $us100 a tonne of captured CO₂. The company has been producing fuels from its captured CO₂ since December 2017 and now seeking partners in commercialising the process.