It was back in 2011 that we first heard how Virgin Atlantic Airways was planning to use an eco-friendly aviation fuel made from captured steel mill waste gases. A successful test flight followed in 2016, and the fuel has now been utilized in a commercial flight for the first time.
Manufactured by project partner LanzaTech, the fuel is made by gathering carbon-rich waste gases from steel mills, then using bacteria to ferment the carbon into ethanol. Utilizing a catalyst developed at the Pacific Northwest National Laboratory (PNNL), oxygen is then removed from the ethanol in the form of water, after which the remaining hydrocarbon molecules are combined to form chains large enough for jet fuel, but without forming compounds that produce soot when burned.
A form of alcohol-to-jet synthetic paraffinic kerosene (ATJ-SPK), the end product was internationally approved as aviation turbine fuel this April. It can be used at up to a 50-percent blend ratio with standard, petroleum-based jet fuel. That hurdle having been cleared, the kerosene saw its first commercial use this Wednesday (Oct. 3rd), when it was used in a 5-percent blend to power a Virgin Atlantic Boeing 747 that flew from Orlando, Florida to London.
The fuel currently isn't being produced in sufficient volume to have provided enough for a higher blend ratio. That said, plans are now being made for a Georgia-based production facility that will be capable of producing millions of gallons of the ATJ-SPK annually, along with three plants in the UK.
"This fuel exceeds the properties of petroleum-based jet fuel in terms of efficiency and burns much cleaner," says John Holladay, PNNL's deputy manager for energy efficiency and renewable energy. "The technology not only provides a viable source of sustainable jet fuel but also reduces the amount of carbon dioxide emitted into the atmosphere."
Well, my question is, if it's so good, why can't it be used 100%, aside from availability? I think it's a great idea, but that they're leaving something out, info-wise.
Jet fuel is a surprisingly complicated product. As of date there is no drop-in replacement from alternative sources, and given the mixture that jet fuel represents, it'd be very unlikely to be developed.
Instead, there are two pathways to get to a usable alternative fuel: (1) certification of a mixture that meets the established standards for jet fuel, or (2) certification of the pure alternative fuel for use with existing and future power plants.
Obviously option 1 is massively less expensive than 2, and only takes years vs decades.
To date ATJ-SPK is only certified in mixtures of up to 50%. I'm not sure what drove that limit, but it could be anything from viscosity to density to flashpoint to freezing temperature and so on. Over time there will presumably be more operational experience from use of the product, and assuming the product is up to it, the mixture limits will certainly be relaxed.
Cost?