Highway EV charging will need a ton of power — sooner than you think

A new report warns that EV charging along Northeast highways will require sports-stadium levels of grid power by 2030. Where are the plans to supply it?

Two bright green Applegreen electric EV chargers at a truck stop
EV charging stations like this one in New York state will soon grow large enough to equal the power grid demand of sports stadiums, according to a new report. (Applegreen Electric)
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The typical electric-vehicle charging site today has a few EV chargers that can make do with the power grid that’s already there. But within the decade, demand for charging battery-powered cars and trucks at sites along highways will start to exceed the power draw of sports stadiums — and supplying that kind of power will require major interconnections to utility transmission grids. 

That’s the warning from a new report that finds there will be truly massive future power needs for EV charging in New York and Massachusetts, two states that have committed to selling only zero-emissions passenger cars by 2035 and moving to emissions-free trucks by 2045 and 2050, respectively. Similar megawatt-scale needs are likely to arise for the EV fast-charging networks already being developed in EV-forward states such as California, and now being planned in all 50 states with billions of dollars of federal funding.

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Right now, when people are talking about capacity” for EV charging, they’re asking which distribution transformer has capacity, or which feeder, or even a substation,” said Dave Mullaney, report co-author and a principal on the Carbon-Free Transportation team of nonprofit RMI.“But when you start to throw tens of megawatts on a distribution system, you’re quickly overloading it.” (Canary Media is an independent affiliate of RMI.) 

By 2030, over a quarter of the 71 highway sites studied in the report will require more than 5 megawatts in charging capacity to meet peak charging demand, the report found — roughly equivalent to the power demand of an outdoor professional sports stadium. By 2045, some sites could reach around 40 MW in peak charging demand, equivalent to a major industrial site. 

The new report — from RMI, clean transportation nonprofit Calstart, Northeast U.S. utility National Grid, and fleet-vehicle technology-services companies Geotab and Stable Auto — is one of the first of its kind to examine future charging needs with grid power availability in mind. Today, charging developers choose where to site stations based on factors including traffic, expected utilization and land availability, the report notes. But electric infrastructure should play an equally critical role and can drastically impact development costs and timelines.” 

It takes only a few months to install EV chargers, but it takes years to approve and build major transmission grid extensions. Only a handful of truly megawatt-scale charging hubs now exist, and some of them are already facing delays in getting the grid connections they need, whether in densely packed urban areas or at remote highway sites.

If state agencies and utilities don’t coordinate on how to supply high-voltage grid interconnections to the mega-charging hubs coming down the pike, the result could be delays and higher costs that hinder expansion of a technology that’s key to decarbonizing transportation. 

If we wait 10 years or 15 years to make these investments, I can guarantee you they’ll be double or triple” what they would be if they were planned well in advance, said Brian Wilkie, National Grid’s director of transportation electrification in New York. On the other hand, proactive planning and anticipatory investment” could lower the cost of project implementation by about one-third compared to projects that fail to take grid capacity and availability into account, he estimated. 

That’s why National Grid is sharing this report with transportation agencies, utility regulators, community stakeholders and EV-charging companies, he said. What we believe needs to happen is the transportation planning sector and the utility sector need to come together and join forces.” 

From bare-bones highway charging to a multi-megawatt future

This challenge has not yet been taken up by most of the states implementing the National Electric Vehicle Infrastructure (NEVI) Formula Program, said Benjamin Mandel, Calstart’s senior director for the Northeast region. Created by last year’s federal infrastructure law, the program has $5 billion to help every state build at least a skeleton of charging networks along major transportation routes, while allowing states that currently have relatively low rates of EV adoption to avoid installing more costly chargers than they’re expected to need in the next few years. 

But while initial installations made with NEVI funds might not draw a lot of power, state governments and their private partners would be wise to locate those small charging hubs where they’ll have the capacity to grow. 

NEVI calls for at least four high-speed charging stations supplying at least 150 kilowatts of charging along every 50 miles of major highway corridors — a peak load of a little more than half a megawatt per site. But the new report presumes that high-traffic sites will need 10 to 20 chargers capable of supplying 350 kilowatts apiece within the next five years — which would pull up to 7 megawatts of peak load — and 30 to 40 chargers in the next 10 years, or as much as 14 MW of peak load. 

The following graphic shows how sites with the amount of charging needed to support New York’s and Massachusetts’ EV targets will drive increasingly high peak loads at a typical mixed-use highway plaza serving both passenger EVs and medium- and heavy-duty electric vehicles in New York or Massachusetts by 2035

The capacity required for useful highway charging sites is certainly greater than the current distribution system can provide in many instances,” Mandel said. In other words, the low-voltage network that homes and businesses normally connect to won’t be able to handle loads this large; high-voltage transmission grids will have to be tapped to provide this level of power. 

