Even under the best of circumstances, the early fleet only lasted a few months. With an aluminum frame and lithium-ion battery, replacing them means emitting more carbon. “Amortizing lithium-ion batteries plus manufacturing emissions over 200 instead of 2,000 doesn’t look good,” Matute said.
Then there’s the scooter’s own transport needs. They have traditionally relied on small batteries that need to be recharged frequently, often by hired people to pick up the scooters, drive them out of town to recharge, and then drop them off the next morning. Drivers are also used to reallocate fleets when too many scooters are left in an area where they won’t actually be used.
Combine these manufacturing and operational emissions and you account for the majority of the environmental impact of a rental program. Researchers in the North Carolina study calculated that 93 percent of the carbon footprint of shared e-scooters falls into these categories. (Charging rental e-scooters accounts for only 5% of their total emissions.)
But it means operators can reduce emissions from their leasing programmes in obvious ways: for example, by adopting novel methods for collecting and distributing their fleets. In a follow-up to the Paris study, one of the researchers, Anne de Bortoli, found that by using electric vehicles to transport e-scooters and optimize routes, operators could reduce carbon emissions by up to 55 percent. E-scooter operators are encouraged to make these changes by city officials, who are beginning to place greater emphasis on green credentials and life cycle analysis when deciding whether to grant permits.
Companies are also making their scooters more durable. Between 60% and 70% of scooter operators, including European giants like Tier and Bolt, source their scooters from Segway-Ninebot or Okai, both of which are committed to designing more robust products. Even Okai’s basic model, the electric scooter of choice for cash-strapped operators, is expected to last about two years. “Everything that is short-lived is removed from our portfolio,” said Tony Günther, head of e-commerce at Okai.
Some operators — namely Superpedestrian, Lime and Bird — go a step further by designing industrial-grade models in-house. Lime’s head of sustainability, Andrew Savage, said everything about today’s scooters is “designed for shared use”. The company’s newest electric scooters are expected to cover about 20,000 kilometers in at least five years, but more is likely. Bird expects its equivalent, the so-called three, to cover at least 10,000 kilometers in the same time frame.
Other companies such as Voi and Lime are also introducing replaceable batteries. They’re just moving the battery, not lugging the scooter to charge, and the battery also has a larger capacity, reducing the number of trips needed to keep the fleet powered. “You can take a Bird 3 and launch it in a nice city like Los Angeles, and you probably won’t need to visit that scooter again in seven or even 10 days,” Rushforth said. (Bird’s first in-house model, Zero, Usually three.)
But for now, the ecological credentials of most e-scooter rental programs are vague. While operators have flagged recent improvements, they remain cautious about disclosing how the scooters are made, their current life cycle and how they are collected, charged and distributed. On the other hand, with the e-scooter rental market growing so fast, it is difficult to extrapolate the conclusions of existing research to determine how green these projects will be in the future. (In the North Carolina study, for example, the team disassembled and analyzed the Xiaomi M365, which has long been considered unsuitable for use.) “A year, two, or three years ago research was the ancient history of this industry,” Savage said.
It’s clear that the industry is growing rapidly, and rental emissions from e-scooters will improve over time. The bigger unknown is whether we can improve the transport methods they replace. For example, in major cities such as Paris, New York and London, where efficient public transport is available, e-scooters will struggle to be the greenest way to travel. According to Lake, who participated in the Zurich study, e-scooters are often found in high-traffic city centers. But these areas are already served by public transport.
“The problem we’re facing at the moment is that there are no e-scooter companies in the suburbs because it doesn’t make sense financially,” he said. But by getting rental e-scooters into places where they’re more likely to replace gasoline and diesel-fueled cars, they can finally deliver on their early environmental promises.
Update 7/7/2022 6:15pm ET: This story has been corrected to say that the Voi is using the replaceable battery, not the Bird.