Can battery-powered airplanes decarbonize air travel?

Travelers hopping between islands or making regional jaunts could take those trips on battery-powered aircraft in the not-so-distant future. Startup manufacturers and legacy airlines alike are planning to launch the first electric commercial flights before the end of this decade. Yet even if the technology takes off as promised, battery-powered planes will play only a minuscule role in curbing climate pollution from passenger air travel, a new study says.

That’s because the vast majority of aviation’s greenhouse gas emissions come from aircraft that seat more than 100 people and fly over 1,000 miles per trip. Batteries alone can’t handle that kind of weight or distance, owing to their limited energy density. Of the more than 200 electrically propelled aircraft in development worldwide, most are smaller models meant to carry handfuls of passengers over short commutes.

As a result, electric aircraft will likely mitigate just 0.2 percent of aviation’s projected emissions in 2050, the International Council on Clean Transportation (ICCT) said in a report released on Wednesday that examines the potential role of electric aircraft in decarbonizing air travel. Other alternatives, namely ​“sustainable aviation fuels” and hydrogen, are expected to meet the bulk of aviation’s energy needs by midcentury.

The new report analyzes three types of electric aircraft that startups are currently developing — a nine-seater, a 19-seater and a 90-seater — as well as how aircraft perform with existing and more advanced battery technologies. It finds that, while these planes will be limited to short trips, they could still clean up the increasingly dirty aviation industry in other important ways.

Replacing petroleum-based jet fuel with battery power would eliminate harmful air pollution and noise disturbances at airports and in surrounding communities. Using batteries in small planes also reduces competition for the alternative fuels that are needed for larger, higher-emitting aircraft — fuels that today are in extremely scant supply. And, given that electric motors are far more energy-efficient than combustion engines, flying battery-powered planes lessens the industry’s overall demand for fuel.

“The idea is that, yes, electric aircraft don’t do much [for carbon emissions], but you still want to use them wherever you can,” said Jayant Mukhopadhaya, a Berlin-based researcher for ICCT and lead author of the new report.

Aviation accounts for about 2.8 percent of global emissions every year, and that figure is expected to climb in the coming decades as passenger travel grows.

Later this year, international regulators are poised to set a ​“long-term aspirational goal” for reducing aviation’s emissions in line with global climate targets. In the United States, the Biden administration recently adopted an action plan for achieving net-zero emissions in the domestic aviation sector by 2050, and the Federal Aviation Administration is proposing fuel-efficiency standards for new U.S.-made aircraft.

Amid mounting pressure from regulators and customers, aviation companies are working to jump-start and scale a variety of cleaner yet still-emerging technologies. Airplanes, like cargo ships, are notoriously difficult to decarbonize because they consume vast amounts of energy over long distances, and they need to store plenty of fuel on board. For wide-body jets in particular, the power levels required for takeoff are comparable to those of a nuclear reactor or a coal-fired power plant.

“This is about an all-hands approach to decarbonizing air travel,” said Mike Leskinen, president of United Airlines Ventures, the company’s venture capital arm.

Last year, United and its regional partner Mesa Air Group invested in a $35 million funding round for Heart Aerospace, a Swedish startup that’s making electric 19-seat aircraft. The airlines also agreed to buy up to 200 of the startup’s planes, the first of which are supposed to be delivered for commercial use by 2026. United is also backing ZeroAvia, which is developing a hydrogen fuel-cell aircraft, and is partnering with companies that are making liquid fuels from microbes, forest residues, discarded cooking oil and municipal solid waste.

Leskinen said he expects United will use electric aircraft on routes of up to 300 miles, which is roughly the flight distance from United’s Chicago hub to Columbus, Ohio. Legacy carriers in general have cut such regional routes in recent years because the cost of fueling and piloting conventional planes often eclipses what airlines earn from shuttling small groups of passengers.

“If you can turn that on its head by having electric-powered aircraft that are cheaper to fuel and maintain, there’s tremendous customer demand for that [segment], particularly in a lot of the hubs we fly out of,” he said, naming cities like Chicago, Houston and Denver.

Aviation manufacturers predict that around 10,000 nine-passenger planes will need to be replaced in the coming years, though that number could more than double if regional air travel expands. For context, the global fleet had about 23,700 aircraft in 2021, the bulk of which were planes serving medium- and long-haul flights.

United’s partner Heart Aerospace is among a handful of startups working with major passenger and cargo carriers to launch battery-powered planes, potentially within two to three years. U.S. commuter airline Cape Air has placed orders for a nine-seat passenger plane made by Israeli startup Eviation, while German logistics giant DHL has ordered a cargo version. Italian startup Tecnam is building an electric nine-seater, while Los Angeles–based Wright Electric is working on a 100-seat plane designed for routes one hour in duration or less.

Major engine and aircraft makers are developing electric models, including Siemens, Rolls-Royce and Airbus — the latter of which is also heavily pursuing hydrogen-powered planes for medium- and long-distance flights. In September, Rolls-Royce flew an aircraft with a 400-kilowatt electric powertrain across the U.K. skies for around 15 minutes. The company claims the tiny propeller plane is the world’s fastest all-electric aircraft, having hit top speeds of nearly 350 miles per hour.

Still more companies are pursuing another form of battery-powered aviation — a much-hyped segment known as urban air mobility, or electric vertical takeoff and landing aircraft. These tiny aircraft would essentially replace helicopter or taxi rides within cities, ferrying commuters from, say, Midtown Manhattan to LaGuardia Airport in New York City.

The ICCT researchers didn’t factor air taxis into their latest report because these novel aircraft represent new demand for flying and don’t necessarily affect predictions for more conventional passenger routes, Mukhopadhaya said.