Drones that fly packages straight to people’s doors could be an environmentally friendly alternative to conventional modes of transportation, writes Freda Kreier at Nature.
Citing research published in the journal Patterns on August 5, 2022, Kreier found that for "last mile" delivery methods—which bring packages on their final journeys to our doors—greenhouse-gas emissions per parcel were 84 percent lower for drones than for diesel trucks. Drones also consumed up to 94 percent less energy per parcel than did the trucks.
This is big news, because freight transportation accounts for more than one-third of transportation-related greenhouse-gas emissions in the USA. Not surprisingly, companies such as Amazon have been experimenting with using drones and robots to deliver packages with an eye to reducing their environmental impact.
Interest in drone deliveries grew even more during COVID-19. A survey conducted in mid-2020 found that more than 60 percent of people would be willing to pay extra for their packages to be delivered by robots.
"This was partly the result of a desire to avoid infection," says Thiago Rodrigues, a transportation researcher at Carnegie Mellon University in Pittsburgh, Pennsylvania, and a co-author of the new study. "But another incentive was the fact that automated delivery is often faster than waiting for delivery trucks to make their rounds."
Rodrigues and his colleagues have done an energy-consumption study of drones. The team attached packages weighing 1 lb or less to quadcopter drones and flew them at speeds of 9 mph to 26 mph. From these flights, the researchers were able to determine how much energy was needed to fly a drone, as well as the quantities of greenhouse gases emitted by generating the electricity to charge the drone’s battery.
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The results show that a drone’s environmental footprint depends, in part, on where it’s charged. For example, in the U.S. Midwest electricity generation is more carbon intensive than in New York. Yet regardless of region, drones have a much smaller environmental impact than do diesel and electric trucks when it comes to moving small packages. A drone's greenhouse-gas emissions per 1/2 mile are roughly two percent of those of a medium-duty truck powered by either diesel fuel or electricity.
Strangely, the study also found that electric bikes consumed less energy per package than drones.
"Using drones to deliver lightweight parcels and other electric vehicles to move larger items could slash the sector’s energy costs," says Rodrigues. “The way we deliver goods to customers is changing rapidly. Our research suggests that shifting to autonomous vehicles could provide a very efficient and sustainable approach for last-mile delivery.”