ENERGY OUTLOOK

The Alternative Aircraft Fuel

by Royce Lowe

Sustainable Aviation Fuel (SAF) is jet fuel produced from waste oils derived from biological sources (e.g., cooking oil, other non-palm waste oils from plants, agricultural residue, or non-fossil CO2), or solid waste from homes or businesses (e.g., packaging, paper, textiles, food waste). Commercial aircraft are currently certified to operate on a maximum of 50% SAF blended with conventional jet fuel, though aircraft and jet- engine manufacturers have made commitments to increase the effective percentage of SAF.

SAF is a biofuel used to power aircraft that has similar properties to conventional jet fuel but with a smaller carbon footprint, depending on the feedstock and technologies used to produce it, SAF can reduce life cycle GHG (greenhouse gas) emissions dramatically compared to conventional jet fuel. Some emerging

SAF pathways even have a net-negative GHG footprint. SAF’s lower carbon intensity makes it an important solution for reducing aviation GHGs, which make up 9%–12% of U.S. transportation GHG emissions, according to the U.S. Environmental Protection Agency. An estimated 1 billion dry tons of biomass can be collected each year sustainably in the United States, enough to produce 50–60 billion gallons of low-carbon biofuels. These resources include: corn grain, oil seeds, other fats, oils and greases, agricultural and forestry residues, and wet wastes (manures, wastewater treatment sludge.)

In the latest step by the commercial aerospace sector to reduce carbon emissions, Pratt & Whitney Canada agreed to work with regional aircraft builder ATR on an initiative to achieve 100% Sustainable Aviation Fuel (SAF) readiness for PW127 series engines by 2025. Their agreement will cover the new PW127XT engine that will power upcoming ATR aircraft. ATR is a Franco-Italian aircraft manufacturer headquartered near Toulouse. It is a 50-50 joint-venture of Airbus and Leonardo that supplies twin-engine turboprop aircraft for regional service, principally the ATR 42 and ATR 72 models – both of which are powered by PW127 engines.

“Our collaboration with ATR will be underway throughout 2023 and 2024, and builds on our recent 100% SAF test flight with Sweden’s Braathens Regional Airlines, which was an industry first for regional aviation,” said Anthony Rossi, Vice President of Sales and Marketing, Pratt & Whitney

Canada. He continued, “Alongside our efforts to continually enhance aircraft engine efficiency, SAF has a critical role to play on the journey to achieve the aviation industry’s goal of net-zero CO2 emissions by 2050. While all Pratt & Whitney Canada engines have already been certified for 50% SAF blends for more than a decade, ensuring readiness to operate with 100% SAF blends in the future will allow us to maximize their potential for decarbonization.”

Nathalie Tarnaud Laude, ATR’s Chief Executive Officer, added: “It is our collective responsibility as an industry to continue taking action to ensure that the vital connections provided by our aircraft across the globe are operated sustainably. We have recently demonstrated with our collaborators, Braathens Regional Airlines and Pratt & Whitney Canada, that ATR aircraft are SAF ready. Now, we need to continue to join forces to increase SAF availability as part of our common journey towards net-zero.”

GE Aviation reported the results of a successful test of its Passport turbofan engine using 100% Sustainable Aviation Fuel (SAF). It’s the latest result among multiple efforts to lower carbon emissions in commercial and private aviation. The GE Passport engine is a smaller-scale version of the LEAP engine series developed by CFM International (a GE Aviation joint-venture with France’s Safran) developed for long-range business jets and introduced in 2018 for the Bombardier Global 7500 and 8000 series jets.

“As our testing shows, the Passport engine, like all GE engines, can operate on approved Sustainable Aviation Fuel today and in the future,” according to Melvyn Heard, President of the Passport engine program. “Our customers can be confident that the Passport engine can help meet their sustainability goals to reduce CO2 emissions in flight, thanks to the Passport’s more fuel-efficient technologies compared to previousgeneration business jet engines and its ability to operate on lower-carbon fuels.”

Other recent SAF tests of GE/CFM International engines include a United Airlines jet flight of a Boeing 737 MAX 8, with SAF powering one of two LEAP-1B engines : a Boeing ecoDemonstrator test flight using 100% SAF in CFM LEAP-1B engines; and a 100% SAF-fueled FedEx flight of a Boeing 777F, powered by two GE90 engines.

SAF is definitely in its infancy. Its future will depend on the willingness of those involved to produce gargantuan quantities of the stuff.

Author

profile: Royce

Lowe, Manufacturing Talk Radio, UK and EU International Correspondent, Contributing Writer, Manufacturing Outlook . n

MARCH 2023