A new study by researchers at North Carolina State University concluded that e-scooters have a larger environmental footprint than other forms of micro-mobility. They're greener than cars, but still have room to improve.
For all of the sustainability ethos surrounding rentable electric scooters, it turns out they may only be greener than a personal automobile.
A new study by researchers at North Carolina State University found the carbon footprint of an e-scooter, over the course of its often short life, is greater than many micro-mobility and public transit advocates may be comfortable with.
Because the scooters need to be gathered, recharged and redistributed — usually thanks to some form of fossil-fuel powered vehicle — their green bonafides are greatly reduced, the study found. The research also found that many scooters only have a 12-month to 24-month life cycle, further eating into environmental benefits once their materials and production are considered.
“What we’re trying to do is understand the full picture, including some of the hidden things, the things that may be a little less obvious,” said Jeremiah Johnson, one of the lead authors of the report. Johnson is also an associate professor of civil, construction and environmental engineering at North Carolina State University.
Researchers also took into consideration the carbon footprint of shipping the scooters to the United States from China, where they are generally produced, as well as the electricity used to recharge them. Both of these factors turned out to be negligible when studying the devices’ overall environmental impact.
“In our study, the materials and manufacturing were about half of the greenhouse gas burden,” said Johnson, adding, “and the collection and redistribution process was over 40 percent.”
In only two years, thousands of rent-to-ride electric scooters have appeared in dozens of cities. They provided some 38.5 million rides in 2018, according to the National Association of City Transportation Officials (NACTO). The scooters have stoked both the ire and glee of city and transportation officials who have struggled with haphazardly placed, or vandalized, devices. But by the same token, public policymakers have praised scooters’ ability to replace car trips, cutting down on emissions and congestion.
“In our survey we found that about one-third of the [scooter] rides were displacing car rides,” said Johnson. However, some 49 percent of respondents said they would have biked or walked, were the scooter not available, according to the report. Eleven percent said they would have taken a public bus.
“So if you’re substituting car rides, it looks great. But the challenge comes up in that half the time you’re substituting walking or biking,” he added. Both walking and biking are rated substantially greener than a ride on a scooter.
Perhaps one of the most comprehensive examinations of local scooter use was the 2018 E-Scooter Findings Report by the Portland, Ore., Bureau of Transportation. Similarly, that study found 34 percent of Portland residents used scooters to replace a car trip. And 48 percent of visitors did the same.
“We believe there is a preliminary indication that e-scooters are a less-polluting travel option,” the Portland report concludes. “However, we need more data — especially regarding e-scooter operations and lifecycle costs — before we can definitively say how much of even whether e-scooters directly contribute to a reduction in greenhouse gases.”
For its part, during Portland’s latest scooter pilot period, PBOT is offering incentives to contractors who recharge scooters, encouraging them to use low-emission vehicles, said Dylan Rivera, a spokesman for PBOT. For example, scooter operators can increase their scooter fleet by up to 35 percent if they can prove a reduction of “operational vehicle miles traveled.”
Meanwhile, scooter companies like Skip have planned to introduce next-generation devices with swappable batteries that can be changed on-the-fly, eliminating the need for devices to be loaded into a vehicle and driven to a recharging location.
Cities should explore steps to reduce driving among contractors to collect and redistribute the scooters, said Johnson. His research in Raleigh showed that roughly one out of six scooters were either fully charged or near fully charged at the end of the day.
“But they were still picked up, because they had to be removed from the city streets. And so there’s unnecessary driving to pick up a fully charged scooter, to bring it to a charging station, which it doesn’t need and then redistribute it the next day,” said Johnson.
“I recognize that there are other complications with leaving the scooters on the streets overnight. But if a solution could be found that would allow that, that would reduce some of that driving,” he added.