Renewable fuels from direct air capture could soon compete with petrol, diesel, jet fuel

Source: RenewEconomy

It may soon be possible to produced zero-emission petrol (gasoline), diesel and jet fuel from the direct air capture of CO2 and water vapour in a way that will compete with fossil fuels in price. A Silicon Valley company called Prometheus led by Rob McGinnis is aiming to do this. The process has been presented recently in the journal Joule. 

Although the science of making fuels from CO2 and water has been known for some time it has been far too expensive. The Prometheus process has CO2 and water in an aqueous electrolyte which is reacted with a copper catalyst to directly make alcohols such as ethanol, butanol, propanol, etc. with the power coming from wind and/or solar electricity. Originally, the alcohols would be extracted via distillation, which is expensive, but Prometheus has invented a carbon nanotube membrane that can do this economically. (Launch HN, 2019). 

This fuel can be used with existing infrastructure for cars, trucks, ships and aeroplanes, so can be employed quickly. It is not seen as a replacement of electric or hydrogen transport but as an addition to help speed up the transition to clean transport, particularly for heavy transport. Once the green fuel is cost competitive there is still one main drawback and that is that huge amounts of renewable electricity will be required. But one advantage is that the process can be stopped and started easily to fit in with the fluctuations in electricity supplies and costs (i.e. it would be another way to store excess renewable energy). 

References: 

- Prometheus: https://www.prometheusfuels.com/ 

- Remove CO₂ from air and turn it into gasoline. Launch HN: Prometheus (YC W19). 

- Renewable fuels could soon be cost competitive with petrol, gasoline, RenewEconomy, March 19, 2020. 

- CO₂-to-fuels: renewable gasoline and jet fuel can soon be price competitive with fossils fuels, Joule, Commentary, Vol. 4, Iss. 3, pp 509-511, March 18, 2020.