It’s a simple idea: strip CO2 from the air and use it to produce carbon-neutral fuel. But can it work on an industrial scale?
A Canadian company, backed by Bill Gates, says it has reached an important threshold in developing technology that can remove CO2 from the air.
The idea is grandiose yet simple: decarbonise the global economy by extracting global-warming carbon dioxide (CO2) straight from the air, using arrays of giant fans and patented chemical wizardry; and then use the gas to make clean, carbon-neutral synthetic diesel and petrol to drive the world’s ships, planes and trucks.
The AIR TO FUELS™ process involves capturing CO2 from the atmosphere, producing green hydrogen with low-carbon electricity, and reacting the two to form liquid transportation fuels such as gasoline, diesel, or Jet-A. Such fuels can be closed carbon cycle and can displace the need for crude oil.
The hope is that the combination of direct air capture (DAC), water electrolysis and fuels synthesis used to produce liquid hydrocarbon fuels can be made to work at a global scale, for little more than it costs to extract and sell fossil fuel today. This would revolutionise the world’s transport industry, which emits nearly one-third of total climate-changing emissions. It would be the equivalent of mechanising photosynthesis.The individual technologies may not be new, but their combination at an industrial scale would be groundbreaking.
Carbon Engineering has published a peer-reviewed study showing that they can capture carbon for under $100 a tonne.
This would be a major advance on the current price of around $600 per tonne.
The company says their immediate goal is to produce synthetic liquid fuels made from carbon and renewable energy.
Science sceptics
Technological "fixes" to the carbon emissions driving climate change have always been regarded with some suspicion by scientists.
Plans to build solar shields in space or to seed the seas with materials to soak up carbon have been seen as dangerous and a distraction to the more mundane but difficult task of getting people to cut their emissions.
However, plans to capture CO2 directly from the air have been regarded as somewhat more substantial - essentially mirroring the actions of trees.
The idea was first developed by a scientist called Klaus Lackner in the mid 1990s and since then a small number of technology companies have built expensive prototypes of carbon removing devices.
CE’s Direct Air Capture process, showing the major unit operations – air contactor, pellet reactor, slaker, and calciner – which collectively capture, purify, and compress atmospheric CO2
Last year, a Swiss company called Climeworks unveiled a direct air capture installation that extracted carbon and supplied it to a neighbouring greenhouse to fertilise tomatoes and cucumbers.
Now, Canadian firm Carbon Engineering say they have taken a big step forward on cutting the costs of direct air extraction.
CE is privately owned and is funded by private investors, including Bill Gates and Canada oil sands financier Norman Murray Edwards, and with support from governments. CE grew from academic work conducted on carbon management technologies by Professor David Keith’s research groups at the University of Calgary and Carnegie Mellon University, their pilot plant has been running since 2015, capturing about one tonne of CO2 per day.