Since their inception in the early 1800s, electric vehicles (EVs) have been touted as the way of the future. Their ability to eliminate greenhouse gas emissions while offering reliant transportation makes them a promising and green alternative to gas-powered vehicles. When it comes to an EV transformation, what needs to come first – infrastructure development or widespread EV use?
Noah Horesh, Energy Institute research scientist and CSU mechanical engineering alum (B.S. ‘19, PhD ‘23), recently published a paper in Nature Communications delving into EV charging infrastructure deployment across the United States. The study uncovers variations in costs and greenhouse gas emissions for different vehicle categories, charging systems, and locations.
Engineering Source spoke with Horesh to answer some questions about the future of EVs in the US. Answers have been summarized and shortened for clarity.
What different EV charging methods are there?
The most popular is overnight home charging. This method uses a lower power rate to slowly charge the vehicle, taking advantage of the longer dwell time while people sleep.
There’s DC (direct current) fast charging, like the charging stations you typically find in parking lots. It is similar to how people refuel with gas, where you refuel between destinations.
In my recent paper, we’re exploring going beyond DC fast charging and looking at battery swapping, which is popular in China. That’s where you swap out the battery, like going through a car wash – you drive in, it swaps out the battery, and then you exit. It takes about 3 minutes, so much faster than DC fast charging.
The final technology is dynamic wireless power transfer, another kind of in-route charging where you don’t have to stop. Think of it like an HOV lane. You drive in a certain lane to charge on the roadway. This would typically be on high traffic density roadways like interstates where a lot of vehicles, including semi-trucks, can utilize the charging system. This method reduces battery size requirements and can eliminate the need to stop for recharging.
Why are we still unsure about what an EV transition is going to look like?
We are still in the early stages of market development and there’s not enough charging infrastructure in place. As we get higher EV adoption, there’s queuing, which is when there’s a lot of vehicles that need to use a limited number of charging stations. DC fast charging takes around 30 minutes, so cars can have a long wait if there is a line. That’s one of the things that recently came out when Tesla expanded access to their charging network to other brands. Now a lot more people are using those chargers and may have to wait in line. I think these waiting times create an opportunity for faster charging technologies to enter the market, like battery swapping and dynamic wireless power transfer.
What are factors that prevent people from having an EV?
A major factor is the ability to charge their vehicle overnight at their residence. In a previous paper, we looked at deployment cases for providing charging access at multi-unit dwellings like apartment complexes. If you live in a home and you have a garage, even if it’s just a 120-volt outlet, it’s very easy to charge an electric vehicle. But in multi-unit dwellings, most of them will not have a place for you to charge your vehicle.
That’s something new complexes are trying to improve by installing the electrical wiring needed for chargers. But ultimately, they need the consumer to ask for it and use it.
There’s also a lot of uncertainty in terms of costs and how they’re going to change in the future. Right now, there’s a very low electric vehicle adoption level. In this paper, one thing we address is that electric vehicles can either be less expensive or they can be more expensive. It depends on how many people are using the technology, with lower costs achieved with greater EV adoption.
What are some geographic considerations regarding EVs?
Technology economics are different for each location, so there are variations in what technology is cheapest for a given state or urban versus rural areas.
One thing we learned from the study, as we were performing simulations, is that in rural areas different technologies work better, and it matters what technology is deployed. For example, in a rural area, you’re not going to have many people using the technology or using public charging stations. So, to keep infrastructure costs low, a town might install one public DC fast charging station at a relatively cheap cost compared to electrifying an entire mile of roadway or building an expensive battery swapping station that only a few cars use.
In urban areas, you have a lot more vehicles that will use the technology, which can help pay off those infrastructure costs. For example, when capital costs for battery swapping are overcome through high utilization, you can achieve low charging costs by optimizing electricity usage. Since battery swapping allows batteries to be charged any time before the vehicle arrives, the batteries can be charged based on time-of-use electricity prices. With dynamic wireless power transfer, many vehicles can use and pay for the charging system on high traffic density roads. So, it can be pretty cheap per user.
So, what’s next? What is the solution here in terms of charging and infrastructure?
An EV is definitely going to be my next purchase.
If you increase electric vehicle adoption, we should see a higher usage of chargers. Which would then decrease the costs for individuals charging and enable entities to put in more infrastructure. With high levels of electric vehicle adoption, that’s also when we really see meaningful emissions reductions nationwide. If there is limited electric vehicle adoption, the greenhouse gas emissions from transportation today could be about the same in 2050 because of a projected increase in vehicle usage. In other words, nationwide emissions reduction efforts in the transportation sector face a challenge because, although emissions per mile traveled are decreasing, the total vehicle miles traveled are increasing.
Right now, there’s very low electric vehicle adoption. So, when we’re trying to pay for these expensive chargers, we need a lot of people to pay for something. You can distribute the capital cost, making it a lot cheaper for each individual to charge their vehicle.
Having greater electric vehicle adoption works to everyone’s benefit. It’s going to lower transportation costs and reduce emissions to a level that can reach our climate targets.
ASPIRE
Horesh’s recent publication is part of ASPIRE (Advancing Sustainability through Powered Infrastructure for Roadway Electrification), a National Science Foundation Engineering Research Center led by Utah State and partners University of Colorado Boulder, Purdue University, and University of Texas at El Paso.
