Grounded: Eviation’s Alice, a concept that had more questions than answers. Credit: Eviation.
By Scott Hamilton
Feb. 18, 2025, © Leeham News: Universal Hydrogen. Lilium. Volocopter. Tecnam’s electric airplane. Airbus electric. Airbus hydrogen. ATR hybrid.
Eviation was just the latest alternative energy project to bite the dust.
And these are just the ones we’ve heard about.
Boeing declined comment on the status of its WISK autonomous electric air taxi. Its future may have as much to do with the company’s current financial condition and efforts to recover from a series of crises since the March 2019 grounding of the 737 MAX than with technology or business model concerns.
The alternative energy aviation industry, the soup du jour in recent years, is running out of gas, so-to-speak. LNA’s aerospace engineer, Bjorn Fehrm, predicted years ago that battery-, and hybrid-powered airplanes were concepts that wouldn’t fly and that hydrogen’s availability at airports is tough nut to crack.
The International Air Transport Association in October 2021 adopted a goal for the airline industry to achieve net zero carbon emissions by 2050. Aggressive milestones also were adopted. Included were ambitious goals to significantly increase the use of Sustainable Aviation Fuel (SAF), the path favored by Boeing.
Tim Clark, the president of Emirates Airline, said then, Don’t make promises you can’t keep.
The industry, it now increasingly admits, can’t keep these promises.
Failure is an option after all
Simply put, none of the technology is ready—and it won’t be for decades. As LNA has been writing for years, battery weight-to-power isn’t efficient. The life cycle of battery production and disposal remains environmentally challenged. eVTOLs must operate under visual flight rules and have endurance generally in the tens of miles. Battery-powered airplanes require charging infrastructure and have impractical range.
Hydrogen-powered aircraft have storage issues on and to-and-from the airplanes; and high-volume production is completely absent.
Air New Zealand gave up its goals of making progress toward net zero. ANA and Japan Airlines are taking different approaches amid slower than expected progress. Production facilities remain anemic. Feedstock isn’t remotely adequate to meet demand. Depending on how reliant production is on land-based feedstock, SAF conceivably is worse for the environment than Jet A fuel. SAF is more expensive than Jet A fuel, measured in multiples. Synthetic SAF is even more expensive.
SAF use globally, and even among participating airlines, is only a fraction of 1%. This hasn’t changed since IATA’s 2021 initiative, nor from decades before.
Replacing current airplanes will take generations
Environmental advocates so far fail to fully recognize that the aviation industry flies 25,000 airliners each day, and that this amount of airplanes will take generations to replace with much more efficient airliners. Airbus A320ceos and Boeing 737 NGs—the older generation single-aisle airplanes dominating operations today—will be flying for years to come. The last ceo was delivered around 2018. The last 737 NG was delivered around 2019. Typical passenger service for an airliner is around 25 years. The older generation single-aisle aircraft will likely be in service until 2041 and 2043, respectively. Freighters can fly up to 40 years before retirement.
The A320neo and 737 MAX are expected to remain in production throughout most of the 2030 decade, perhaps to 2040. This means the last of these airplanes won’t exit passenger service until around 2065.
Widebody aircraft often have similar life cycles.
What’s the answer?
In ground transportation, there is a principle called multi-modal. This means transportation is a combination of cars and trucks, buses, trains, light rail, motorcycles, bicycles and walking. In commercial aviation, work must continue on alternative energy sources, but real advances probably are a generation or more away.
This means that the next generation of airplanes and engines, whatever shape these take, must have significant improvements to have a real positive impact on the environment.
JetZero, a start-up company, is developing the first passenger Blended Wing Body aircraft, for the 250 seat class. Officials claim it will offer fuel consumption that is up to 50% better than Boeing 767s and Airbus A330ceos it’s intended to replace. LNA is skeptical of this claim, but this isn’t the biggest challenge facing the new company. It has only a fraction of the billions of dollars needed to bring the BWB to the market.
Consultants believe the best chance for the project is for JetZero to be purchased by Boeing or Airbus, which have the muscle to do so. Boeing is hardly able to do so for years to come, and in any event, it has its own BWB research acquired in the 1997 merger with McDonnell Douglas. Airbus is skeptical of the BWB.
Under the previous CEO David Calhoun, Boeing seemed enamored with a Transonic Truss Brace Wing (TTBW) concept. Mated with new conventional engines, Calhoun said the airplane might be able to bring 25%-30% better economics. But there are a lot of certification challenges to a high wing airplane (like water and wheels-up landings) and flight characteristics associated with the super-wide wingspan. It’s not at all clear that this will be the Next Boeing Airplane (NBA).
The next single-aisle airplane will likely be a conventional tube-and-wing design.
Engines are the key—as always
Engines are the key to the next airplane. They always are. Pratt & Whitney and Rolls-Royce are pursuing improvements in conventional engine technology. These might improve fuel consumption by around 10%. CFM International (GE Aerospace and Safran) is placing its bet on the Open Fan RISE engine. The Open Fan is a refinement of the Open Rotor counter-rotating propfan engines under study since the 1980s. GE says the Open Fan will result in a 20% improvement in fuel burn (and with it, emissions). But there remains some real skepticism that all the 1980s vibration, noise and blade-out concerns have been solved. GE and Airbus plan to initiate flight testing on an A380 in 2027.
Improvements in the airframes are harder to come by. Aerodynamics for conventional tube-and-wing aircraft can only incrementally improve fuel efficiency. Weight is the key. So, new materials and production methods may become major contributors.
These are the realities. The alternative energy pie-in-the-sky has come down to earth.
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