Decades of NREL Research Power Electric Vehicle Revolution Progress
Depending upon where you work or live, the most visible sign of the clean energy transition you see may be an electric vehicle (EV). An ever-increasing number of motorists are bypassing the gas pump and plugging in instead.
Electric vehicles have moved beyond novelty to ubiquity. To wit: Approximately 1.6 million light-duty electric vehicles were sold in the United States last year, a significant increase from 600,000 only two years earlier. And those sales figures are expected to keep climbing.
To keep pace with the accelerated adoption of EVs, a national network of private and public charging ports offering convenient, reliable, and affordable charging options will be required to secure long-term buy-in from drivers.
Boosting Confidence in Charging Stations
Charging stations must be widespread and reliable to entice motorists to make the switch to an EV as their primary mode of transportation, according to Eric Wood, a senior EV charging infrastructure researcher at the U.S. Department of Energy’s (DOE's) National Renewable Energy Laboratory (NREL).
“This is the fundamental challenge for the industry right now,” Wood said. “Some people like to talk about alternative-fuel vehicles and their infrastructure as a chicken-and-egg problem. But I really think it’s more appropriate to think about infrastructure—specifically, charging stations—needing to lead the market. You need to have these stations be visible and available for people to feel confident in buying an electric vehicle and committing to make it their daily transportation mode of choice.”
This was a key finding from NREL’s 2030 National Charging Network: Estimating U.S. Light-Duty Demand for Electric Vehicle Charging Infrastructure report, which Wood coauthored. The analysis points to the need for a mix of publicly accessible charging stations along highways and near homes and workplaces, and private charging ports at single-family homes, apartments, and offices. The scenario also calls for fast-charging stations available to the public and slower charging in private homes where speed is not of the essence.
Amid growing concern about climate change, researchers at NREL are developing cutting-edge tools and producing groundbreaking research to study zero-emission vehicles and related infrastructure, including their integration into the energy system. Two of the laboratory’s world-class resources include the EVI-X Modeling Suite of Electric Vehicle Charging Infrastructure Analysis Tools (EVI-X) to help guide deployment of charging infrastructure and the Transportation Energy & Mobility Pathway Options (TEMPO) model to explore pathways for achieving long-term climate goals. Transportation accounts for the United States’ largest share of greenhouse gas emissions with more than 90% of the energy supplied by petroleum.
Wood said a trio of factors are attracting consumers to EVs, including an interest in decreasing greenhouse gas emissions. The performance of EVs also plays a part, as do lower operating costs.
“This is especially true if you can do most of your charging at home and take advantage of retail electricity rates,” he said.
EV sales so far have tended to be highest in states that have enacted regulations and incentives encouraging both the supply and demand of zero-emission vehicles (ZEVs) and supporting infrastructure, said Arthur Yip, an NREL transportation researcher. These policy tools stimulate consumer demand and encourage automakers to ship more EVs to those states and do more marketing there.
California, which has the largest concentration of EVs and charging stations, has mandated that by 2035 all new light-duty vehicles sold in the state must be ZEVs. Other states are following California’s lead. But that does not mean that highways and roadways will be jammed only with EVs.
“Keep in mind, it takes about two decades to turn over the existing vehicle stock,” said NREL’s Matteo Muratori, who leads the laboratory’s Transportation Energy Transitions Analysis group. “The fact that you’re only selling EVs doesn’t mean that on the road you will only see EVs, because we don’t throw away every car every single year. Even with 100% EV sales in 2035, we still expect around 10%–20% of gasoline vehicles on the road in 2050, without accelerated replacement.”
EV adoption varies widely. Nationwide, about 8% of cars sold last year were electric, “but there is a big geographic difference,” Muratori said. “It was over 20% in California, and in some places it is closer to 1%.”
More Reliable Charging, In More Places
Researchers at NREL and other DOE laboratories are collaborating with the Joint Office of Energy and Transportation to improve reliability at charging stations, as motorists who use EVs need confidence in their ability to find a convenient charging station—and have a pleasant experience while doing so. Similarly, more charging stations must open in parallel with a growing number of EVs hitting U.S. roads to keep up with the pace of adoption.
Andrew Meintz is the chief engineer for electric vehicle charging and grid integration at NREL and the overall lead of DOE’s Electric Vehicles at Scale Lab Consortium. Known as EVs@Scale, the effort by NREL and other national laboratories drives infrastructure research and development.
“We’re focused on improving all aspects of EV charging infrastructure to make the choice of buying an EV easy for drivers,” Meintz said. “Our goal is to make charging seamless, so they can fuel it, just like they can with their gas vehicle, go on a road trip, and not be concerned about how far they can travel between charges. I know a few people—not to mention myself—who have taken long road trips in these vehicles. It’s possible. But the charging stations need to be reliable and available. People should be able to expect every time they go to a charging station, they’re going to get the experience they want.”
Beyond cost, the ease of charging an EV also plays a role in the purchase decision. Wood said he has read consumer surveys that revealed people without an EV say they would want to charge their cars quickly, with plenty of public charging locations available.
