Electric Airplanes Won’t Make Much of a Dent in Air Travel for Decades to Come

Reason: Batteries are nowhere near able to sustain wide-body airliners over flights measuring in the thousands of kilometers

3 min read
Photo of a flying electric plane.

Exaggeration has become the default method for news reporting, and the possibility of commercial electric flight has been no exception, with repeated claims that these new planes will utterly change how we live.

In 2017, Boeing and JetBlue funded Zunum Aero, a U.S. company that promised nothing less than transforming air travel with short-haul electric planes capable of carrying 12 people–and doing it by 2022. Two years later Boeing declined to continue funding the project.

At the Paris Air Show in June 2019, the CEO of Eviation introduced Alice, a nine-seat commuter plane that had two pusher motors on the wing tips—a highly questionable design—and said, "This is not some future maybe…. It's operational." It was not. The first flight did not take place as advertised, and in 2021 the motors were relocated aft on the model fuselage.

Meanwhile, there is the Pipistrel Velis Electro, the first electric airplane to receive European Union flight certification. It is able to carry just two people, for only about an hour.

Illustration comparing the sizes of a Pipistral Velis Electro and a Boeing 787-10 in meters. More people, flying further have nearly doubled the passenger-kilometers traveled by air over the past decade. Short-haul flights on battery power, while undoubtedly convenient, would amount to a mere rounding error, not only for this metric but for the related one of carbon emissions. The Pipistrel Velis Electro, the first e-plane approved in the European Union, can carry two people for about 100 kilometers; the Boeing 787-10 Dreamliner can carry 336 people 11,750 km—about a 20,000-fold difference. James Provost

But overly ambitious goals and setbacks are not the question here; such early failures are to be expected in any new technical endeavor. The problem is much more fundamental. Having all-electric aircraft for short-haul flights would indeed be great, and it would provide critical services to millions of travelers living in small towns. Still, it would make only a minor contribution to what is truly a gigantic business.

Air traffic surged from 28 billion passenger-kilometers (pkm) in 1950 to 2.8 trillion pkm by the year 2000, a 100-fold rise. It then rose to nearly 9 trillion pkm before the pandemic intervened. Trillions of passenger-kilometers could be added so rapidly thanks to the advent of wide-body airplanes carrying 300 to 500 passengers per plane between the continents. Consider such flights, spanning about 6,000 kilometers between Europe and North America, 8,000 km between Europe and East Asia, and 11,000 km between North America and Asia—and compare them to short-haul affairs, say between smaller towns and the largest city in a state.

Large turbofan engines powering these planes are fueled by aviation kerosene that provides nearly 12,000 watt-hours per kilogram. In contrast, today's best commercial Li-ion batteries deliver less than 300 Wh/kg, or 1/40th the energy density of kerosene. Even when taking into account the higher efficiency of electric motors, the effective energy densities go down to about 1/20th. That's more than better batteries can bridge within the next decade or two.

During the past 30 years the maximum energy density of batteries has roughly tripled. Even if electrochemists should replicate that feat, providing us with 1,000 Wh/kg batteries in 2050, it would still fall far short of what's needed to fly a wide-body plane nonstop from New York to Tokyo, something that All Nippon Airways, Japan Airlines, and United Airlines have been doing for years with the Boeing 777. And while kerosene-fueled planes get lighter as they travel to their destination, electric aircraft will have to carry a constant mass of batteries.

Moreover, the airline industry requires massive investments. Pre-COVID estimates indicated that between 2018 and 2038 the combined market for new planes, together with the cost of their maintenance, repair, and associated training services, would be on the order of US $16 trillion. Such enormous outlays require long planning horizons, embedded in commitments to specific designs and aircraft orders.

This means that the industry's next few decades have already been decided. Because the average lifespan of both single-aisle and wide-body planes is just over 20 years, forthcoming purchases of new planes will expand the existing fleet at least by half—and all of the large commercial planes will rely on kerosene-fueled turbofans.

This article appears in the November 2021 print issue as "Electric Flight."

The Conversation (5)
Roland Kwee 01 Dec, 2021

To solve the climate problem, we could reduce emissions with a less luxury life style, or "go electric". This article shows that going electric is not that simple, while ignoring that electric energy is not without emissions. The author's conclusion, that the airline industry's next decades have already been decided, ignores the option of reducing this industry, similar to what happens during the corona pandemic. Flying less is not a tech problem and can be implemented today. Is it really needed for mankind to fill Boeings 787's with hundreds of people to fly 11,750 km? How miserable was our life in 2010 to fly just half of the airmiles of 2019?

jeffrey funk 15 Nov, 2021

A common-sense article that is unfortunately not so common today. We live in a world in which everything is going to change soon, and the only evidence we need is Tesla's 2% share of the U.S. auto market. AI, Big Data, VR, AR, commercial drones, smart homes, and IoT are diffusing slowly, but it will all change soon, techno-optimists say. We should be concerned about the slow diffusion of new technologies, and Vaclav Smil provides us with a great historical context. If you are interested in the market sizes of new technologies, check out these numbers: https://issues.org/science-technology-policy-economic-security-guile-tyson-wagner-forum/

Daniel Robertson 10 Nov, 2021

Echoing the previous responses this is another example of poor systems engineering.

The current aviation business is structured around liquid hydro carbon fuels. You don't achieve electric flight by waiting for energy density to approach that of jet fuel.

1: There is substantial space for increasing the energy efficiency of an aircraft. Fly slower, longer wings, distributed propulsion.

2: There is substantial space for increasing the % of the aircraft that is battery well beyond what we see in liquid fuelled aircraft. Basically we need flying batteries.

3: Said giant batteries would actually be pretty cheap by aviation standards.

4: There is no inherent reason why you need extremely long range aircraft. So long as you can get over the top of the Atlantic and Pacific Oceans you can fly routes to anywhere with a 4000km range.

5: You will need to change aircraft or charge them rapidly. With adequate focus there is no reason why door to door times would be worse than today due to our terrible hub air ports.

Can This DIY Rocket Program Send an Astronaut to Space?

Copenhagen Suborbitals is crowdfunding its crewed rocket

15 min read
Five people stand in front of two tall rockets. Some of the people are wearing space suits and holding helmets, others are holding welding equipment.

Copenhagen Suborbitals volunteers are building a crewed rocket on nights and weekends. The team includes [from left] Mads Stenfatt, Martin Hedegaard Petersen, Jørgen Skyt, Carsten Olsen, and Anna Olsen.

Mads Stenfatt

It was one of the prettiest sights I have ever seen: our homemade rocket floating down from the sky, slowed by a white-and-orange parachute that I had worked on during many nights at the dining room table. The 6.7-meter-tall Nexø II rocket was powered by a bipropellant engine designed and constructed by the Copenhagen Suborbitals team. The engine mixed ethanol and liquid oxygen together to produce a thrust of 5 kilonewtons, and the rocket soared to a height of 6,500 meters. Even more important, it came back down in one piece.

That successful mission in August 2018 was a huge step toward our goal of sending an amateur astronaut to the edge of space aboard one of our DIY rockets. We're now building the Spica rocket to fulfill that mission, and we hope to launch a crewed rocket about 10 years from now.

Copenhagen Suborbitals is the world's only crowdsourced crewed spaceflight program, funded to the tune of almost US $100,000 per year by hundreds of generous donors around the world. Our project is staffed by a motley crew of volunteers who have a wide variety of day jobs. We have plenty of engineers, as well as people like me, a pricing manager with a skydiving hobby. I'm also one of three candidates for the astronaut position.

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