An environmental-transportation research group is warning that sustainable aviation fuel (SAF) will do too little to curb carbon output and that manufacturers must start delivering zero-emission aircraft next decade if airlines expect to meet their 2050 net-zero emissions goal.
That is according to a new report from the International Council on Clean Transportation (ICCT), which warns that the industry will miss the goal if Airbus and Boeing’s next-generation jets are only incrementally more efficient, as they seem likely to be.
“If you take net-zero by 2050 seriously, it means that all new aircraft delivered after 2035 need to be net-zero over their entire operational lifetimes,” says ICCT programme director Dan Rutherford, who co-authored the report, released on 18 July.
The Washington, DC research group reached that conclusion based on factors including aircraft life-cycles – jets flying now will likely still be flying for decades – and the rate at which airlines burn more SAF.
The report urges manufacturers to dramatically boost their investment in development of zero-emission aircraft, such as those powered by hydrogen or electric propulsion systems.
“While SAF blends and fuel efficiency can cut CO2 emissions by more than half, they will not be enough to deliver net-zero aviation,” the group says. “Manufacturers also need to develop new aircraft types that don’t rely upon fossil fuels.”
Global airline trade group IATA committed in 2021 that the sector will achieve net-zero carbon output by 2050. It is banking on several means of getting there, including introduction of next-generation more-efficient aircraft, efficiencies gained through operational changes, carbon offset and capture programmes and, critically, increased use of SAF.
IATA projects that SAF will deliver the most benefit, accounting for up to 65% of the carbon airlines will need to eliminate. SAF is typically biofuel but can include a variety of in-development alternative fuels touted as having reduced carbon footprints.
Airbus and Boeing have committed that all their aircraft will be certificated to burn 100% SAF by 2030. Current requirements prohibit aircraft from burning fuel composed more than 50% of SAF.
Despite promises, SAF’s viability remains in question. The fuel is several times more expensive than fossil-based jet fuel, and supply remains minuscule. Also, the vast expansion of production required for widespread use by airlines comes with environmental and societal risks, including those associated with converting land – such as forested areas or land used to grow food crops – to grow crops for SAF production.
ITTC’s report predicts demand will exist for 10,000-14,500 zero-emission aircraft through 2043, assuming manufacturers start offering such products next decade.
But major airframers do not appear to be moving in that direction.
Though Airbus and Boeing are widely expected to bring to market new narrowbody passenger jets in the mid-2030s, those aircraft are expected to be of relatively conventional designs, with fuel-burning engines.
Boeing chief executive David Calhoun has said his company’s next narrowbody offering, which remains undefined, must be 20-30% more efficient than the 737 Max.
Airbus has been studying hydrogen-powered aircraft for service entry next decade but has indicated such aircraft, if actually developed, would be smaller than and not compete directly with its existing products.
ICCT’s report comes the week Airbus released a forecast projecting the global fleet of commercial passenger and freighter aircraft will roughly double during the next 20 years, from 24,260 today to 48,230 in 2043. Boeing has forecasted a similar trend.
