Boeing has committed that its new commercial aircraft will be able to burn 100% “sustainable” fuel by 2030, an achievement Boeing describes as essential to meeting industrywide carbon reduction goals by 2050.
The Chicago-based airframer says it continues studying other carbon-reducing technologies, such as hybrid-electric and hydrogen propulsion systems.
But it describes sustainable aviation fuel (SAF), which includes biofuel, as the prime means by which the sector can reach IATA’s goal of, by 2050, cutting airline emissions to half of 2005 levels.
“We are putting this emphasis on sustainable fuels because we believe this is the most-feasible way to reach our ambitions,” says Boeing director of sustainability strategy Sean Newsum. “We need to make [sure] that jet fuel, in that 2050 timeframe, is as sustainable as possible.”
Sustainable fuels were previously known as biofuels, renewable fuels and alternative fuels. Biofuels are produced from “bio-based feedstock” like agricultural and forestry residues, chicken tallow and cooking oils, Newsum says. Sustainable fuels can also be derived from solid waste, gasses generated by steel mills and CO2 pulled from the air by a process called direct air capture.
Burning fossil-based fuel releases into the atmosphere carbon that would otherwise have been trapped underground. But burning biofuel releases carbon that had previously been absorbed from the atmosphere by plants, making the fuel’s CO2 impact “almost neutral”, according to IATA.
Biofuel’s benefits can be negated if land must be cleared of vegetation to grow crops used to produce biofuel, according to the US Energy Information Administration. However, IATA says sustainable fuel, as it defines the term, cannot be produced from “anything that diverts land use from food crops, or destroys forests, or consumes too much fresh water, because that’s simply not sustainable.”
Currently, airlines can only burn sustainable fuel that has been blended with fossil-based fuel, and the percent of sustainable fuel in those blends cannot exceed 50%.
That is because sustainable fuel can effect aircraft and engines – notably seals – differently than fossil-based fuel. Also, higher-percent blends do not meet fuel standards set by organisations like ASTM International in the USA and the UK’s Defence Standardization, says Newsum.
Airlines have been working at differing paces to incorporate sustainable fuel into their operations. But Newsum says the globe’s carriers burned only about 18.9 million litres (5 million USgal) of sustainable fuel in 2019 – less than one tenth of a percent of the 364 billion litres burned by all airlines.
“Boeing’s commitment is to determine what changes are required for its current and future commercial airplanes to fly on 100% sustainable fuels, and to work with regulatory authorities and across the industry to raise the blending limit for expanded use,” the company says.
Reaching the 100% goal will require Boeing to study the effect of sustainable fuels on its aircraft. The manufacturer might need to change some aircraft systems, or the industry might seek to alter fuel standards, either of which could require sign off by the US Federal Aviation Administration, Newsum says.
Boeing intends to partner on the project with engine makers. GE Aviation, CFM International and Pratt & Whitney did not immediately respond to requests for comment.
Tricky hurdles involving sustainable fuel costs and production levels must be overcome. But Newsum says a starting point is to ensure aircraft can actually burn 100% sustainable fuel.
Boeing set 2030 as its deadline because aircraft then will likely still be flying by 2050. Newsum says that despite advances in hybrid-electric and hydrogen-power technology, the airline sector in 2050 will still run primarily on jet fuel.
“Sometime in the 2030s and 2040s, when we are accelerating the use of sustainable fuels, and the volumes get to be large, we want to make sure the airplanes in the global fleet are not inhibiting the global sustainable fuel adoption,” he says.
Newsum declines to say how much money Boeing will dedicate to the effort.
“We will be sharing progress as we go,” he says. “We don’t have any of the specific steps or timelines we are ready to state right now.”
Boeing has been working on sustainable fuel projects for more than a decade. The company contributed to an effort it says led to the first flight of a biofuel-powered aircraft – a Virgin Atlantic 747 – in 2008.