Features
6 Feb 18

Bill Gates wants to pull CO2 from the air

Pull CO2 from the air and use it to produce carbon-neutral fuel. It only takes about a dozen words to describe but is it feasible on a global scale? Carbon Engineering, a company set up by geoengineer David Keith with backing from Microsoft founder Bill Gates and oil sands magnate Norman Murray Edwards, has built a prototype plant to try just that, reports The Guardian.

The company first extracts CO2 from the air using Direct Air Capture, a system that can be described as artificial trees although there's no photosynthesis involved. Using a wall of giant fans, DAC systems extract CO2 from the air with chemicals that bind CO2 as air passes over them. When energy is added to the mix, the purified CO2 unsticks from the chemicals who can then be reused to capture more CO2 from the air.

Air to Fuels

In a next phase, the removed CO2 can be used to produce liquid hydrocarbon fuels through water electrolysis and fuels synthesis.

Carbon Engineering is extracting CO2 from the air at its plant in British Columbia but has been releasing it back into the air until now. The company has now begun directly synthesising a mixture of petrol and diesel using only CO2 captured from the air and hydrogen split from water with clean electricity, a process called Air to Fuels (A2F).

If Carbon Engineering succeeds in scaling the process up and producing fuel for little more than it costs to extract and sell fossil fuels today, they may have struck gold.

Negative emissions

But will it be enough to reach the goal of net zero man-made emissions by 2090 set by the Intergovernmental Panel on Climate Change? And even that goal will likely not be enough. If we want to avoid catastrophic climate change, emissions must become net negative, meaning more carbon is being removed than emitted.

Today, many countries are building on hope that negative emissions will be put to use at a large scale. However, cost remains an obstacle.

No insurance policy

In the journal Science, Professor Kevin Anderson of the Tyndall Centre for Climate Change Research and Glen Peters of the Centre for International Climate Research in Norway posited that the world should proceed on the premise that these technologies will not work at a large scale. Not to do so, they continued, would be a moral hazard par excellence. It would be more intelligent, they claim, to not use fossil fuels and not emit CO2 in the first place.

They wrote: “By the middle of the century, many of the models assume as much removal of CO2 from the atmosphere by negative emission technologies as is absorbed naturally today by all of the world’s oceans and plants combined. They are not an insurance policy; they are a high-risk gamble with tomorrow’s generations, particularly those living in poor and climatically vulnerable communities, set to pay the price if our high-stakes bet fails to deliver as promised.”

Picture: pilot plant rendering (Carbon Engineering)

Authored by: Benjamin Uyttebroeck