NEVI is designed primarily to give drivers of passenger EVs confidence that they’ll be able to charge during longer trips. But adding electric trucks to the equation boosts charging power demand dramatically, particularly in states such as New York and Massachusetts that are adopting advanced clean trucks regulations like those first promulgated by California. 

The report projects that medium- and heavy-duty EVs would be responsible for three-quarters of average daily energy demand at the charging sites it studied by 2045, and will drive significantly higher demand at typical truck stops as early as 2035, as this graphic indicates. 

So far, however, only a handful of states have integrated future demands from medium- and heavy-duty vehicle electrification as part of their NEVI plans, Mandel said. That makes sense, given the early scope of the federal program. But in future years, our analysis shows that early planning, along with this coordination, represents a unique opportunity to develop infrastructure in a way that is cost-effective and allows states to meet their policy targets in a timely manner,” he said. 

Making the connections between highways and transmission lines 

Fortunately, there happens to be a significant overlap between highways and high-voltage transmission networks across most of the U.S., Wilkie pointed out. That’s certainly the case in New York and Massachusetts, where the report narrowed down hundreds of potential high-volume charging sites to 71 well-situated locations that combine preexisting highway rest stops or truck stops with proximity to parts of the National Grid transmission network suitable for being tapped for megawatt-scale power, as shown on this map.

This kind of data is valuable for the companies building high-volume public charging networks across the country. Charging-network developers Electrify America and EVgo are partnering with rest-stop operators Love’s Travel Stops and Pilot and Flying J, respectively. Startups including WattEV and Zeem Solutions are building charging hubs for trucks and commercial vehicles near freight hubs. Terawatt Infrastructure, a startup that’s raised $1 billion to develop charging sites across the country, is targeting highway charging sites along with fleet depots to serve the corporate EV fleets it’s working with.

There’s kind of a line in the sand being drawn between electric-vehicle charging and the grid itself,” said Ethan Goldsmith, an investment partner at Keyframe Capital, an investor in Terawatt Infrastructure. It seems like all of the effort to date has been on the charger side of that line, and very little, if any, discussion or funding is going onto the other side of that line.” 

That’s a problem in his view, given that the majority of the capital required to bring EV charging to scale will be going to transmission and distribution and interconnection, not the chargers themselves,” he said. Right now, it’s far from clear how different utilities and state regulators will coordinate the grid interconnections and expansions needed to serve growing demand from EV-charging developers, and which party will be tasked with paying for it, he added.

A growing number of EV-charging sites are adding batteries that can store up grid power at times when chargers are sitting idle and provide it when charging loads exceed available grid capacity, he noted. But that’s far from the most optimized solution,” he said, particularly as loads grow to multi-megawatt scale. 

RMI’s Mullaney highlighted the need for structures that can align how utilities plan ahead for grid extensions and improvements with how state transportation agencies and private-sector EV-charging developers plan for where to install chargers. This can’t be a battle of attrition, one-by-one rate cases or site selections,” he said. We have to move at scale. The administrative and regulatory processes have to be aligned with that.” 

Coordinating this work across utility jurisdictional and state boundaries adds complexity, Mandel pointed out, which means that regional and possibly federal coordination is critical.” Utilities have banded together to coordinate EV charging on interstate highways, and several studies of specific routes, such as the I-5 running from San Diego to British Columbia, have taken a crack at determining the optimal spots for heavy-duty EV charging. Calstart and National Grid have submitted proposals to the U.S. Department of Energy for a planning partnership to develop an East Coast commercial EV corridor. 

Wilkie emphasized that the report’s analysis of New York and Massachusetts showed that National Grid’s existing infrastructure can absolutely accommodate” the power needed for EV charging as it grows across the region. The question is the timing and the magnitude,” he said. One site could be very affordable, while another site could be incredibly expensive.” 

National Grid has shared its grid analysis with transportation agencies in both states. It’s also working on concepts for aligning grid investments with charging-station deployments, Wilkie added. In the U.K., where National Grid is headquartered and operates the national transmission grid, EV-charging developers can pay back the cost of grid infrastructure built to serve them through paying a few cents per kilowatt-hour of charging they provide, rather than being forced to finance the cost of building that infrastructure all at once, he noted by way of example. 

The time for pilots is over,” he said. It’s important now to start trying some things. We need to start getting some steel in the ground.”

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Jeff St. John is director of news and special projects at Canary Media.