A technology that removes carbon dioxide from the air has received significant backing from major fossil fuel companies.British Columbia-based Carbon Engineering has shown that it can extract CO2 in a cost-effective way.It has now been boosted by $68m in new investment from Chevron, Occidental and coal giant BHP.
The quest for technology for carbon dioxide removal (CDR) from the air received significant scientific endorsement last year with the publication of the IPCC report on keeping the rise in global temperatures to 1.5C this century.
In their “summary for policymakers”, the scientists stated that: “All pathways that limit global warming to 1.5C with limited or no overshoot project the use of CDR …over the 21st century.”
Around the world, a number of companies are racing to develop the technology that can draw down carbon. Swiss company Climeworks is already capturing CO2 and using it to boost vegetable production.
Carbon Engineering says that its direct air capture (DAC) process is now able to capture the gas for under $100 a tonne.
With its new funding, the company plans to build its first commercial facilities. These industrial-scale DAC plants could capture up to one million tonnes of CO2 from the air each year.
So how does this system work?
CO2 is a powerful warming gas but there’s not a lot of it in the atmosphere – for every million molecules of air, there are 410 of CO2.
While the CO2 is helping to drive temperatures up around the world, the comparatively low concentrations make it difficult to design efficient machines to remove the gas.
Carbon Engineering’s process is all about sucking in air and exposing it to a chemical solution that concentrates the CO2. Further refinements mean the gas can be purified into a form that can be stored or utilised as a liquid fuel.
The captured CO2 is mixed with hydrogen that’s made from water and green electricity. It’s then passed over a catalyst at 900C to form carbon monoxide. Adding in more hydrogen to the carbon monoxide turns it into what’s called synthesis gas.
Finally a Fischer-Tropsch process turns this gas into a synthetic crude oil. Carbon Engineering says the liquid can be used in a variety of engines without modification.
“The fuel that we make has no sulphur in it, it has these nice linear chains which means it burns cleaner than traditional fuel,” said Dr McCahill.
“It’s nice and clear and ready to be used in a truck, car or jet.”
CO2 can also be used to flush out the last remaining deposits of oil in wells that are past their prime. The oil industry in the US has been using the gas in this way for decades.
It’s estimated that using CO2 can deliver an extra 30% of crude from oilfields with the added benefit that the gas is then sequestered permanently in the ground.
“Carbon Engineering’s direct air capture technology has the unique capability to capture and provide large volumes of atmospheric CO2,” said Occidental Petroleum’s Senior Vice President, Richard Jackson, in a statement.
“This capability complements Occidental’s enhanced oil recovery business and provides further synergies by enabling large-scale CO2 utilisation and sequestration.”
One of the other investors in Carbon Engineering is BHP, best known for its coal mining interests.
“The reality is that fossil fuels will be around for several decades whether in industrial processes or in transportation,” said Dr Fiona Wild, BHP’s head of sustainability and climate change.
“What we need to do is invest in those low-emission technologies that can significantly reduce the emissions from these processes, and that’s why we are focusing on carbon capture and storage.”