Electric cars are all over the roads these days. But what about electric planes?
Air travel currently accounts for only about 2% of global carbon emissions. But it's expected to grow in the next century, and clean air travel is seen as a key part of slowing global warming.
"We're expecting to see massive growth," says Umair Irfan, who writes about climate change, energy and the environment for Vox. "The International Civil Aviation Organization projects upward of 700 percent growth by the middle of the century. So while it is small, it is going to be a larger and larger share."
This interview has been edited lightly for clarity and length.
You've written that we need electric airplanes. Why?
We need to be able to counteract that [growth in air travel] somehow. Electrifying air travel is one key option, particularly for shorter flights, and we're already seeing at least a couple airlines experimenting with it. [Harbour Air] in the Pacific Northwest aims to electrify its whole fleet, but it only flies routes [shorter] than 100 miles.
Right now, that's where the technology is. It can basically support small aircraft going short distances, but you absolutely need something that's going to decarbonize air travel to some extent because it is going to be a large and growing share of the problem.
Are any airlines already using them to carry passengers?
Not right now. One of the big issues is that the Federal Aviation Administration hasn't approved electric aircraft for passenger air travel. The regulations are actually a big hang-up right now because much of the rules are structured around conventional aircraft, and now they need a new set of rules to deal with battery electric aircraft. That's also going to be challenged in the coming years.
Considering where technology stands today, how far are we from having an electric airplane that could cross the Atlantic Ocean?
The key problem right now is that jet fuel is extremely energy dense and batteries are not. And in an airplane, space is at a premium and so is weight. And so you want to pack as much power into a smaller space as possible. Batteries are improving, but not fast enough right now. They need to be able to store much more energy in a much smaller space.
Some airlines are experimenting with biofuels. Is that helpful?
Biofuels are a big part of it as well. The idea is that if you use a crop that takes CO2 from the air and you burn that instead, effectively it's carbon neutral. That's a little bit tricky to pull off, though, because you want to make sure you get more energy out of the fuel than you expend to grow it in the first place.
Biofuels are also a little bit more expensive than conventional fuels. And so you have to make sort of an economic argument. Right now, airlines are experimenting with it, but it's more expensive than conventional fuels and so we need a really substantial price drop in order to make inroads.
For people who want to do something about their flight-related carbon emissions now, is buying carbon offsets really the only option?
The biggest impact option would be just to fly less, and there's a global movement that's kind of sprung up to try to encourage people to do that. I think the estimate is that each leg of a journey on a roundtrip flight across the Atlantic emits about a ton of CO2. So that's 2 tons of CO2, and that's roughly enough to melt about 30 square feet of Arctic ice. So that's a very direct relationship between your actions and your impact on the environment. And for some people that's been a pretty startling revelation.
Do you think the airlines feel the urgency to get an electric plane up in the air?
There is some pressure on the airlines right now because of a global "flying shame" movement [making people feel guilty for the carbon emissions caused by their flights] that's kind of taken off. The Swedes have even coined a word for it. They call it flygskam.
Customers are now increasing pressure on the airlines. They want to assuage their guilt for flying. Many people see it as necessary, but they want to see more heavy lifting coming from the airlines themselves in terms of getting more fuel efficient or coming up with better offsetting schemes or mitigating greenhouse gas emissions in other ways.