LISBON, PORTUGAL – JANUARY 13: A number of Lime-S e-scooters are parked in a neat row outside MAAT … [+]
Corbis via Getty Images
Are shared e-scooters good or bad for cities and the climate? Do they reduce congestion and pollution, or not? In figuring out which side of the argument to take, the public, cities, and the media often miss the broader point—the answer is largely up to us. With the right supporting action by cities, these small-wheeled electric vehicles can provide more convenient, enjoyable, and efficient ways of making short trips, reclaim public space for bikes, and increase the value and use of public transit. To achieve these gains, and more, it will be up to all of us to better understand the factors and levers to unlock the benefits of e-scooters.
In this article we explore the climate impact of e-scooters, which is related to the interaction of four factors: (1) the amount of energy required to propel each shared scooter and the carbon-intensity of producing that energy, (2) the ways in which scooters are collected, recharged, and distributed across the service area, (3) the emissions from manufacturing the scooters, and (4) how shared scooters integrate into the existing mobility ecosystem. Each factor, further described below, individually and collectively shapes the environmental impact and benefits.
Factor 1: Electric motors are over three times more efficient than combustion engines and moving a person on a 30-50 lb. e-scooter takes a fraction of the energy compared to a 3,000-4,000 lb. car or SUV. One study estimates that scooters are more than 1,000% more efficient per mile than the average combustion vehicle based on the energy needed to move them. Even if e-scooters’ batteries are powered by a grid that relies on fossil fuels, the emissions per mile from the electricity generation is negligible.
Factor 2: The way e-scooters are handled for charging and redistributed to balance the coverage area can be a much larger factor determining the emissions they create. If they are picked up one by one in a diesel truck, emissions can be significant. Fortunately, improving the efficiency of pick-up, recharge, and distribution is in financial self-interest of the companies. This is why we’re seeing new innovations including the use of cargo bikes, electric vehicles, and even scooters with swappable batteries, since it’s cheaper and less emissions-intensive to replace a battery than to pick up and charge an e-scooter each time it runs low on juice.
Factor 3: Early on, the manufacturing of e-scooter devices has gotten a lot of heat. In less than two years, the shared e-scooter market graduated from using cheap personal-use e-scooters, to e-scooters optimized for sharing, with greater durability and efficiency. This is one of the fastest evolving transportation segments today and determining the overall environmental impact can be complicated. In the early days, shared e-scooters would break down after 1-2 months of use, which required frequent replacement and the associated problems of disposal. Recognizing this issue, operators quickly moved to e-scooters designed for the use and abuse of a shared system. While making e-scooters more durable can increase their individual manufacturing emissions (producing durable products often requires more material and energy), this is usually more than offset by the fact that better product durability enables longer lifetimes and more trips before disposal or recycling.
Factor 4: Another important factor is the ways scooters are used and what they substitute for, or compliment, in the mobility marketplace. In cities such as Portland, Denver, and San Francisco, researchers are finding that roughly 36% of e-scooter trips are replacing a walking trip, 10% are replacing a biking trip, 10% are replacing a public transit trip, and at least 36% are replacing an automotive vehicle trip (including private automobiles and ride-sharing). More recently, Santa Monica, the home of the first shared scooter experiment, reported that 49% of e-scooter trips replaced car trips. While the data is limited, it appears that scooters are replacing multiple modes of transportation as well as providing mobility for new trips.
October 8, 2019, Berlin: An E-scooter drives past the Federal Ministry of Transport on the cycle … [+]
dpa/picture alliance via Getty Images
A recent comprehensive analysis by the International Transport Forum that considers Factors 1 and 2 and is based on a one-year lifetime for e-scooters (Factor 3) estimates the total greenhouse gas emissions per mile for e-scooters at a combined 62 grams of carbon dioxide per kilometer. This is similar to high-occupancy public transit modes, and much better than the estimated 180-230 grams of carbon dioxide per kilometer for a gasoline-powered car. As companies continue to refine their product and operations (Factors 1-3) and scooters replace more car trips (Factor 4), the potential for emissions benefits grow.
Finally, there is one more factor that is difficult to quantify but may turn out to be the most important: the value of providing millions of people, many for the first time, the experience of traveling through a city on a small two-wheeled device. By experiencing a city from this vantage point, one becomes acutely aware of the allocation and value of public space for all transportation modes (cars, bikes, transit, pedestrians, and scooters) and the too-often inefficient allocation in favor of the most polluting, space-consuming modes. If even a fraction of micromobility users are motivated to advocate to their local government officials a reallocation of public space toward protected bike and scooter lanes, wider sidewalks, and better transit, the benefits for congestion, health, and livability could be significant.
In the last two years, shared e-scooters have evolved and steadily improved their environmental impact. But shared micromobility providers alone won’t be able to unlock full benefits. It will be up to city officials, and all of us, to support the change that we want to see on our streets.
With acknowledgement and special thanks to Lina Fedirko, Senior Program Associate at ClimateWorks, who contributed to this article.