The journal Nature has featured details of a study “comparing the environmental impact of various ‘last-mile’ delivery methods —which take a package on the final leg of its journey — which finds that greenhouse-gas emissions per parcel were 84% lower for drones than for diesel trucks. Drones also consumed up to 94% less energy per parcel than did the trucks. The research, published on 5 August in the journal Patterns, indicates that using drones to deliver medication and other small items could cut the environmental impact of product deliveries.”
In its feature Nature highlights that “in the United States, freight transportation accounts for more than one-third of transportation-related greenhouse-gas emissions”.
“With technology improving, drone delivery is likely to become more common in the near future” says Juan Zhang, a transportation researcher at the University of Wisconsin–Eau Claire. “Therefore, we need more studies about the energy consumption of drones,” she says.
The feature continues, “Rodrigues and his colleagues have done just such a study. The team attached packages weighing 0.5 kilograms or less to ‘quadcopter’ drones, which have four rotors, and flew them at speeds of 4–12 metres per second. 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.
“The results show that a drone’s environmental footprint depends, in part, on where it’s charged. In the US Midwest, for example, electricity generation is more carbon intensive than in New York. But regardless of region, drones have a much smaller environmental impact than do diesel and electric trucks when it comes to moving small packages: drones’ greenhouse-gas emissions per kilometre are roughly 2% of those of a medium-duty truck powered by either diesel fuel or electricity. The study also found that electric bikes consumed less energy per package than drones did.
“Using drones to deliver lightweight parcels and other electric vehicles to move larger items could slash the sector’s energy, costs says Rodrigues. But many caveats remain. For instance, most drones carry only one package at a time, so they could be less energy efficient at delivering many packages than a single truck, says Zhang. But even with this uncertainty, it’s helpful to have data that compare the energy use of drones with that of other methods of delivery, she says.”
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