Contactless delivery systems boomed during the COVID-19 pandemic since they reduced the risk of transmission when delivering essential supplies like food and medications. Countries like Rwanda and Ghana used drones throughout the pandemic to limit physical contact while delivering medical commodities and COVID-19 supplies to people’s doorsteps.

In the US, companies are also adopting drone delivery services. Drones can help businesses expand their consumer reach, reduce delivery times, and increase revenues. For instance, major retail and pharmacy chains Walmart and Walgreens have partnered with DroneUp and Google’s Wing, respectively, for commercial drone delivery operations.

There’s no doubt that drone deliveries are beneficial for consumers and retailers alike, but new research shows that there’s another upside to them. As it turns out, using drones for small parcels may be more environmentally friendly than a conventional delivery truck or van.

Drones can be greener than vans and trucks for small deliveries

The use of drones for last-mile deliveries—which refers to the final step of the delivery process where the parcel arrives at the customer’s doorstep—may be an effective tool to reduce carbon emissions related to transportation. According to a recent study published in Cell Patterns, using quadcopter drones to deliver small, lightweight packages could reduce energy consumption and greenhouse gas (GHG) emissions by up to 94 and 84 percent, respectively, per package delivered.

To determine the energy consumption of a small drone, the authors developed an energy model based on 188 drone-delivery flights and found that it consumes approximately 0.08 megajoules of energy per kilometer. Afterward, they compared it to the energy consumption and associated carbon emissions of different delivery vehicles, which include diesel vans and trucks, electric vans and trucks, and electric cargo bicycles.

[Related: FedEx is charging up its electric vehicle fleet.]

Based on the study’s findings, only the electric cargo bicycles had a similar or lower carbon footprint per package than the small quadcopter drones. “Our study shows that drones could considerably reduce the energy consumption and GHG emissions of last-mile delivery, helping to mitigate the environmental footprint of the transportation sector,” says Thiago A. Rodrigues, study author and PhD candidate in the Department of Civil and Environmental Engineering at Carnegie Mellon University.

Using energy-efficient vehicles is an important first step for businesses that intend to reduce the carbon emissions of their deliveries, in addition to finding routes where more packages are delivered per mile, he adds.

Earlier this year, the US Postal Service announced that it placed an order for 50,000 Next Generation Delivery Vehicles to replace its fleet of aging delivery trucks. They intended to purchase at least 10,019 battery electric vehicles (BEV), but after facing several lawsuits for their plan to buy mostly gas-powered delivery vehicles, they increased the number of BEVs to 25,000.

Drones can produce even fewer carbon emissions if charged using renewable resources, says Sarah Lyon-Hill, associate director for research development at Virginia Tech Center for Economic and Community Engagement who was not involved in the study. Over time, the carbon emissions of electricity-powered vehicles—drones, vans, trucks, and cargo bicycles—are expected to improve as the electricity grid continues to get cleaner. And we’ll still need trucks and vans for our bigger deliveries, so greening our electricity use is still crucial.

Consumers benefit from drone deliveries

Our transportation infrastructure is currently strained due to the high demand for delivery services, which increased exponentially during the COVID-19 pandemic, says Lyon-Hill. However, even before COVID, plenty of households with needs for home delivery, such as those with elderly residents or lower-income households without car access, had limited transportation options. 

“Delivery drones have the potential to address this higher level of demand, decrease road congestion, speed up last-mile delivery services, and offer those services at lower costs to support lower-income households,” says Lyon-Hill. By reducing the number of vans on the road, drone deliveries can reduce traffic congestion, noise pollution, and harmful emissions. 

Drones may also be an effective way to deliver urgent medications and medical supplies, especially in rural areas. In a 2021 European Heart Journal study, drones with automated external defibrillators (AED) were deployed for 12 cases of out-of-hospital cardiac arrest. The AED was successfully delivered onsite in 92 percent of the cases and arrived before the ambulance in 64 percent of the cases.

[Related: Check out Wing’s new delivery drone prototypes.]

Despite the benefits of drones, there are still limitations that might prevent their use in certain applications. For instance, drones have limited capacity in terms of the mass and volume of the parcel they can transport, says Rodrigues. He adds that some areas may also be subjected to aerospace regulatory restrictions, which limit drone delivery routes. Areas near airports, schools, stadiums, and government buildings may have temporary and permanent no-fly zones that prohibit drone flights.

And companies are already on top of it. Amazon Prime Air, which plans to start drone deliveries this year, is currently working with the Federal Aviation Administration (FAA) and local officials in Lockeford, California to give consumers the option to have their parcels delivered via drones. 

“Other companies will likely follow this trend [of drone deliveries],” says Rodrigues, “if we develop the conditions to overcome some of the operational and regulatory challenges mentioned.”

Of course, just like with driverless cars and other forms of automation, there are always concerns with what will happen for delivery workers and their jobs. But drone deliveries, even when all of the policy kinks are straightened out, will still only be one part of future deliveries. Until then, making sustainable choices like ordering fewer times in larger quantities or accepting slower delivery times, can help bring down your online shopping footprint no matter how it is delivered.