Fifty years ago, the aviation industry focused on speed and capacity, both of which guzzled fuel and produced high volumes of greenhouse gases. Today, however, the industry’s focus has shifted 180 degrees – to sustainability and fuel economy.
Jetliners built by Airbus and Boeing have reduced fuel burn by 70% over the past 50 years. Carbon dioxide (CO2) emissions have dropped by 80% in that time, and nitrogen oxide emissions by 90%. Airliners also are 75% quieter, due largely to advanced engine and materials technologies.
As a result, large passenger aircraft are more ecofriendly per passenger mile than almost any other mode of transportation, even with a massive increase in travel demand. Today, aviation CO2 emissions account for about 2% of total global carbon dioxide emissions.
“The industry is moving faster than many people thought possible, especially when it comes to new technology,” said Amanda Simpson, vice president of research and technology for Airbus Americas.
If aviation is to do its share in reducing emissions under the Paris agreement on climate change, however, it must cut carbon emissions by another 80% by 2050. That would bring the industry to half of its 2005 emissions. Although air traffic is anemic in the wake of COVID-19, demand is expected to resume in three to five years and then continue growing, meaning reduced emissions must be achieved despite adding thousands of new aircraft – albeit much greener ones – to the global fleet over the next 15-20 years.
Our target is to have a carbon-neutral airplane in 2035 instead of 2050Bruno Le Maire
Minister of Economy and Finance, France
All of the airframe manufacturers are chasing solutions. Between 2012 and the end of 2019, for example, Boeing’s ecoDemonstrator initiative – part of the company’s accelerating focus on securing long-term sustainable growth – used a 777-200 aircraft to test 50 discrete fuel-efficiency technologies.
“We remain committed to the ecoDemonstrator program and will conduct additional testing across multiple platforms to help further innovation that makes flying more sustainable,” a Boeing official said.
WILL PROGRESS HAPPEN FAST ENOUGH?
Although such initiatives are helping the industry to achieve average pollution-reduction rates of 1% to 1.5% per year, it’s not good enough, Rolls-Royce Chief Technology Officer Paul Stein said. “Right now, we are not keeping pace with reducing net CO2 emissions,” he said. “More must be done.”
Airbus’s Simpson agrees: “Looking at the long-range growth curve, the industry is not on a path to meet the 2050 goal. We’ve got to stay focused on innovation.”
To step up the pace, sustainability solutions now in development will span a combination of technologies. These include lighter, more aerodynamic airframes and deployment of next-generation air traffic management systems that will permit commercial carriers to fly the most direct routes, burning less fuel and generating fewer emissions per passenger mile.
New fuel sources, in particular, are getting significant attention. In fact, collaboration on fuel development is part of a sustainability agreement struck in 2009 by airframe and engine manufacturers Airbus, Boeing, Dassault Aviation, General Electric, Rolls-Royce, Safran and United Technologies (now Raytheon Technologies after merging with Raytheon).
“We must start growing the use of sustainable fuels, and we must encourage their use at a greater pace than ever before,” Stern said, speaking at the International Society for Air-Breathing Engines conference in Canberra, Australia.
Boeing Chief Technology Officer Greg Hyslop added: “From the fuel perspective, we have to get incentives in place for the oil industry, and we have to get that going now.”
Also in the early stages of development: hydrogen fuel cells that could power some segments of a passenger jet’s flight.
The French government, for example, plans to invest 15 billion euros (about US$17 billion) over three years to support research into environmentally friendly technology, with the goal of developing a hydrogen-powered successor to the Airbus A320.
The percentage reduction in carbon emissions that the aviation industry must achieve by 2050 to do its share in reducing emissions under the Paris climate change agreement.
“Our target is to have a carbon-neutral airplane in 2035 instead of 2050,” said Bruno Le Maire, France’s Minister of Economy and Finance. For their part, industry executives doubt that a radical switch from conventional jet engines could be ready for service by the mid-2030s. However, more R&D spending is being funneled into decarbonizing commercial aviation than ever before, and momentum is building.
Following a six-month study on the use of hydrogen as a primary aviation fuel, research analyst firm McKinsey concluded in June 2020 that developing a carbon-neutral airplane by 2035 is within reach, though the quest will be challenging. The study focused on liquid hydrogen, which it deems better suited to most of aviation.
The German government also believes hydrogen could play an important role in the greening of civil air transportation. It is investing 6.8 billion euros (about US$7.7 billion) in what it calls its “national hydrogen strategy,” which supports the use of hydrogen in aircraft propulsion and hybrid-electric flying.
The initiatives in both France and Germany align with the European Commission’s plan, announced earlier in 2020, to launch a Clean Hydrogen Alliance as a centerpiece of a new strategy to accelerate the decarbonization and digitalization of Western European industries.
ADVANCING TECHNOLOGY, BUT SAFELY
Developing more sustainable fuels isn’t the industry’s only focus. Major players are focused on electric and hybrid-electric propulsion of light aircraft and large-scale demonstration vehicles, which have made the most progress.
In 2017, for example, Airbus and Rolls-Royce recognized that emerging technologies for the future of flight – including batteries and electric motors – could lay the groundwork for exponential development of non-traditional propulsion. As a result, they launched a project called E-Fan X. It was phased out in early 2020, but Simpson believes the knowledge that came out of the project was invaluable and will serve as a mid-term solution to the challenge of sustainable aviation. “Our goal is zero emissions by the mid-2030s,” she said.
While Simpson is optimistic, she is quick to emphasize that Airbus won’t rush to deploy new technology. Safety must come first: “It’s at the core of everything we do,” she said.