Using data from 10 million New York City taxi rides, researchers at the Department of Energy’s Lawrence Berkeley National Laboratory constructed computer models to analyze the cost, efficiency, and emissions impact of autonomous electric taxis. Their study, entitled “Cost, Energy, and Environmental Impact of Automated Electric Taxi Fleets in Manhattan,” (paywall protected) came up with several unexpected conclusions.
Smaller Batteries Are Best
“The EV industry is focusing on the personal car market, trying to make the range as large as possible,” says Jeffrey Greenblatt of Berkeley Lab. “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 study found that with the proper EV charging infrastructure in place, a battery range of 50 to 90 miles would be best for congested urban areas. That would require 66 Level 2 chargers per square mile or 44 fast chargers per square mile. “Manhattan currently has about 500 chargers for public use, which include Tesla chargers,” says lead author Gordon Bauer said. “We found that we would need to at least triple that capacity.” The researchers say the current New York City electrical grid could handle that many chargers in the city without extensive and expensive upgrades.
Lower Emissions, Lower Costs
Assuming a proper charging infrastructure is in place, the computer models suggest autonomous electric taxis would reduce greenhouse gas emissions by 73% and energy consumption by 58% compared to a fleet of automated conventional gas powered taxis. And here’s the best part. “By switching to a shared fleet that’s automated, you can provide electric service to people essentially now,” Greenblatt tells Science Daily. 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.”
Privately owned electric cars are still too expensive for many people, but for those living in urban areas, autonomous electric ride-sharing can make it possible for people to travel in and around the city in an environmentally friendly way that is affordable without ever having range anxiety. The researchers said they were motivated to study this topic because they think it will be the next big thing in transportation.
Brian Gerke, another member of the research team, compares the situation today to the LED market a few years ago. “It was a better product and it was cheaper overall,” he says. “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.”
Lower emissions, less cost, reduced energy consumption, and fewer cars on the road. If you live in a city and could have all that, why wouldn’t you?