Battery-powered regional aircraft being developed by Pratt & Whitney could be used in NZ. Image / Supplied
Engine maker Pratt & Whitney says the development of sustainable aviation fuel isn't happening as quickly as it wants, despite growing moves by governments to support the change.
Technical complexity, a shortage of feedstock, infrastructure and production capacity are all challenges, but the development of alternatives to jet kerosene hasbeen gaining pace, especially in the past two years.
Developments include drop-in liquid sustainable aviation fuels (Saf) made from a variety of feedstocks, battery-powered planes for shorter routes and hydrogen for long-haul flights.
Connecticut-based Pratt & Whitney has been researching alternative ways to fuel its engines since 2005.
Chief sustainability officer Graham Webb says the wide-scale replacement of traditional fuel is necessarily slow.
A drop-in Saf - one that uses the same airport infrastructure as existing fuel and doesn't require engine modification - must meet about 40 technical criteria and go through many layers of regulatory approval. Saf is blended with Jet A-1 fuel, usually at about 50 per cent.
'We're flying people at tens of thousands of feet and everyone expects to get there," Webb told the Herald. "With these new technologies, you need to make sure that you understand them completely and make them safe."
Although flights with Saf account for just over 1 per cent of all flights around the world, production has increased quickly since 2019, with more airlines signing offtake agreements.
Last month Singapore Airlines signed up to a 1000-tonne Saf pilot scheme at Changi Airport using fuel supplied by Neste and blended with refined jet fuel at ExxonMobil's facilities in Singapore. Qantas this year signed an offtake arrangement with a United States supplier for transpacific flights from 2025.
No Saf is yet available in New Zealand and because of high start-up costs it can be up to four times the price of traditional jet fuel.
Air New Zealand says that with the right policy and investment settings, Saf production could be made viable in this country, and the commercial gap against fossil fuels can be narrowed.
Pratt & Whitney works with the airline which says analysis carried out by the Saf Consortium (Air New Zealand, Z Energy, Scion, LanzaTech and LanzaJet) shows there is a pathway to create a New Zealand domestic industry to meet half of this country's aviation fuel demand by 2050, supported by a domestic feedstock supply chain. This could also be supplemented by imported Saf.
While overseas governments are changing regulatory settings to encourage Saf development - including moves to bring in tax breaks for its use in the US - in New Zealand it's more a case of watch this space.
A spokeswoman for Energy and Resources Minister Megan Woods said there was not yet anything to add to what she said in March. Woods said then that a feasibility study into commercial Saf production was underway and some results were expected to be released next year.
Webb said he couldn't comment on what the New Zealand Government was doing, but said sustainable aviation was critical for this country, where the geography requires a lot of air travel, both domestically and internationally.
New Zealand had natural advantages with high amounts of waste biomass for Saf production and more than 80 per cent renewable electricity to produce "green" hydrogen. More sustainable travel was also in demand.
"So definitely, that would drive increased demand for air travel and you have a lot of renewable energy sources and a lot of opportunities to make use of those sustainable aviation fuels should you decide to do that, but there is a significant investment that's required."
While most Saf is blended to about 50 per cent, Pratt & Whitney and plane-maker Embraer this year successfully tested an aircraft using 100 per cent Saf.
The test, with one engine running on pure Saf, validated that Pratt & Whitney's GTF engines and the E-Jets E2 family can fly on both engines with blends of up to 100 per cent SAF without any compromise in safety or performance. The aircraft completed two days of ground tests at Fort Lauderdale in Florida, culminating in a 70-minute flight test.
In May Pratt & Whitney Canada announced a battery supply deal with electric aviation company H55 for a regional hybrid-electric flight demonstrator programme.