The paradox of electric vehicles

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Researchers at The Ohio State University develop a simulation technique to find optimal locations for electric vehicle charging stations.

August 9, 2017

While sales of electric vehicles (EVs) continue to grow each year, they only make up 1% of the current passenger vehicle market. With more consumers interested in purchasing EVs, the vehicle industry finds itself in a difficult situation – consumers are not buying EVs because adequate charging stations aren’t available, and investors are not building stations without enough demand.

Ramteen Sioshansi, associate professor of integrated engineering at The Ohio State University’s College of Engineering, is addressing this Catch 22 using data sets from the Mid-Ohio Regional Planning Commission (MORPC) that model the typical driving patterns around Columbus, Ohio. These simulations locate high traffic areas optimal for EV charging stations and identify the loads that electric distributors can handle.

“We took the data sets of the driving patterns in Central Ohio and randomly selected 3%” as a market share estimate for EVs, Sioshansi says. “We then used this subset to see where the vehicles are driving, when they are driving, and what happens to the state of charge of the battery over the course of the day.”

Sioshansi’s research found the optimal location for charging stations within Columbus to be the I-270 beltway. Being a major roadway with retail, commercial areas, and large employers nearby, this location can serve the greatest number of drivers with the minimal amount of stations.

According to simulation results, universities delivered the highest service levels due to parking times being long but shorter than the full 8-to-9 hours EVs tend to be parked at workplaces. This allows a charger to be used by multiple EVs daily, allowing depleted battery energy to be replaced between uses.

Universities and workplaces could use Level 1 and Level 2 charging technologies. Level 1 chargers use a standard wall outlet and provide 110V/15A, while Level 2 chargers use a larger appliance circuit, providing 220V/15A to 30A. These technologies require prolonged parking, ranging from 6 to 12 hours for a full charge.

The third technology, Level 3 or DC fast chargers, uses a higher voltage ranging from 400V to 500V. A Level 3 charger can fully charge an EV battery in as little as 30 min., making them well-suited for in-and-out scenarios where drivers recharge vehicles and leave in a period similar to gas stations.

“I think that for a lot of consumers the hesitance to commit to electric vehicles is the uncertainty of if you’ll be able to recharge the vehicle reliably and be able to complete your daily trips,” Sioshansi says. “Having a network of charging stations is enough empirical evidence… that charging infrastructure would go a long way.”

Though Sioshansi used Central Ohio as a test market for his research, his findings are not specific or unique to the area. This research can help address the broader issue of where to place EV charging stations to optimize their efficiency and their accessibility to drivers across the country.

The Ohio State University

About the author: Haley Rischar is an editorial intern at TMV. Inquiries about this story can be sent to 216.393.0271 or