As a balmy spring evening descended on western Paris, I needed to make my way across town to my apartment, roughly three kilometers away. The streets were congested, so I was hesitant to take a cab, and I didn’t feel like taking the Metro because it was hot and the station was far away. So I rented a battery-powered scooter that was available on the street and nipped through traffic, right to my front door. The trip was fun, not to mention affordable and speedy. It was also green, I assumed: Escooters don’t belch out fumes, so it had to be, right?
The rollout of massive numbers of shared escooters has been built on this premise: Instead of a gas-guzzling car, take an electric two-wheeler. Save the planet and time. Lime, which operates across the world but mainly in Europe and North America, aims to “build a future where transportation is shared, affordable and carbon-free.” Another operator, Bird, suggests that users can “cut back on CO2—one ride at a time.”
But research indicates that rental escooters haven’t actually reduced carbon emissions in cities. It’s complicated, says Juan Matute, deputy director of the Institute of Transportation Studies at the University of California, Los Angeles. There are plenty of circumstances in which escooter programs can be green, he says, but it depends on how and where they’re operating.Love them or loathe them, rental escooters have flooded the world’s largest cities. People in the US took an estimated 86 million trips on shared escooters in 2019, before pandemic disruption saw nearly all forms of transport fall. Even in Covid-stricken 2020—the latest year for which there’s data—people across the US, Canada, and Mexico managed to make over 25 million trips. You can find escooter rentals in hundreds of cities on both sides of the Atlantic, including Seattle, London, Rome, and Kyiv. They’re also descending on New York, and increasingly in cities in Asia. The first of these programs was launched by the micromobility company Bird in Santa Monica, California, in September 2017. Others soon followed and were an immediate success. But as the market expanded, there was little rigorous analysis of these rental programs’ environmental impact. Escooters were assumed to have a negligible carbon footprint, which helped companies raise huge sums of investment. By May 2019, there were 14 escooter companies operating across 97 American cities.To assess the environmental impact of these programs, you must account for escooters’ emissions over their full lifecycle: the production of the materials and components that go into each scooter; the manufacturing process; the shipping of the scooters to wherever they’re going to be used; the collecting, charging, and redistributing of the scooters; and the disposing of them. Once you do that, it can paint a bleak picture.
According to a 2019 study conducted in the US state of North Carolina, shared escooters produce 202 grams of CO2 per passenger mile over their entire lifecycle—more than an electric moped (119 grams), electric bicycle (40 grams), bicycle (8 grams), and even a diesel bus (82 grams), assuming it has high ridership. Though the study found that escooters produce lower carbon emissions than a shared car (415 grams), only 34 percent of the escooter trips analyzed replaced a journey that would have been taken in one.
In contrast, nearly half the trips would have been a bike ride or a walk, and 11 percent would have been bus rides. 7 percent of the trips wouldn’t have happened at all without escooters. Because the scooters’ additional emissions were greater than any gains made from car journeys not taken, the study concluded that escooter rental programs add to transport emissions overall.These findings were compounded by a 2020 study in Paris, which concluded that the city’s shared escooters added 13,000 metric tons of additional greenhouse gases to the city’s carbon footprint over a year, equivalent to the total annual emissions of a small town. Again, escooter trips were often replacing journeys made on lower-emitting modes of transport.
Earlier this year, a study by Daniel Reck and Kay Axhausen at the Swiss Federal Institute of Technology in Zurich concluded that, on average, a shared escooter creates 51 more grams of CO2 per kilometer than the means of transport it’s replacing. “The bottom line is that shared escooters are currently damaging the climate,” Reck said in an interview with German newspaper Die Zeit.
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A large part of this comes down to poor design. During the early days of escooter rentals, the industry deployed lightly modified versions of models sold directly to consumers. Manufactured in China by companies like Xiaomi and Segway-Ninebot, they weren’t prepared for the rigors of the sharing economy. The battery casing often wasn’t even waterproof, so in wetter places batteries would ignite, and there was no protection against vandalism and theft. Where scooters were a novelty, they’d often be destroyed. “The first round of vehicles weren’t really designed for this industry,” says Scott Rushforth, chief vehicle officer for Bird.
