Graphical Abstract. Credit: environmental science and technology (2023). DOI: 10.1021/acs.est.2c07030
Ride-hailing services Uber and Lyft have both pledged to completely electrify their vehicle fleets in the United States by 2030.
The move would eliminate tailpipe pollution while shifting emissions to power plants that provide electricity for charging EV batteries, resulting in a significant drop in overall emissions of climate-warming greenhouse gases.
Good news all around, isn’t it? Catch.
A new study by researchers at the University of Michigan and Carnegie Mellon University estimates that the overall benefit of switching ride-hailing vehicles from gasoline to electric would be very modest—on average, a 3% gain per trip when other “costs to society” are included.
Those social costs include traffic congestion, collision risk and noise caused by Uber and Lyft drivers commuting to and from fast charging stations, according to the study published online in the journal. environmental science and technology,
“Our simulations showed that electric vehicles travel a longer distance without a passenger than gasoline vehicles because EVs have to make more frequent trips to the charger than gasoline vehicles to refuel,” said study senior author Partha Vaishnav. Said, who is an assistant professor in UM’s School for the Environment and Science. sustainability.
“Also, fast chargers are not as ubiquitous as gas stations, which means that EVs have to travel further than petrol vehicles each time they refuel.”
In their simulation, the researchers used a new high-resolution model called AgentX with real-world Uber and Lyft trip data collected in the Chicago area from 2019 to 2022. Chicago is one of the largest ride-hailing markets in the country, and before the COVID-19 pandemic the number of daily trips averaged about 300,000.
The researchers modeled over a million Uber and Lyft trips taken on weekdays, weekends and during different seasons. They included trips made before the pandemic began, as well as those made during the period following the widespread rollout of vaccines.
A set of standard economic tools were used to express costs to society in dollar terms. Although the study’s results are specific to Chicago, the findings are applicable more broadly, according to the researchers.
The study found that:
- Electrification of Chicago’s ride-hailing fleet would reduce lifetime greenhouse gas emissions by 40%-45% compared to gasoline-powered vehicles. The shortfall is largely due to the greater efficiency of electric vehicles.
- Health impacts from local air pollution will increase by an average of 6%-11% per trip due to higher concentrations of local pollutants (such as sulfur dioxide, nitrogen oxides and particulate matter) from power plants burning fossil fuels.
- Additional driving to and from charging stations would increase traffic-related harm to society (congestion, accident risk and noise) by 2%-3% per trip.
- Overall, the complete electrification of ride-hailing would reduce the overall loss to society by approximately 3% per trip.
- A 3% reduction in cost to society translates to savings of approximately $1.5 million per year for the City of Chicago. To put that number in context, ride-hailing is estimated to generate $4 million to $5 million in revenue per day in Chicago.
“It may seem counterintuitive that the total cost to society turns out to be so low, even though greenhouse gas emissions are significantly reduced by switching to EVs,” said Anirudh Mohan, lead author of the study. at Princeton University.
“But on a per-mile basis, greenhouse gas emissions are a very small part of the total cost imposed on society by these vehicles. The cost is influenced by traffic externalities—congestion, crash risk and noise—which are directly related to vehicle distance.” Travelled. And with electrification the distance covered by the vehicle will increase.”
According to the study, about 80% of the total cost to society is due to traffic-related factors, while 20% is due to emissions.
The assessment ranges from abysmal to severe costs to society for manufacturing, operating and disposing of EV and gasoline-powered vehicles. Those lifetime costs include battery manufacturing, gasoline refining and vehicle manufacturing.
For EVs, the researchers looked at battery size and how it affects vehicle performance. Making smaller battery packs requires less energy and leads to lighter vehicles, both of which can lead to greenhouse gas emissions savings.
To his surprise, the smaller battery pack didn’t help. A smaller battery pack means EV drivers visit chargers more often, and those extra miles cancel out the emissions benefit from using a smaller battery pack, according to the study.
“Overall, our findings make it clear that a substantial portion of the harm caused by cars is not related to their air emissions and is therefore unlikely to be eliminated by electrification,” Vaishnav said.
“Electrification is a small victory for society. Dramatically reducing our reliance on cars would be a major victory. Policies that reduce vehicle distances through investment in public transport and infrastructure for biking and walking are critical, or that reduce accident risk through improved vehicle safety.”
more information:
Anirudh Mohan et al, Life Cycle Air Pollution, Greenhouse Gases, and Traffic Externalities Benefits and Costs of Electrifying Uber and Lyft, environmental science and technology (2023). DOI: 10.1021/acs.est.2c07030
Citation: Full electrification of Uber and Lyft vehicles would provide only modest benefits to society, study shows (2023, 7 June) Retrieved 7 June 2023
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