“Once people get into an electric vehicle, you find their mindset really changes,” he said. “We see that the preference is really for charging that is low cost and convenient. Charging at home is typically the location that offers the best convenience and cost.”
NREL’s Brennan Borlaug, a transportation research analyst, said the early adopters of EVs have primarily lived in single-family homes with garages where they could install a charger. This situation can make charging an EV even more convenient than refueling a conventional vehicle for typical daily travel.
“But if we truly want EVs to reach the mass market, they must appeal to a broader set of drivers, including those renting their homes or living in apartments without a dedicated home charger,” Borlaug, a coauthor of the 2030 National Charging Network study, said. “We need to be deploying charging stations to meet the anticipated demands of today’s and tomorrow’s drivers, not yesterday’s.”
Wood estimates that because they live in apartments or other multifamily properties, a quarter of motorists do not currently have charging readily available.
“There will be some apartment complexes that offer charging on-site, either paid or as a free amenity to their tenants,” he said. “But there are a lot of challenges for property owners to provide that charging, and there’s not always a clear incentive for them to do so.”
That creates a need for EV chargers at workplaces, and not just at office buildings.
“Some of the people most likely to need a charger at work are those who work in retail and industrial settings,” Wood said. “Access to charging at strategic workplaces is a really important piece of the puzzle.”
Three types of charging scenarios exist. The first two are AC chargers, dubbed Level 1 and Level 2, which recharge EV batteries in a matter of hours. Someone with access to a home charger can simply plug in a vehicle overnight and have a full battery by morning. Meanwhile, a network of DC fast-charging charging stations is intended to be set up along highways for travelers to continue their journey.
With millions of EVs already on the road, work remains to fill in the gaps in the charging network. The Bipartisan Infrastructure Law includes billions of dollars earmarked for a backbone of high-speed chargers regularly spaced along major roads and highways.
“The charging network is highly concentrated and also fragmented,” Borlaug said. “We're still at a very early stage in the market. Public chargers were initially deployed in and around areas where EVs were being adopted. This is logical but has produced a network that is not necessarily the most connected or equitable.”
To address the issue of equity and electric vehicles, NREL researchers developed the Electric Vehicle Infrastructure for Equity (EVI-Equity) model. This model is in response to an implicit bias when it comes to where to build charging stations, which have tended to skip low-income and rural areas. The use of EVI-Equity guides more equitable and just EV adoption and infrastructure deployment.
Solving Infrastructure Challenges
The divide between urban and rural areas cannot be overlooked in determining where to install charging stations.
“People living outside of urban areas tend to drive longer distances, and they tend to drive bigger cars that use more energy,” Muratori said. “That makes it a bit more challenging to electrify. On the other hand, the cost savings are more significant and you’re more likely to have a place to charge at home, which balances things out to an extent.”
He said urban drivers have been faster at embracing EVs in part because the initial vehicles available tended to be smaller cars and used for shorter distances. Now that more manufacturers have introduced electric pickup trucks and SUVs, interest in EVs has accelerated in rural areas.
Yip and fellow researchers analyzed millions of data points to determine how much EVs have been driven. Relying on odometers from used cars for sale, they found battery-powered vehicles on average have been driven less than gasoline-fueled vehicles. However, among EVs, researchers found that Tesla models racked up the most mileage, almost comparable to conventional cars. Tesla vehicles, compared to the other EVs represented in the data, have historically benefited from longer ranges and exclusive charging network access. Today’s EV market now offers similar levels of range performance and charging access.
Another area that needs to speed up is the time it takes to open a new charging station.
“The timeline that it takes to request service from the local electric utility to when you actually get your site energized can vary dramatically across the country right now,” Wood said. “In some cases, it may take over a year between when you request service from a utility and when you actually get power. Speeding up this process is key to helping the industry be nimbler and more efficient.”
That extends to delays in the local permitting process, which he said could also take a year. “Part of that is the novelty of electric vehicle charging. There are not always local permitting officials that are familiar with the technology, not always familiar with what an electric charging station looks like and what the requirements might be.”
NREL researchers are trying to change that. Ranjit Desai, a transportation researcher at the laboratory, is the primary architect of an online tool designed to accelerate the deployment of charging stations. The new tool, called Electric Vehicle Infrastructure – Locally Optimized Charging Assessment Tool and Estimator (EVI-LOCATE), originally was developed for federal agencies but will be made available to the public later this year.
“EVI-LOCATE is unique in that it estimates the cost of installing charging stations at any given location,” he said. The cost varies depending on several factors such as how far away the location is from a transformer and where the charging station is installed.
Desai has also been working since last fall on a project to determine the “soft costs” of installing a charging station. That is everything beyond the hardware, installation costs, and equipment and includes the costs as well as the time spent waiting for permits and coordinating with utilities. Recommendations will follow on ways to trim the soft costs.
The reasons for driving an EV are many. Whether the desire is to curb emissions or reduce reliance on fossil fuels, motorists are moving past gas stations in increasing numbers. True, there are still some obstacles to overcome, but thanks to assistance from researchers at NREL, these challenges are merely bumps along the way and not roadblocks.
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