It’s perhaps unsurprising that drones — assuming they’re electric-powered, as most are — are better for the environment in terms of carbon emissions than diesel or petrol-powered vehicles. But in a competition between drones vs. electric bikes and electric cars, what’s the best option for the environment?
A scientific study pitted drones vs. electric bikes and cars
A study by the University of Maynooth in Ireland sought to answer exactly that, by comparing the amount of carbon emitted during drone delivery to terrestrial forms of delivery, including cars, motorbikes and electric bikes. The study was commissioned by Manna, an Ireland-based drone delivery company, so keep that in mind in terms of any potential conflict of interest.
For the study, a variety of vehicles were assessed under three difference scenarios, broken down by duration of the trip, number of stops and physical distance. The drones analyzed in the study were those used by Manna, which uses quadcopter drones to carry out deliveries, mostly in Ireland.
Ultimately the study found that drones are a pretty clean form of delivery — though not necessarily the cleanest. In a mashup between drones vs. electric bikes, it’s actually the bikes that win in every scenario. Luckily though, drones beat out electric cars for last-mile delivery, coming in at spot number two for lowest carbon emissions.
The Maynooth study showed that Manna’s drone emitted between 6 & 8 times less C02 than a small petrol car (assuming a 1.4L engine). Here’s how each scenario broke down:
Scenario 1: C02 emitted in an hour
For the first study, each mode of transport made the same number of journeys over the same locations over the course of an hour. Given no road limitations of roads, drones were able to fly a shorter actual distance, though electric bikes still won out.
Scenario 2: Account for stops
Generally speaking, a drone can only carry one package at a time, so it’d have to make two trips even if delivering to two next door neighbors. A car could likely deliver dozens of packages in one go. To account for that, the second scenario had the ground vehicles perform six deliveries all on a single outward journey. Meanwhile, the drone and electric bike returned to the initial takeoff point between each delivery to collect all six packages.
Even still, the drones and electric bikes one out.
Scenario 3: C02 emitted in one kilometer
This scenario ignored the number of journeys, instead honing in simply on carbon emitted per kilometer. The results showed that Manna’s drone emitted approximately 6 times less C02 than a small petrol car (1.4L engine ) per kilometer, though the bike produced about 4 times less than the drone.
Why drones might still win: time
Though if time is money, here’s another case for drone delivery: the researchers noted that, although E-Bikes may emit slightly less carbon dioxide, they take twice as long as drones to complete deliveries. E-Bikes must share the road, while drones generally don’t experience a ton of traffic.
And in scenarios where bikes can only make one delivery at a time, they’re especially slow compared to cars. That was evidenced in the second scenario, where the car made six deliveries in one trip, while the e-bike returned home every time in that scenario — despite producing 16x less CO2 than the 1.4L petrol car — it took almost twice as long to complete the same six journeys, even relative to the drone. In that scenario, the bike took 49 minutes and the drone took just 28 minutes.
If it’s time you value, drones might be the winner. But given that drones need to charge and aren’t necessarily the most efficient form of flight vs. wheels on the ground, an electric bike is still a greener way to get last-mile deliveries.
And keep in mind that this study analyzed quadcopter-style drones. Other drone delivery companies have been experimenting with designs that might be more environmentally friendly. Wingcopter has an eVTOL drone, which blends the helicopter with the airplane style in an attempt to get the best of both worlds. Drone delivery giant Zipline uses fixed-wing drones, which are seen as far more efficient than copter style — which also gives hope for future studies to prove that drones might be even greener than electric bikes.
Check out the full study on drones vs. electric bikes here.