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New Study Suggests that E-scooters Reduce Carbon Emissions

Thursday, November 10, 2022

A new study from leading German research institute Fraunhofer ISI, reveals that the latest generations of shared e-scooters and e-bikes can reduce carbon emissions within city transportation networks.

In spring 2022 researchers from Fraunhofer surveyed Lime riders across six cities globally, including Stockholm, Paris, Melbourne, Berlin, Seattle, and Dusseldorf. The riders were asked what mode they would have taken on their most recent trip if an e-scooter or e-bike were not available. This data was then fused with a lifecycle analysis of Lime’s latest Gen4 e-bikes and e-scooters, measuring the service’s carbon footprint.

The study measured whether Lime scooters replace enough high-emission cars, taxi and ride hail trips, and higher-emitting forms of public transportation to compensate for the carbon impacts of replacing walking or lower carbon transportation. The largest effects for shared e-scooters are observed in Melbourne (-42.2g/pkm) and Seattle (-37.7g/pkm). However, Seattle also has the highest share of replaced walking trips and the highest share of replaced ride-hailing trips. Berlin has the smallest emission reduction (-14.8g/pkm) and has shown relatively larger shares of personal bikes and subway replaced by shared micromobility modes. In each city, the overall result of the study is that shared e-scooters reduce more carbon emissions than shared e-bikes, and crucial to both modes’ emissions reductions potential is the potential to replace the highest-emitting modes like taxi/ride hailing and personal cars.

Interesting to note that the report found that the greatest carbon savings from mode shift occurs when riders choose e-scooters instead of taking a taxi or ride hailing service. Through Lime’s partnership with Uber, riders can book a Lime e-scooter or e-bike through the Uber app, encouraging even greater mode shift. Riders who booked Lime e-scooters via the Uber app were not surveyed in the study, making it likely that the carbon savings of Lime’s service is even greater than presented in the study.

Personal Comment:

Interestingly, the research on the carbon emission impact of micromobility has been mixed with some earlier studies suggesting that e-scooters and other micromobility modes are net-contributors to carbon emissions. For example, according to a 2019 study conducted in the US state of North Carolina, shared e-scooters produce 202g of CO2 per passenger mile over their entire lifecycle. Another study (2020) conducted in Paris concluded that the city’s shared e-scooters added 13,000 metric tons of additional greenhouse gases to the city’s carbon footprint over a year.

However, these studies used lifecycle emissions data from older generations of e-scooter hardware and operational practices. Shared micromobility companies, like Lime, have improved hardware and operational practice, such as longer-lasting scooters and electrifying the service vehicles that support the fleet. According to the most recent lifecycle analysis of Lime’s Gen4 e-scooter Lime managed to improve its lifecycle emissions, resulting in an 84% drop in CO2/passenger km travelled in just three years.

It is important that the industry continues extending vehicle lifespans by making them more durable and fully repairable. Swappable and interchangeable batteries also have a significant impact. The study also shows that partnerships with taxi or ride-hailing companies can increase mode shifts toward these more sustainable modes of transportation.

Written by Kateryna Melnyk,
RISE Mobility & Systems