Using drones for the last mile of package deliveries uses less energy and creates fewer emissions than conventional means, a new study shows.

As consumers, we’ve gotten used to the immediacy of deliveries. Order a product one day and have it at your house the next. But the logistics behind this massive movement of goods—and its environmental impact—mean that better solutions are needed to balance consumer demand and the energy consumption of “last-mile” deliveries.

To address this issue, researchers looked at what they refer to as “an increase in the demand for last-mile delivery while trying to reduce the environmental impacts of the transportation sector.”

Many companies are exploring using autonomous vehicles to perform last-mile delivery, says Thiago Rodrigues, a PhD candidate in civil and environmental engineering at Carnegie Mellon University.