Journal article

Are e-scooters polluters? The environmental impacts of shared dockless electric scooters

02 Aug 2019
Description

Abstract:
Shared stand-up electric scooters are now offered in many cities as an option for short-term rental, and marketed for short-distance travel. Using life cycle assessment, the authors quantify the total environmental impacts of this mobility option associated with global warming, acidification, eutrophication, and respiratory impacts. The authors find that environmental burdens associated with charging the e-scooter are small relative to materials and manufacturing burdens of the e-scooters and the impacts associated with transporting the scooters to overnight charging stations. The results of a Monte Carlo analysis show an average value of life cycle global warming impacts of 202 g CO2-eq/passenger-mile, driven by materials and manufacturing (50%), followed by daily collection for charging (43% of impact). The authors illustrate the potential to reduce life cycle global warming impacts through improved scooter collection and charging approaches, including the use of fuel-efficient vehicles for collection (yielding 177 g CO2-eq/passenger-mile), limiting scooter collection to those with a low battery state of charge (164 g CO2-eq/passenger-mile), and reducing the driving distance per scooter for e-scooter collection and distribution (147 g CO2-eq/passenger-mile). The results prove to be highly sensitive to e-scooter lifetime; ensuring that the shared e-scooters are used for two years decreases the average life cycle emissions to 141 g CO2-eq/passenger-mile. Under the authors' Base Case assumptions, the authors find that the life cycle greenhouse gas emissions associated with e-scooter use is higher in 65% of the Monte Carlo simulations than the suite of modes of transportation that are displaced. This likelihood drops to 35%–50% under the authors' improved and efficient e-scooter collection processes and only 4% when the authors assume two-year e-scooter lifetimes. When e-scooter usage replaces average personal automobile travel, the authors nearly universally realize a net reduction in environmental impacts.

Identifiers: 
doi: 
10.1088/1748-9326/ab2da8
Volume: 
14
Access Rights Type: 
Open
License Type: 
CC BY
Language: 
English
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