The Solar Impulse 2 concluded its journey Monday, becoming the first aircraft to circumnavigate the globe without a drop of liquid fuel. And while we won’t be boarding sun-powered commuter flights anytime soon, the solar plane’s feat does point toward the future of energy.
Pilots Bertrand Piccard and André Borschberg made the trip during 17 months, stopping in 17 cities. Sun power propelled them across approximately 26,718 miles (43,000 kilometers). Their landing in Abu Dhabi happened one day after the birthday of Amelia Earhart, who became the first woman to fly alone across the Atlantic in 1932.
The Solar Impulse assembled a number of technically advanced components in a way that wouldn’t have been possible years ago, says Craig Steeves, associate director of the University of Toronto Institute for Aerospace Studies.
That said, solar-powered commercial air travel at the capacity and speeds we expect isn’t feasible, “certainly not in my lifetime,” Steeves says. Solar Impulse can only carry one person—the pilot—and travels at about the speed of a car, 46 miles per hour (75 kilometers per hour) on average. (Learn about the secrets of the flights.)
“A lot of what they’re demonstrating,” Steeves says, “is probably going to be relevant to earth-bound applications before it becomes important to flight.”
Indeed, the plane’s lightweight materials and other components could be used on the road and the power grid. Its super-efficient engine ran on electricity generated from 17,248 solar cells. Special, energy-dense batteries stored sun power so the plane could fly at night.
Masdar, the sustainability testing ground located in Solar Impulse’s beginning and ending destination, also supported the journey. “In Abu Dhabi, you can feel the excitement surrounding Solar Impulse,” says Masdar CEO Mohamed Jameel Al Ramahi. “Being the host city is a source of tremendous national pride.”
Between the envelope-pushing advancements boasted on the Solar Impulse and the most advanced commercial planes going into service today, he says, “definitely you are seeing an overlap.”