Highway charging stations for EVs may need as much electricity as a small town
Energize Weekly, November 30, 2022
A growing number of electric cars and trucks on highways will by 2035 require charging stations demanding the same power as an outdoor sports arena or even a small town, according to a study by grid and electric-charging companies.
The study modeled the demands and impacts of electric vehicle (EV) use on highways in Massachusetts and New York – two states that have committed to increase use of electrical cars and trucks.
“Electric vehicle adoption has reached a tipping point,” the study said. “It is now accelerating toward mass market adoption, particularly in states taking proactive measures to encourage transportation electrification.”
The study was done by National Grid, a provider of gas and electricity in New York and Massachusetts; CALSTART, which develops clean transportation technology; Stable Auto, which optimizes charging infrastructure; and clean energy consultant RMI.
New York and Massachusetts have adopted laws requiring all sales of new passenger cars and light-duty trucks be zero-emission by 2035.
Both states have adopted the Advanced Clean Trucks regulation, which mandates an increasing number of zero-emission medium- and heavy-duty vehicle (MHDV) sales starting in 2025. New York state also has a goal of 30 percent zero-emission MHDV sales by 2030 and 100 percent by 2045.
The analysis found that not only will the growth in electric cars and trucks require more charging stations, but it also will pose a challenge to the existing grid.
“Currently, the electric grid does not have sufficient delivery headroom for highway charging at the scale identified by this study and required by policy targets,” the study said.
A typical highway site will need 20 or more fast-chargers to meet drivers’ needs, leading to a drastic increase in power demand compared to usage today.
The major driver for the increased electricity demands will be the growth in MHDV, which by 2045 will consume 75 percent of the daily average energy needs across the study area.
By 2030, more than a quarter of the 71 highway sites studied – these included service plazas, truck stops and off-highway locations – will require more than 5 megawatts (MW) of charging capacity to meet peak charging demand – equal to the electric demand of an outdoor professional sports stadium.
A large service plaza for both autos and trucks in 2035 could require as much as 19 MW of capacity, similar to the electricity demand of a small town, the modeling found.
Some high-demand charging sites could require about 40 MW in peak charging capacity by 2045, which is equivalent to the electric load of a major industrial site.
“This level of electric demand at a specific site may exceed the delivery limits of a typical distribution system interconnection and therefore require interconnection to the high-voltage transmission system,” the study said.
Interconnection upgrades can be costly and take four to eight years to complete, but an overlap between highway rights-of-way and rights-of-way for high-voltage transmission lines will help in creating the needed interconnections.
“It may not be feasible to extend the transmission network to every site, particularly in locations where there would be impacts to local residents and the environment, but there are opportunities for minimal extensions or taps of transmission lines to many highway charging locations,” the study said.
The need to upgrade the grid to meet the demands of electric cars could come as early as 2025, but the study argues against making incremental upgrades, since those investments could be stranded as future electricity demands required larger capacity.
“If we prioritize short-term needs over the long-term need, we risk a situation where site operators – and drivers – have to wait years for upgrades to grid infrastructure before new chargers can be installed, which could frustrate drivers and negatively impact confidence in EV charging,” the study said.
