Airbus and Boeing embrace contrasting strategies in drive for cleaner air transportation
By Cat Hofacker|February 11, 2021
Both companies seek renewable fuels and fresh aircraft designs, but priorities differ
As they cope with the financial toll of the coronavirus pandemic, Airbus and Boeing are embracing distinct strategies for meeting an even greater challenge: decarbonization.
The air transport industry has had a long-standing goal of reducing its carbon footprint by 50% below 2005 levels by 2050, and last year the industry’s Air Transport Action Group said a “net-zero” footprint might be possible by 2060 or 2065.
Neither company disputes the urgency of making progress toward those goals.
“Society is demanding it,” said Amanda Simpson, vice president of research and technology at Airbus Americas, during a Monday AIAA webinar.
Last September, Airbus pledged to bring one of three conceptual hydrogen-based designs to service by 2035, an effort the company estimates will cost billions. Simpson said this “quite aggressive” approach would be worth it because of the enormous impact foreseen for the new technology.
When liquid hydrogen fuel mixes with oxygen for combustion, no carbon dioxide is produced. Aircraft do produce other greenhouse gases including nitrogen oxides, but the 2050 goal focuses on reducing carbon dioxide because it has the longest duration effect on atmospheric warming.
Airbus’ new designs would run on green hydrogen, meaning the energy to produce the fuel would come from renewable sources such as wind or solar.
Boeing, by contrast, charted a course last month to accelerate today’s early-stage rollout of sustainable aviation fuels, or SAFs, by pledging that by 2030 all the aircraft it sells will be certified to run entirely on these fuels derived from crop residue or other raw materials, rather than the 50/50 blend approved so far by the ASTM International standards body.
“Sustainable aviation fuels are needed to deliver the bulk of” the decarbonization goal, Boeing’s director of sustainability strategy Sean Newsum told me. “If battery, electric and hydrogen technologies could come into play and can contribute to emissions reductions, that’s fantastic, but we can’t count on that as being a solution.”
Airbus, meanwhile, also believes strongly in SAFs and is exploring how its planes could fly on higher blends of the fuel.
Jet engines running on SAFs emit about the same amount of carbon as when they burn conventional fossil fuels, but the net increase in atmospheric carbon is minimal. Why? As aircraft burn SAFs, nearly equivalent amounts of carbon in the form of C02 are absorbed from the air by, for example, crops whose residue is one raw ingredient for SAFs. Burning fossil fuels by contrast continually spews carbon dioxide into the air, carbon that previously was buried safely underground where it can have no impact on the climate.
Jets that today are certified for the 50/50 blend of SAFs and conventional fuels could very well still be in service in 2050. For that reason, certifying jets to run on 100% SAF would be the fastest way to reduce their impacts on atmospheric carbon, Newsum said.
In at least one expert’s view, a heavier emphasis on SAF comes with fewer technical risks.
“For Boeing to aspire to get the jet engines certified to run on 100% synthetic fuel” — a synonym for SAF — “it is positive, but it’s not the same scope of exercise” as designing and certifying a hydrogen-fueled aircraft, said consultant Chris Malins, who at his one-man London consulting firm Cerulogy focuses on alternative fuels.
Today, SAF blends are certified as drop-in fuels, meaning modifications to the engines are not required.
By contrast, Airbus’ proposed hydrogen planes would be new-builds, with electric motors powered by hydrogen fuel cells supplementing thrust from modified turbine engines that would burn liquid hydrogen fuel. At four times the volume of jet fuel, “you cannot store hydrogen in the wings” of an aircraft like other liquid fuels, said Arjan Hegeman, who leads GE Aviation’s Advanced Technology Organization, during the AIAA webinar. “It’s liquefied under high pressure, cooled, so it will need some type of cylindrical tank that sits somewhere in the fuselage.”
There’s some doubt as to whether the technical challenges of hydrogen aircraft could be worked out by 2035, said Dan Rutherford, director of aviation programs at the Washington, D.C., nonprofit the International Council on Clean Transportation.
“It’s concerning to me because there’s a potential that they’re overpromising and they will underdeliver in the end,” he said of Airbus.
Airbus chief technology officer Grazia Vittadini addressed the risk question when the hydrogen initiative was announced, saying “when it comes to environmental responsibility, we do not have a choice.”
Does the air transport industry need to rally around a single strategy for prioritizing spending on technology versus SAFs?
“There is no need” to do so, Hegeman said. He predicted that SAFs and new technologies including hydrogen-powered aircraft will play large roles. “Where we do need common approaches is more from a government perspective,” he said, such as establishing common regulations.
In terms of policies, consultant Malins said the Airbus and Boeing plans could get a boost from political goals to reach a net-zero economy by 2050, pledges made by dozens of leaders including those in the European Union and U.S. President Joe Biden. Politicians anxious to meet that goal might provide tax breaks or funding to boost production of SAFs and hydrogen fuel, he said.
As matters stand, the air transport industry believes it would need an additional 10 to 15 years to achieve net-zero for the sector.
“If you want to get more sustainable aviation fuel into airplanes in the next 10 or 20 years, you need to have people actually investing in capacity to do it and technologies that will do it sustainably,” meaning without generating carbon emissions, Malins said. “And if that’s going to happen, you need to have intelligent policy that creates value for the people who invest in it.”