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Currently , most sustainable aviation fuel is derived from vegetable oil , commonly known as ‘ HVO ’ fuel , using the HEFA process . This is largely because it ’ s the easiest . The vegetable oil molecules are fairly close to jet fuel , already being long chains of carbon and hydrogen with little oxygen or other contaminants . First the small amount of oxygen is removed , and then the hydrocarbon chains are saturated , isomerized , and cut to the right lengths for jet fuel .
However , growing concerns about land use and scalability are prompting a diversification of feedstocks . Even with some demand destruction for flying , the demand for SAF is huge and it is now widely accepted that HEFA fuel alone cannot be scaled to the levels required because of the competition with food and biodiversity . Alternative production processes are emerging , which use various sources of carbon-based waste , often called second-generation biofuels or wastebased fuels . The complexity and variability of these waste streams and the difficulties in aggregating and converting them to jet fuel means they have both technology and feedstock challenges . Given this , there is growing excitement in processes which use
CO 2 and green hydrogen as the feedstock , so called e-fuels or Power to Liquids ( PtL ).
In using CO 2 as the feedstock along with green hydrogen from renewable energy , e-fuels or Power-to-Liquids ( PtL ) have the potential for scale with minimal impact on land use . The core challenge for e-fuels currently is cost . First , the green hydrogen cost is key , and this depends on the green electricity price , as well as the cost of reliable low-cost electrolysers . The good news is both these are reducing as the industry scales . Second , you need low-cost pure CO 2
. If the CO 2 is biogenic or captured from the air ( DAC ) the process is circular , but in the short to medium term fossil or mineral CO 2 can also be used . Using fossil or mineral CO 2 in the process is not circular ,
but it means getting two uses out of some of the carbon that was dug up before it ends up in the atmosphere and still reduces emissions significantly . The good news is the CO 2 capture industry is increasingly mature and low-cost , and pure captured CO 2 sources are becoming more common . Finally , there is growing understanding of the conversion to fuel and how this is far simpler than most expect .
This is what we are focused on at OXCCU through our simplified , one-step process that converts CO 2 and H 2 into SAF . We have shown that it ’ s possible to make jet fuelrange hydrocarbons in a single step with high conversion and selectivity . Modelling completed by independent researchers from Imperial College London , through Imperial Consultants , has shown that OXCCU ’ s onestep process significantly reduces operational costs due to higher selectivity yield in the jet fuel range , has a 50 percent lower capital cost and has a reduced environmental impact .
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