The December 2022 issue of IEEE Spectrum is here!

Close bar

Getting Zero-Carbon Emissions Will Be Tougher For Airliners Than For Cars

Batteries are way too weak, and it’s easier said than done to turn vegetable oil into a kerosene substitute

3 min read
Getting Zero-Carbon Emissions Will Be Tougher For Airliners Than For Cars
Illustration: Chad Hagen

Eliminating kerosene-based jet fuel will be one of the greatest challenges to creating a world without carbon emissions. Aviation accounts for only about 2 percent of the global volume of such emissions and some 12 percent of the total released by the transportation sector, but converting to electric drive is much harder for airplanes than for cars and trains.

Today’s jet fuel—the most common formulation is called Jet A-1—has a number of advantages [pdf]. It packs 42.8 megajoules into each kilogram, it can stay liquid down to –47 °C, and it beats gasoline on cost, evaporative losses at high altitude, and risk of fire during handling. No real rivals yet exist. Batteries capacious enough for intercontinental flights carrying hundreds of people are still the stuff of science fiction, and we will not see wide-bodied planes fueled by liquid hydrogen anytime soon.

Keep Reading ↓Show less

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions

Economics Drives Ray-Gun Resurgence

Laser weapons, cheaper by the shot, should work well against drones and cruise missiles

4 min read
In an artist’s rendering, a truck is shown with five sets of wheels—two sets for the cab, the rest for the trailer—and a box on the top of the trailer, from which a red ray is projected on an angle, upward, ending in the silhouette of an airplane, which is being destroyed

Lockheed Martin's laser packs up to 300 kilowatts—enough to fry a drone or a plane.

Lockheed Martin

The technical challenge of missile defense has been compared with that of hitting a bullet with a bullet. Then there is the still tougher economic challenge of using an expensive interceptor to kill a cheaper target—like hitting a lead bullet with a golden one.

Maybe trouble and money could be saved by shooting down such targets with a laser. Once the system was designed, built, and paid for, the cost per shot would be low. Such considerations led planners at the Pentagon to seek a solution from Lockheed Martin, which has just delivered a 300-kilowatt laser to the U.S. Army. The new weapon combines the output of a large bundle of fiber lasers of varying frequencies to form a single beam of white light. This laser has been undergoing tests in the lab, and it should see its first field trials sometime in 2023. General Atomics, a military contractor in San Diego, is also developing a laser of this power for the Army based on what’s known as the distributed-gain design, which has a single aperture.

Keep Reading ↓Show less