Published by Flightnook Team on

4th Generation Cleaner Fuels: From Carbon in the Air

Flightnook - Air
Biofuels are energy resources made from organic matter. Fossil fuel burning is the top cause of greenhouse gas emissions, and the climate crisis. Finding cleaner, carbon-neutral energy is a top priority for those who care for the environment, and by extension, humanity.
Every year since 2009, the global number of air passengers have increased according to International Air Transport Association (IATA). All these airplanes fly on kerosene, a cheap fossil fuel. Currently second generation biofuels are the best available means to decarbonize flight.
Developments in electrofuels made from electricity, carbon, and hydrogen provide an exciting future path to make air travel a more sustainable tourism option.

Why not follow Elon Musk and make electric airplanes?

Harbour Air, a seaplane company based in Vancouver retrofitted their internal combustion engines with batteries! They’re beginning the transition to the first all-electric fleet.
This is very inspiring but they were able to do it because going electric makes business sense for them. On a given year Harbour Air flies 500,000 people in 40 propeller airplanes for short haul flights. CEO Greg McDougall recognized this, “we were in this rather unique position of having short stage lengths and single-engine aircraft that require a lot less energy.”
The Paris Air Show summer 2019 showcased a host of startups working to electrify flight. These innovations keep the advantages of air transport but are limited to short distances because batteries have a much lower power-to-weight ratio than fuel.
Jet fuel has an energy of 11,890 watt hours per kilogram whereas top lithium-ion batteries have around 250 watt hours per kilogram. Technological developments will be needed to electrify a world fleet, something that will happen closer to 2050 than now. Until then internal combustion engines are needed for transcontinental flights.
TLDR; Batteries will be a solution for business short flights or Northwest island hopping, but not for flights longer than 500 miles (804km).

What are power to liquid fuels?

Electrofuels or power to liquid fuels (PtL) are synthetic liquid fuel created from electricity, carbon dioxide from carbon capture, and water. This carbon is mixed with hydrogen, and fed into a Fischer-Trope synthesis to produce e-fuel.
Flightnook - Electrofuels
Source: LBST/BHL 2016
Carbon Engineering in Squamish, British Columbia is the first firm to produce biojet from carbon capture. Their proof of concept was demonstrated in 2018 and the fuel can be mixed with today’s conventional jet fuel, making it “drop-in” compatible.
SAF + Consortium, Quebec group, recently qualified for the second round of Canada’s Sky’s the Limit Challenge by producing jet fuel from industrial emissions. This challenge spurred alternative energy companies to produce aviation biofuel, it allows any type of feedstock that’s not a fossil resource.

Challenges That Remain

Power-to-liquid fuels remain more expensive than fossil resources. The biggest expense comes from electricity to power the processes. We agree with what was outlined in a Transport & Energy release, “electrofuels promise clear climate benefits but only when produced from zero carbon renewable electricity.”
With Carbon Engineering in B.C. this electricity comes from water.
Flightnook - Scalability
Source: LBST/BHL 2016
Any electrofuel plant also must ensure their CO2 feedstock comes from the air, as Carbon Engineering from B.C. does. Alternative energy resources could technically be CO2 of fossil or biogenetic origin.
Though producing e-fuels from CO2 in the air is more energy-intensive, it avoids the potential problem of knitting carbon capture to a fossil industry. In any business case, carbon capture should not setback decarbonization of other industries.
On an individual level Flightnook enables individual fliers to lower their emissions and support local clean fuel providers, like Carbon Engineering or SAF. We empower passengers to demand cleaner flight.

Benefits of E-Fuels

Drawing carbon from the air to make fuel?! Wow!
These e-fuels require less water than third generation (algae) and first generation biofuels. Also, e-fuels need less land than first and second generation biofuels and don’t encroach on agriculture.
Further, unlike the hybrid electric planes above, these e-fuels can be used with existing infrastructure. This means they can be used immediately without scrapping old airplanes and equipment.
They burn cleaner, are carbon-neutral, and provide the possibility of a truly sustainable holiday. Out of all the developments explored in this series these fuels offer the greatest scaling potential.
Their only downside is the electricity they require to process, but in countries like Canada where 60% of energy comes from hydropower, we look forward to these developments of cleaner fuel.