Ask a Scientist: How to Get a Charge out of Your EV

December 8, 2021
Electric vehicles at EVgo charging stationsEVgo Network/flickr
Elliott Negin
Senior Writer

The Biden administration’s vision of an electric vehicle (EV) charging station network across the country came closer to becoming a reality last month when President Biden signed the $1.2-trillion Infrastructure Investment and Jobs Act into law. The bill included $7.5 billion for EV charging infrastructure, which could get us close to reaching the president’s goal of a half a million chargers. Over time, more chargers should help alleviate potential EV buyers’ worries about where they can get their next electron fill up.

Even without that network yet in place, US EV sales this year were on track to set a record, boosting the number of EVs on the road to an estimated 400,000, and industry forecasters predict sales will double over the next two years.

Despite this rapid growth, EV sales likely will amount to less than 4 percent of overall US vehicle sales this year, so there is a long way to go to fulfill President Biden’s executive order calling for zero-emissions vehicles to comprise half of all new passenger vehicles sold by 2030, let alone UCS’s goal of 100 percent EV sales by 2035.

We recently received a query from a UCS member from Toledo, Ohio, who is thinking about buying an EV. “I currently own a hybrid (Prius),” Debbie P. wrote, “and would consider getting an EV for my next vehicle, but am concerned about sufficient access to charging places when traveling and also about how long it takes to charge such a vehicle.”

I turned to Samantha Houston, a UCS senior vehicles analyst, to address Debbie P.’s question. Among other things, Ms. Houston pays close attention to EV infrastructure issues, and earlier this year, she posted a fact sheet titled Federal Support for EV Charging: Policies for Rapid, Equitable Investments. Before joining the UCS staff in 2018, she was an independent consultant working on vehicle emissions standards, climate policy modeling, and other issues for a range of clients, including Climate Interactive, a nonprofit think tank. She holds a master’s degree in technology and policy from the Massachusetts Institute of Technology.

Below is an abridged version of our conversation.

EN: Right after the good news about the infrastructure bill, we got Debbie P.’s very relevant question about charging EVs. Where are we now with charging infrastructure and how fast can the country ramp up to meet the Biden administration’s goal?

SH: Before we get to long-distance travel, let’s talk about routine, day-to-day driving. Most people drive less than 50 miles per day, so charging a car that is going to be parked anyway is more than sufficient to fill up for day-to-day driving. For many people, that kind of opportunistic charging can be done very conveniently with relatively low-cost, low-powered chargers at home. Workplaces can provide another great opportunity to charge EVs for a number of hours at a time.

Of course, people who can’t install a charger at home or at work because their workplaces don’t provide charging can rely on public chargers in their community—if they’re available. I have a couple of friends dealing with this situation. One relies primarily on charging at his local grocery store while he does his weekly shopping. The other charges at a Tesla Supercharger for half an hour every few weeks.

That said, we obviously need more chargers, particularly for multi-unit housing and rental units. That’s why federal, state and local funding, including what Congress provided in the bipartisan infrastructure bill for public charging, is so critical. With that kind of money in hand, the question of how fast we can ramp up will really come down to how quickly state and federal programs can dedicate funds for charging sites and how much municipalities, utilities and installers can streamline the engineering, design, permitting, inspections, and grid connection process.

EN: Debbie P. asked about how long it would take to charge an EV. It gets a bit complicated, because there are at least three kinds of chargers, right?

SH: Right. The most basic way to charge an EV would be to plug its power cord into a regular outlet. That’s called Level 1. Level 2 chargers provide more power, using the same kind of plug used for a clothes dryer. Level 3, or DC fast charging, has two-and-half to 20 times more power than Level 2, depending on the kilowatt (kW) rating, and would add miles to the vehicle’s driving range much faster, although that speed often comes at a cost.

How long it takes to charge at any of those levels depends on how big the battery is, how much “fuel” in kilowatt hours (kWh) you need, and the power rating of the charger.

Let’s say you’re looking at an EV of pretty average efficiency that takes 34 kWh to drive 100 miles. For day-to-day driving, imagine you typically drive 25 miles per day and you want to start each day with your EV’s battery at 100 percent. You could charge the battery in 4.5 hours with a Level 1 charger or a little more than an hour with a residential Level 2 charger.

For occasional road trips, imagine you want to add 150 miles of range when your EV battery is getting low. If you only have access to a commercial Level 2 charger, it could take anywhere from 3 to 7 hours to charge depending on the charger’s power output. But with a 50 kW Level 3 fast charger it would take about an hour. And if you had access to a 150 kW it would take only about 20 minutes.

EN: So it sounds like charging for daily driving isn’t a big challenge. But what if Debbie P. wants to take a road trip?

SH: Charging along travel corridors has come a long way, and I’m not just talking about the Tesla charging network. Electrify America, for example, has opened an average of four stations every week since 2018, mainly along interstate highways. In fact, we already have roughly 20 percent of the Biden administration’s goal of a 500,000-charger network in place, with more than 100,000 public EV chargers as of the first quarter of this year, according to the Energy Department.

So charging stations may be already in place to accommodate the long trips Debbie plans to take. For people like Debbie who are on the market for a new (or new-to-them) car, I recommend mapping out longer trips they think they might take, say from Toledo to Washington, D.C., to confirm charging availability, given the EV’s particular battery range. Some automakers have tools to automatically calculate such a route. You can also use a resource such as PlugShare.com to identify charging locations, power level, port type, and cost.

EN: Besides charging issues, according to a recent public opinion survey, price and range are obstacles for potential EV buyers. Younger shoppers—Gen Z and Millennials—are not as concerned about range, but they have less disposable income than older folks. What should the federal and state governments do to make it easier for people to choose an EV next time they buy a car?

SH: Certainly, charging deployment alone, as critical as it is, cannot guarantee US drivers will adopt EVs as rapidly as necessary to reach our carbon reduction goals. We also have to address the very real obstacles to buying the vehicles. EV incentives, such as the federal tax credit, can help bridge the gap on upfront cost as long as EVs are more expensive than their equivalent gasoline counterparts.

But incentive programs can’t only focus on helping people who can afford to buy a new car. As it turns out, most people buy used cars. Used-car purchases outnumber new car purchases by more than two to one, and the gap is even more pronounced for people of color and low-income families. Some states now have incentives in place for used EVs and UCS is advocating for a federal used EV credit as well. These incentives would provide more choices for potential car buyers no matter what their economic status is. Incentive programs also must be designed so that all car buyers can access them and they don’t drive up the price of EVs on the new or used market. And keep in mind, EV sticker prices are bound to fall as batteries improve and more EVs are manufactured and sold. It is all about economies of scale.

As the survey you mentioned points out, range anxiety is becoming less of an issue, given the current generation of EVs are meeting or exceeding the range of their gasoline counterparts. And when more charging stations are installed in cities and along highways, range anxiety will dissipate even more.

The main point is that federal, state and local policies have to address all aspects of the EV driving system to make EVs accessible for anyone who needs a personal vehicle. EVs are the future—hopefully the near future—and no one should be left behind.