Carbon footprint of robo-posties similar to human delivery

The coronavirus pandemic has driven up demand for contactless delivery, accelerating industry interest in using automation to assist delivery workers. For instance, UPS and Waymo are working together to test an autonomous delivery van in Arizona while Amazon and FedEx are among the companies experimenting with delivery drones. Meanwhile, Royal Mail has been testing use of delivery drones to reach addresses in the Isles of Scilly.

This University of Michigan study involved an examination of the environmental impacts of advanced package-delivery scenarios involving electric and petrol-powered autonomous vehicles and two-legged robots to take parcels from delivery hubs to neighbours and then to front doors. These impacts were compared with the conventional approach of a human driver hand-delivering parcels.

While robots and automation contribute less than 20 per cent of a parcel’s carbon foorprint, most of the greenhouse gas emissions originate from the vehicle itself. Vehicle powertrain and fuel economy are the key factors determining the total emissions, so switching to EVs and running them on renewables would have the biggest impact on sustainable parcel delivery, the researchers concluded.

Their study is a lifecycle analysis of the cradle-to-grave greenhouse gas emissions for 12 suburban delivery scenarios. Unlike similar studies, it does not simply tally up emissions from the delivery process; it also counts greenhouse gases from manufacturing the vehicles and robots, as well as disposing of them or recycling them at the end of their working lives.

“We found that the energy and carbon footprints of this automated parcel delivery in suburban areas was similar to that of conventional human-driven vehicles. The advantages of better fuel economy through vehicle automation were offset by greater electricity loads from automated vehicle power requirements,” said Professor Gregory Keoleian, a civil and environmental engineering expert at Michigan.  

“For all delivery systems studied, the vehicle-use phase is the single largest contributor to greenhouse gas emissions, highlighting the need for low-carbon fuels for sustainable parcel delivery. It is critically important to decarbonise grids while deploying [EVs].”

The researchers emphasised the importance of the 'last mile' - the final leg of a parcel’s journey from a delivery hub to the customer. This is the most expensive, most carbon-intensive and least energy-efficient part of the supply chain. Automated last-mile approaches have the potential to reduce overall delivery costs between 10 and 40 per cent in cities, although the researchers say their environmental impacts should be explored before they are implemented.

Keoleian added that no single automated delivery system will suit all situations, and in addition to environmental performance, other factors will need to be considered, such as life cycle costs, safety, visual impact and social sustainability factors such as employment impacts.