Considering the nuisance valuable-tough to calculate.
Sorry, scooters aren’t so climate-friendly after all
A look at the full lifetime emissions of the vehicles call into question the ecological assumptions around “micromobility.”
Bird boasts that its dockless electric scooters allow customers to “cruise past traffic and cut back on CO2 emissions—one ride at a time.”
Its rival Lime claims
the vehicles “reduce dependence on personal automobiles for short
distance transportation and leave future generations with a cleaner,
healthier planet.”
But the mere fact that battery-powered scooters don’t belch pollution out of a tailpipe doesn’t mean they’re “emissions free,” or as “eco-friendly” as some have
assumed. The actual climate impact of the vehicles depends heavily on
how they’re made, what they’re replacing, and how long they last.
Researchers
at North Carolina State University decided to conduct a “life-cycle
assessment” that tallied up the emissions from making, shipping,
charging, collecting, and disposing of scooters after one of them
noticed that a Lime receipt stated, “Your ride was carbon free.”
The study concludes that dockless scooters
generally produce more greenhouse-gas emissions per passenger mile than
a standard diesel bus with high ridership, an electric moped, an
electric bicycle, a bicycle—or, of course, a walk.
The
paper found that scooters do produce about half the emissions of a
standard automobile, at around 200 grams of carbon dioxide per mile
compared with nearly 415. But, crucially, the researchers found in a
survey of e-scooter riders in Raleigh, North Carolina, that only 34%
would have otherwise used a personal car or ride-sharing service. Nearly
half would have biked or walked, 11% would have taken the bus, and 7%
would have simply skipped the trip.
The
bottom line: roughly two-thirds of the time, scooter rides generate
more greenhouse-gas emissions than the alternative. And those increased
emissions were greater than the gains from the car rides not taken, says
Jeremiah Johnson, an engineering professor and one of the authors of
the paper.
The
electricity used to charge the vehicles is one of the smallest
contributors to the product’s emissions. Fully half come from the raw
materials and manufacturing process, which the researchers estimated, in
part, by disassembling a Chinese-made Xiaomi M365 scooter, a model that
Lime and Bird are known to use.
The
team weighed each part, including the aluminum frame, steel parts,
lithium-ion battery, and electric motor. They then relied upon the
findings of earlier peer-reviewed studies to assess the environmental
impacts of extracting, producing, and delivering those raw materials.
But
how much these emissions add up to on a per-mile basis depends heavily
on how long scooters actually last. An increasingly evident problem is
that the vehicles’ theoretical operating life of around two years
scarcely resembles their “nasty, brutish and often short” existence in the real world.
Scooters are variously flung into water bodies, tossed from buildings, set on fire, run over, and used in stunts. Cleanup crews in Oakland, California, fished 60 scooters out of Lake Merritt in a single month last year, Slate reported.
An
analysis of open data from Bird’s inaugural fleet in Louisville,
Kentucky, conducted by Quartz last year, found that the average scooter lasted just 28.8 days.
Likewise, Bird itself acknowledged in investor documents at an earlier
point that its vehicles last only about a month or two, The Information reported.
The
other major share of emissions, 43%, comes from the additional fleet of
vehicles needed to navigate around a city like Raleigh each day,
collecting scooters strewn across yards and sidewalks, taking them to a
central charging location, and returning them to spots where riders can
find to
Lime has made an effort to address some of the concerns raised about its environmental footprint.
Late last year, the company announced it would offset all the emissions
from charging its scooters and the vehicles used to pick them up by
purchasing clean electricity, and investing in renewable energy and
carbon offsets projects.
"We
welcome research into the environmental benefits of new mobility
options, however this study is largely based on assumptions and
incomplete data that produces high variability in the results," Lime
said in a statement. "We believe micromobility will reduce pollution and
mitigate climate change through clean and efficient modes of
transportation and we’re making rapid advances in technology and
operations that are helping us become a more sustainable company."
The North Carolina findings are, however, consistent with some earlier efforts to evaluate life-cycle emissions or usage patterns.
The
Portland Bureau of Transportation found that only 34% of the city’s
riders took an e-scooter instead of driving their own car, or using a
ride-sharing service or taxi. In fact, Lime itself found that about “1 out of every 3 trips” replaces a car ride, in surveys across 26 cities.
On
the other hand, an unpublished analysis for clients by the Rhodium
Group put the emissions figure far lower, at 28 grams per mile, the Financial Times reported.
Hannah Pitt, an analyst with the research firm, said the new study’s
methodology looked reasonable, but that there were some key differences
in assumptions that added up to a wide gap in the end results.
Among
them, Rhodium didn’t assume every scooter is picked up each night.
Raleigh policy requires this, but that doesn’t mean it’s the common
practice. The firm also assumed the vehicles last on the roads through
their standard battery life, which Pitt says might have been too
generous, given the level of vandalism and real-world wear and tear
that’s since become clear.
Still, she says: “It would be shocking if a scooter’s per-mile emissions is half those of a passenger vehicle.”
The
good news, according to the North Carolina study, is there are ways to
reduce the emissions, including using electric or at least more
fuel-efficient vehicles to collect the scooters, reducing the distance
between pick-up and drop-off points, and only gathering vehicles with a
low battery charge. Increasing the proportion of recycled materials,
especially the aluminum, would also help.
The
change that might matter most is extending the lives of scooters. If
the vehicles lasted for two years instead of a few months, the study
found, it would cut average emissions by about 30% per mile—and make
scooters the cleaner option as much as 96% of the time.
But no surprise: walking is still going to be your greenest bet for getting around
