NC State Study Examines Hidden Environmental Impact of Electric Scooters

Aug 6, 2019

One of these transit options might not be as green as it looks.
Credit Elizabeth Friend / WUNC

Electric scooters are touted by companies as a greener way to get around, but new research from North Carolina State University suggests they have a larger carbon footprint than many users might realize.

The study looked at the full lifecycle of how e-scooters are produced, distributed and recharged. Researchers found the manufacturing and distribution process contributed significantly to the emissions profile of the dockless scooters.

“There are environmental impacts that are, in fact, hidden,” said Jeremiah Johnson, one of the study’s co-authors. “About half of the environmental impacts are from the materials in the manufacturing, so getting the aluminum for the frame, getting that lithium-ion battery. We also saw that a large share of the burdens are from the collection and re-distribution process.” 

E-scooters don’t produce emissions when riders use them, but they are collected and recharged by independent contractors, mostly using gas-power vehicles to drive around town.

Johnson said scooter companies can improve their environmental impact by streamlining this collection process and investing in longer-lasting scooters. Many scooters in use now won't last more than a year or two, and some are out of commission in just a few months.

“If you can extend the life of the scooter, those burdens associated with the materials and the manufacturing are used over more miles, so the per-mile impact looks a lot lower,” he said.

Researchers found that while riding a scooter may be more environmentally friendly than driving a car, other transit options including riding a bike, walking, or taking the bus are likely to produce fewer emissions overall.

In a a survey of users in Raleigh, scooters only replaced car trips in a third of instances. In the majority of cases, they replaced greener modes of transit.

“If you’re displacing a car ride, the scooters look good, they have about half the CO2 emissions on a life cycle basis verses and average auto ride,” said Johnson. “But when only one third of the riders are displacing cars, that’s when the whole system impacts look a little bit less favorable.”

He said cities can help maximize the efficiency of scooters by allowing them to remain out overnight if they don’t need to be recharged, so fewer car trips are needed to transport them.

The research was published in August in the journal Environmental Research Letters.