Last-mile delivery by a small drone takes much less energy per package than delivery by diesel truck
A study comparing the environmental impact of various 'last-mile' delivery methods - which take a package on the final leg of its journey - 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.
Major companies such as Amazon have been experimenting with using drones and robots to deliver packages with an eye to reducing their environmental impact.
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.
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.
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.
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.