Early fleets lasted just a few months, even in the best cases. And with their aluminum frames and lithium-ion batteries, replacing them meant emitting a lot more carbon. “Amortizing lithium-ion batteries plus the manufacturing emissions over 200 trips rather than 2,000 trips doesn’t look good,” Matute says.
Then there’s the scooters’ own transport needs. They’ve traditionally relied on small batteries that need to be charged often, normally by people hired to pick the scooters up, drive them out of town for charging, and drop them off the following morning. Drivers are also used to redistribute the fleet when too many scooters are left in an area where they’re not realistically going to be used.
Combine these manufacturing and operational emissions and you account for the bulk of a rental program’s environmental impact. The researchers of the North Carolina study calculated that 93 percent of a shared escooter’s carbon footprint falls into these categories. (Charging a rental escooter accounts for just 5 percent of its overall emissions.)
But this means that there are obvious ways that operators can reduce the emissions of their rental programs: for instance, with novel approaches to collecting and distributing their fleet. In a follow-up to the Paris study, one of its researchers, Anne de Bortoli, found that by transporting escooters in electric vehicles and optimizing routes, operators could reduce carbon emissions by as much as 55 percent. Escooter operators have been encouraged to make these changes by city officials, who’ve started to place more emphasis on green credentials and lifecycle analysis when deciding whether to grant a license. Companies are also making their scooters longer lasting. Between 60 and 70 percent of escooter operators—including European giants like Tier and Bolt—source their scooters from either Segway-Ninebot or Okai, and both companies have worked to design more robust and durable products. Even Okai’s basic model, the choice of escooter for cash-strapped operators, is expected to last around two years. “Everything with a short lifespan was cut out of our portfolio,” says Tony Günther, Okai’s head of ecommerce.
Some operators—namely Superpedestrian, Lime, and Bird—have gone a step further by designing industry-grade models in-house. Everything about today’s scooters are “built for shared-use longevity,” says Andrew Savage, head of sustainability at Lime. The company’s latest escooter is expected to cover around 20,000 kilometers over at least five years, but there’s a possibility that it’ll be more. Bird expects its equivalent, known as the Three, to cover a minimum of 10,000 kilometers over the same time frame.
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Other companies, such as Voi and Lime, are also introducing swappable batteries. Instead of lugging around scooters for recharging they’re just moving batteries, which also have bigger capacity, reducing the number of trips required to keep their fleets powered. “You can take a Bird Three and launch it in a good city, like Los Angeles,” says Rushforth, “and you probably don’t need to visit that scooter again for seven or even 10 days.” (Bird’s first in-house model, the Zero, would typically go three.)But as it stands, the ecocredentials of most escooter rental programs are foggy. Despite recent improvements that operators have flagged, they’re still cagey about disclosing how scooters are manufactured, what their current life cycles are, and how they’re collected, charged, and distributed. On the other hand, because the escooter rental market has been evolving so quickly, it’s hard to extrapolate the conclusions of existing research to determine how green these programs will be in the future. (In the North Carolina study, for example, the team took apart and analyzed a Xiaomi M365, which has long been deemed unfit for purpose.) “A study of one year ago, two years ago, or three years ago is ancient history in this industry,” says Savage.
It’s clear that the industry is developing rapidly and that escooter rental emissions will improve over time. A bigger unknown is whether we can improve the transport methods that they replace. In major cities like Paris, New York, and London, for example, where there’s efficient public transport, escooters are going to struggle to be the greenest way of getting around. According to Reck, who worked on the Zurich study, escooters are often present in city centers, where there’s high footfall. But these are areas already well served by public transport.
“At the moment we have the problem that escooter companies are not present in the outskirts, because it doesn’t make sense economically,” he says. But get rental escooters into places where they’re more likely to displace petrol and diesel fueled cars, and they could finally live up to their early ecopromise.
Updated 7-7-2022 6:15 pm ET: This story was corrected to state that Voi, not Bird, is using swappable batteries.