Fleet of automated electric taxis could deliver environmental and energy benefits

Fleet of automated electric taxis could deliver environmental and energy benefits
Berkeley Lab and UC Berkeley researchers developed a model to analyze taxi trips provided by shared automated electric vehicles in Manhattan; blue represents an empty vehicle, green is charging, and red is occupied. Credit: Berkeley Lab

It may be only a matter of time before urban dwellers can hail a self-driving taxi, so researchers at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley decided to analyze the cost, energy, and environmental implications of a fleet of self-driving electric vehicles operating in Manhattan.

Using models they built and data from more than 10 million trips in New York City, they found that shared automated electric vehicles, or SAEVs, could get the job done at a lower cost - by an order of magnitude - than present-day taxis while also reducing and energy consumption. What's more, they found that "range anxiety" is moot because smaller cars with a smaller battery range were sufficient to complete the trips, although more charging stations would be needed.

Their study, "Cost, Energy, and Environmental Impact of Automated Electric Taxi Fleets in Manhattan," was published recently in the journal Environmental Science & Technology. The corresponding author is Gordon Bauer of UC Berkeley's Energy and Resources Group, and co-authors are Jeffery Greenblatt and Brian Gerke of Berkeley Lab.

"The EV industry is focusing on the personal car market, trying to make the range as large as possible," said Greenblatt. "The standard now is 200 miles. We suspected you wouldn't need as much for taxis. We found plenty of times during the day when a portion of taxis could slip off to recharge, even if just for a few minutes. This greatly reduces the need to have a big battery and therefore drives down cost. It is dependent on having a fairly dense charging network."

The researchers developed an agent-based model to simulate the movement of 7,000 taxis around Manhattan throughout the day. They also built models to analyze the cost of service and optimal placement of vehicle chargers. They found that would be lowest with a battery range of 50 to 90 miles, and with either 66 slower Level 2 chargers per square mile or 44 faster Level 2 chargers per square mile.

"Manhattan currently has about 500 chargers for public use, which include Tesla chargers," Bauer said. "We found that we would need to at least triple that capacity."

The study also estimated that a fleet of SAEV taxis drawing power from the current New York City power grid would reduce greenhouse gas emissions by 73 percent and by 58 percent compared to a fleet of automated conventional gas-powered vehicles.

Greenblatt points out that there are still many barriers to the wider penetration of personal EV ownership, including high cost and limited range. "By switching to a shared fleet that's automated, you can provide electric service to people essentially now," he said.

He notes that shared vehicles are best suited for dense, urban environments: "We're not saying these shared vehicles will be the right thing for road trips, but for the vast majority of urban trips, people drive short distances," Greenblatt said.

The researchers said they were motivated to study this topic because they think it will be "the next big thing" in transportation, Greenblatt said.

"For a long time, personal transportation seemed like the hardest problem to solve," Gerke said. "Now suddenly it seems like there's an obvious path to achieving it, which is the electrification of vehicles coupled with changing the way we get around from private ownership to shared approaches. Shared approaches are starting to work in urban areas."

Gerke previously researched lighting efficiency, and was surprised by how quickly the market switched from incandescent to LED bulbs. "It was a better product and it was cheaper overall," he said. "When you have those together, people adopt it really fast. I suspect there will be a similar transformation that will occur in the transportation sector in the next decade - it will occur faster than people think."

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Autonomous taxis would deliver significant environmental and economic benefits, new study shows

More information: "Cost, Energy, and Environmental Impact of Automated Electric Taxi Fleets in Manhattan," Environmental Science & Technology (2018). pubs.acs.org/doi/abs/10.1021/acs.est.7b04732
Citation: Fleet of automated electric taxis could deliver environmental and energy benefits (2018, March 28) retrieved 19 July 2019 from https://phys.org/news/2018-03-fleet-automated-electric-taxis-environmental.html
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Mar 28, 2018
A taxi is much more convenient than the bus or a train so If the price really does come down by an order of magnitude, you can expect traffic and greenhouse gases to go UP substantially.

Mar 28, 2018
It would be hard to program a autonomous vehicle to be aggressive enough to drive in Manhattan. Pedestrians would soon learn that these cars have to stop and would walk in front of them at will. Also it is accepted that drivers cut each other off. The only rule is keep your vehicle as close to the next as you can but don't hit anything. This rule governs the flow of traffic in a very congested area with lots of lane obstructions.

Mar 28, 2018
How have the electric taxis worked out in London so far?

The promise is huge: the most overlooked part of the EV is the LACK OF MAINTENANCE!!

Once a person owns one with current mileage abilities, they will not go back to the ICE.

Mar 28, 2018
We have a 2015 VW e-Golf and a 2013 Tesla Model S, and have not had any maintenance yet at all, except for tire rotation. No oil changes or filters or leaks. No transmission. The brakes last forever since much of it is done by charging the battery in Regeneration.

How much is your personal time worth? Want to go take the emissions test? A tune-up? Valve job? New belts and timing chains? Another oil change? Trips to the gas station?

Electric vehicles will have a huge effect on our society, and we have to be ready to find jobs for those displaced.

Mar 28, 2018
gkam: I'm guessing you don't miss having to periodically stop at a gas station either. To me, that will be the big change. Charging stations can be anywhere there's electricity (subject to having enough capacity available.) I see trickle charging opportunities becoming quite common, for example in parking garages for all day parking or at workplaces.

Mar 28, 2018
Carbon, Tesla just put in a supercharger less then two miles away from the house. My old Model S is grandfathered into the system and gets free charging for as long as the car is working.

I still use my home charger since the power is compensated for by the solar panels.

I am an old EV fan, having been on EPRI working groups in the 1980's which pumped money into the development of them.

Mar 28, 2018
I wonder if we will do anything for all the people who will loose their jobs when taxi's are all autonomous, not to mention all of the semi's, buses, etc.. seems like that would be millions (3.5m truck drivers in usa alone) of jobs no? Driving seems to be a specific skill set that would not easily transfer to another industry.

Seems like it'd be a lot of people near the low end of the economic scale who are going to be told to go back to school on their own dime, unless we figure something out before it becomes an issue.

Mar 28, 2018
Worry more about the hundred million of us who directly and indirectly are enslaved to the ICE.

Take just parts alone. How many moving parts in your Beemer? Just one in an electric motor. And it needs no oil or oil changes or tune-ups or emissions systems, or even a transmission.

Who makes all those parts, and who sells the paper for the air and oil filters, and who sells them groceries, and what about the mechanics and their families and muffler guys and , . . ?

Gas stations and the trucks which supply them and those who maintain the trucks, all will go in one generation or less.

It will be the biggest change in our society since the car, but will happen faster. And the car required more people to support it than the horses, so it also grew the economy. EV's will shrink it.

I have been writing about this for about a year, and ill have to go to see my Congressman.

Mar 28, 2018
I wonder if we will do anything for all the people who will loose their jobs when taxi's are all autonomous, not to mention all of the semi's, buses, etc..

On the other hand we should always ask ourselves: Shouldn't it be the ultimate goal to eliminate jobs that people don't really *want* to do (but rather just have to do because they can't do much else and we're still to stupid to give people what they need automatically)

I mean: by the same argument you made we should not have washing machines (or cars for that matter...think of all the unemployed stable hands!)

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